Merge remote-tracking branch 'origin/upstream-master' am: d47448d647 am: 9cded8880a

Original change: https://android-review.googlesource.com/c/platform/external/liburing/+/1773366

Change-Id: I0bb365add26100f6240f4ae5be163510f82ac3a2
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..7a6f75c
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,130 @@
+*.rej
+*.orig
+*~
+/*.patch
+
+*.o
+*.o[ls]
+
+/src/liburing.a
+/src/liburing.so*
+/src/include/liburing/compat.h
+
+/examples/io_uring-cp
+/examples/io_uring-test
+/examples/link-cp
+/examples/ucontext-cp
+
+/test/232c93d07b74-test
+/test/35fa71a030ca-test
+/test/500f9fbadef8-test
+/test/7ad0e4b2f83c-test
+/test/8a9973408177-test
+/test/917257daa0fe-test
+/test/a0908ae19763-test
+/test/a4c0b3decb33-test
+/test/accept
+/test/accept-link
+/test/accept-reuse
+/test/accept-test
+/test/across-fork
+/test/b19062a56726-test
+/test/b5837bd5311d-test
+/test/ce593a6c480a-test
+/test/close-opath
+/test/config.local
+/test/connect
+/test/cq-full
+/test/cq-overflow
+/test/cq-overflow-peek
+/test/cq-peek-batch
+/test/cq-ready
+/test/cq-size
+/test/d4ae271dfaae-test
+/test/d77a67ed5f27-test
+/test/defer
+/test/double-poll-crash
+/test/eeed8b54e0df-test
+/test/eventfd
+/test/eventfd-disable
+/test/eventfd-ring
+/test/fadvise
+/test/fallocate
+/test/fc2a85cb02ef-test
+/test/file-register
+/test/file-update
+/test/files-exit-hang-poll
+/test/files-exit-hang-timeout
+/test/fixed-link
+/test/fsync
+/test/hardlink
+/test/io-cancel
+/test/io_uring_enter
+/test/io_uring_register
+/test/io_uring_setup
+/test/iopoll
+/test/lfs-openat
+/test/lfs-openat-write
+/test/link
+/test/link-timeout
+/test/link_drain
+/test/madvise
+/test/mkdir
+/test/nop
+/test/nop-all-sizes
+/test/open-close
+/test/openat2
+/test/personality
+/test/pipe-eof
+/test/pipe-reuse
+/test/poll
+/test/poll-cancel
+/test/poll-cancel-ton
+/test/poll-link
+/test/poll-many
+/test/poll-ring
+/test/poll-v-poll
+/test/probe
+/test/read-write
+/test/register-restrictions
+/test/rename
+/test/ring-leak
+/test/ring-leak2
+/test/self
+/test/send_recv
+/test/send_recvmsg
+/test/sendmsg_fs_cve
+/test/shared-wq
+/test/short-read
+/test/shutdown
+/test/sigfd-deadlock
+/test/socket-rw
+/test/socket-rw-eagain
+/test/splice
+/test/sq-full
+/test/sq-full-cpp
+/test/sq-poll-dup
+/test/sq-poll-kthread
+/test/sq-poll-share
+/test/sqpoll-disable-exit
+/test/sqpoll-exit-hang
+/test/sqpoll-sleep
+/test/sq-space_left
+/test/statx
+/test/stdout
+/test/submit-reuse
+/test/symlink
+/test/teardowns
+/test/thread-exit
+/test/timeout
+/test/timeout-new
+/test/timeout-overflow
+/test/unlink
+/test/wakeup-hang
+/test/*.dmesg
+
+config-host.h
+config-host.mak
+config.log
+
+liburing.pc
diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..e02fdd0
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,22 @@
+language: cpp
+os:
+  - linux
+compiler:
+  - clang
+  - gcc
+env:
+  matrix:
+    - BUILD_ARCH="x86"
+    - BUILD_ARCH="x86_64"
+  global:
+    - MAKEFLAGS="-j 2"
+matrix:
+  exclude:
+    - os: linux
+      compiler: clang
+      env: BUILD_ARCH="x86" # Only do the gcc x86 build to reduce clutter
+before_install:
+  - EXTRA_CFLAGS="-Werror"
+script:
+  - ./configure && make
+  - sudo make runtests || true
diff --git a/COPYING b/COPYING
new file mode 100644
index 0000000..e5ab03e
--- /dev/null
+++ b/COPYING
@@ -0,0 +1,502 @@
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+
+    <one line to give the library's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Lesser General Public
+    License as published by the Free Software Foundation; either
+    version 2.1 of the License, or (at your option) any later version.
+
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public
+    License along with this library; if not, write to the Free Software
+    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+
+Also add information on how to contact you by electronic and paper mail.
+
+You should also get your employer (if you work as a programmer) or your
+school, if any, to sign a "copyright disclaimer" for the library, if
+necessary.  Here is a sample; alter the names:
+
+  Yoyodyne, Inc., hereby disclaims all copyright interest in the
+  library `Frob' (a library for tweaking knobs) written by James Random Hacker.
+
+  <signature of Ty Coon>, 1 April 1990
+  Ty Coon, President of Vice
+
+That's all there is to it!
diff --git a/COPYING.GPL b/COPYING.GPL
new file mode 100644
index 0000000..d159169
--- /dev/null
+++ b/COPYING.GPL
@@ -0,0 +1,339 @@
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 2, June 1991
+
+ Copyright (C) 1989, 1991 Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+                            Preamble
+
+  The licenses for most software are designed to take away your
+freedom to share and change it.  By contrast, the GNU General Public
+License is intended to guarantee your freedom to share and change free
+software--to make sure the software is free for all its users.  This
+General Public License applies to most of the Free Software
+Foundation's software and to any other program whose authors commit to
+using it.  (Some other Free Software Foundation software is covered by
+the GNU Lesser General Public License instead.)  You can apply it to
+your programs, too.
+
+  When we speak of free software, we are referring to freedom, not
+price.  Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+this service if you wish), that you receive source code or can get it
+if you want it, that you can change the software or use pieces of it
+in new free programs; and that you know you can do these things.
+
+  To protect your rights, we need to make restrictions that forbid
+anyone to deny you these rights or to ask you to surrender the rights.
+These restrictions translate to certain responsibilities for you if you
+distribute copies of the software, or if you modify it.
+
+  For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must give the recipients all the rights that
+you have.  You must make sure that they, too, receive or can get the
+source code.  And you must show them these terms so they know their
+rights.
+
+  We protect your rights with two steps: (1) copyright the software, and
+(2) offer you this license which gives you legal permission to copy,
+distribute and/or modify the software.
+
+  Also, for each author's protection and ours, we want to make certain
+that everyone understands that there is no warranty for this free
+software.  If the software is modified by someone else and passed on, we
+want its recipients to know that what they have is not the original, so
+that any problems introduced by others will not reflect on the original
+authors' reputations.
+
+  Finally, any free program is threatened constantly by software
+patents.  We wish to avoid the danger that redistributors of a free
+program will individually obtain patent licenses, in effect making the
+program proprietary.  To prevent this, we have made it clear that any
+patent must be licensed for everyone's free use or not licensed at all.
+
+  The precise terms and conditions for copying, distribution and
+modification follow.
+
+                    GNU GENERAL PUBLIC LICENSE
+   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
+
+  0. This License applies to any program or other work which contains
+a notice placed by the copyright holder saying it may be distributed
+under the terms of this General Public License.  The "Program", below,
+refers to any such program or work, and a "work based on the Program"
+means either the Program or any derivative work under copyright law:
+that is to say, a work containing the Program or a portion of it,
+either verbatim or with modifications and/or translated into another
+language.  (Hereinafter, translation is included without limitation in
+the term "modification".)  Each licensee is addressed as "you".
+
+Activities other than copying, distribution and modification are not
+covered by this License; they are outside its scope.  The act of
+running the Program is not restricted, and the output from the Program
+is covered only if its contents constitute a work based on the
+Program (independent of having been made by running the Program).
+Whether that is true depends on what the Program does.
+
+  1. You may copy and distribute verbatim copies of the Program's
+source code as you receive it, in any medium, provided that you
+conspicuously and appropriately publish on each copy an appropriate
+copyright notice and disclaimer of warranty; keep intact all the
+notices that refer to this License and to the absence of any warranty;
+and give any other recipients of the Program a copy of this License
+along with the Program.
+
+You may charge a fee for the physical act of transferring a copy, and
+you may at your option offer warranty protection in exchange for a fee.
+
+  2. You may modify your copy or copies of the Program or any portion
+of it, thus forming a work based on the Program, and copy and
+distribute such modifications or work under the terms of Section 1
+above, provided that you also meet all of these conditions:
+
+    a) You must cause the modified files to carry prominent notices
+    stating that you changed the files and the date of any change.
+
+    b) You must cause any work that you distribute or publish, that in
+    whole or in part contains or is derived from the Program or any
+    part thereof, to be licensed as a whole at no charge to all third
+    parties under the terms of this License.
+
+    c) If the modified program normally reads commands interactively
+    when run, you must cause it, when started running for such
+    interactive use in the most ordinary way, to print or display an
+    announcement including an appropriate copyright notice and a
+    notice that there is no warranty (or else, saying that you provide
+    a warranty) and that users may redistribute the program under
+    these conditions, and telling the user how to view a copy of this
+    License.  (Exception: if the Program itself is interactive but
+    does not normally print such an announcement, your work based on
+    the Program is not required to print an announcement.)
+
+These requirements apply to the modified work as a whole.  If
+identifiable sections of that work are not derived from the Program,
+and can be reasonably considered independent and separate works in
+themselves, then this License, and its terms, do not apply to those
+sections when you distribute them as separate works.  But when you
+distribute the same sections as part of a whole which is a work based
+on the Program, the distribution of the whole must be on the terms of
+this License, whose permissions for other licensees extend to the
+entire whole, and thus to each and every part regardless of who wrote it.
+
+Thus, it is not the intent of this section to claim rights or contest
+your rights to work written entirely by you; rather, the intent is to
+exercise the right to control the distribution of derivative or
+collective works based on the Program.
+
+In addition, mere aggregation of another work not based on the Program
+with the Program (or with a work based on the Program) on a volume of
+a storage or distribution medium does not bring the other work under
+the scope of this License.
+
+  3. You may copy and distribute the Program (or a work based on it,
+under Section 2) in object code or executable form under the terms of
+Sections 1 and 2 above provided that you also do one of the following:
+
+    a) Accompany it with the complete corresponding machine-readable
+    source code, which must be distributed under the terms of Sections
+    1 and 2 above on a medium customarily used for software interchange; or,
+
+    b) Accompany it with a written offer, valid for at least three
+    years, to give any third party, for a charge no more than your
+    cost of physically performing source distribution, a complete
+    machine-readable copy of the corresponding source code, to be
+    distributed under the terms of Sections 1 and 2 above on a medium
+    customarily used for software interchange; or,
+
+    c) Accompany it with the information you received as to the offer
+    to distribute corresponding source code.  (This alternative is
+    allowed only for noncommercial distribution and only if you
+    received the program in object code or executable form with such
+    an offer, in accord with Subsection b above.)
+
+The source code for a work means the preferred form of the work for
+making modifications to it.  For an executable work, complete source
+code means all the source code for all modules it contains, plus any
+associated interface definition files, plus the scripts used to
+control compilation and installation of the executable.  However, as a
+special exception, the source code distributed need not include
+anything that is normally distributed (in either source or binary
+form) with the major components (compiler, kernel, and so on) of the
+operating system on which the executable runs, unless that component
+itself accompanies the executable.
+
+If distribution of executable or object code is made by offering
+access to copy from a designated place, then offering equivalent
+access to copy the source code from the same place counts as
+distribution of the source code, even though third parties are not
+compelled to copy the source along with the object code.
+
+  4. You may not copy, modify, sublicense, or distribute the Program
+except as expressly provided under this License.  Any attempt
+otherwise to copy, modify, sublicense or distribute the Program is
+void, and will automatically terminate your rights under this License.
+However, parties who have received copies, or rights, from you under
+this License will not have their licenses terminated so long as such
+parties remain in full compliance.
+
+  5. You are not required to accept this License, since you have not
+signed it.  However, nothing else grants you permission to modify or
+distribute the Program or its derivative works.  These actions are
+prohibited by law if you do not accept this License.  Therefore, by
+modifying or distributing the Program (or any work based on the
+Program), you indicate your acceptance of this License to do so, and
+all its terms and conditions for copying, distributing or modifying
+the Program or works based on it.
+
+  6. Each time you redistribute the Program (or any work based on the
+Program), the recipient automatically receives a license from the
+original licensor to copy, distribute or modify the Program subject to
+these terms and conditions.  You may not impose any further
+restrictions on the recipients' exercise of the rights granted herein.
+You are not responsible for enforcing compliance by third parties to
+this License.
+
+  7. If, as a consequence of a court judgment or allegation of patent
+infringement or for any other reason (not limited to patent issues),
+conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License.  If you cannot
+distribute so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you
+may not distribute the Program at all.  For example, if a patent
+license would not permit royalty-free redistribution of the Program by
+all those who receive copies directly or indirectly through you, then
+the only way you could satisfy both it and this License would be to
+refrain entirely from distribution of the Program.
+
+If any portion of this section is held invalid or unenforceable under
+any particular circumstance, the balance of the section is intended to
+apply and the section as a whole is intended to apply in other
+circumstances.
+
+It is not the purpose of this section to induce you to infringe any
+patents or other property right claims or to contest validity of any
+such claims; this section has the sole purpose of protecting the
+integrity of the free software distribution system, which is
+implemented by public license practices.  Many people have made
+generous contributions to the wide range of software distributed
+through that system in reliance on consistent application of that
+system; it is up to the author/donor to decide if he or she is willing
+to distribute software through any other system and a licensee cannot
+impose that choice.
+
+This section is intended to make thoroughly clear what is believed to
+be a consequence of the rest of this License.
+
+  8. If the distribution and/or use of the Program is restricted in
+certain countries either by patents or by copyrighted interfaces, the
+original copyright holder who places the Program under this License
+may add an explicit geographical distribution limitation excluding
+those countries, so that distribution is permitted only in or among
+countries not thus excluded.  In such case, this License incorporates
+the limitation as if written in the body of this License.
+
+  9. The Free Software Foundation may publish revised and/or new versions
+of the General Public License from time to time.  Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+Each version is given a distinguishing version number.  If the Program
+specifies a version number of this License which applies to it and "any
+later version", you have the option of following the terms and conditions
+either of that version or of any later version published by the Free
+Software Foundation.  If the Program does not specify a version number of
+this License, you may choose any version ever published by the Free Software
+Foundation.
+
+  10. If you wish to incorporate parts of the Program into other free
+programs whose distribution conditions are different, write to the author
+to ask for permission.  For software which is copyrighted by the Free
+Software Foundation, write to the Free Software Foundation; we sometimes
+make exceptions for this.  Our decision will be guided by the two goals
+of preserving the free status of all derivatives of our free software and
+of promoting the sharing and reuse of software generally.
+
+                            NO WARRANTY
+
+  11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
+FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
+OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
+PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
+OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
+TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
+PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
+REPAIR OR CORRECTION.
+
+  12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
+REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
+INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
+OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
+TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
+YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
+PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGES.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+convey the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+Also add information on how to contact you by electronic and paper mail.
+
+If the program is interactive, make it output a short notice like this
+when it starts in an interactive mode:
+
+    Gnomovision version 69, Copyright (C) year name of author
+    Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, the commands you use may
+be called something other than `show w' and `show c'; they could even be
+mouse-clicks or menu items--whatever suits your program.
+
+You should also get your employer (if you work as a programmer) or your
+school, if any, to sign a "copyright disclaimer" for the program, if
+necessary.  Here is a sample; alter the names:
+
+  Yoyodyne, Inc., hereby disclaims all copyright interest in the program
+  `Gnomovision' (which makes passes at compilers) written by James Hacker.
+
+  <signature of Ty Coon>, 1 April 1989
+  Ty Coon, President of Vice
+
+This General Public License does not permit incorporating your program into
+proprietary programs.  If your program is a subroutine library, you may
+consider it more useful to permit linking proprietary applications with the
+library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..ae941fa
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,7 @@
+Copyright 2020 Jens Axboe
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..5d9c4dc
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,84 @@
+NAME=liburing
+SPECFILE=$(NAME).spec
+VERSION=$(shell awk '/Version:/ { print $$2 }' $(SPECFILE))
+TAG = $(NAME)-$(VERSION)
+RPMBUILD=$(shell `which rpmbuild >&/dev/null` && echo "rpmbuild" || echo "rpm")
+
+INSTALL=install
+
+default: all
+
+all:
+	@$(MAKE) -C src
+	@$(MAKE) -C test
+	@$(MAKE) -C examples
+
+.PHONY: all install default clean test
+.PHONY: FORCE cscope
+
+partcheck: all
+	@echo "make partcheck => TODO add tests with out kernel support"
+
+runtests: all
+	@$(MAKE) -C test runtests
+runtests-loop:
+	@$(MAKE) -C test runtests-loop
+
+config-host.mak: configure
+	@if [ ! -e "$@" ]; then					\
+	  echo "Running configure ...";				\
+	  ./configure;						\
+	else							\
+	  echo "$@ is out-of-date, running configure";		\
+	  sed -n "/.*Configured with/s/[^:]*: //p" "$@" | sh;	\
+	fi
+
+ifneq ($(MAKECMDGOALS),clean)
+include config-host.mak
+endif
+
+%.pc: %.pc.in config-host.mak $(SPECFILE)
+	sed -e "s%@prefix@%$(prefix)%g" \
+	    -e "s%@libdir@%$(libdir)%g" \
+	    -e "s%@includedir@%$(includedir)%g" \
+	    -e "s%@NAME@%$(NAME)%g" \
+	    -e "s%@VERSION@%$(VERSION)%g" \
+	    $< >$@
+
+install: $(NAME).pc
+	@$(MAKE) -C src install prefix=$(DESTDIR)$(prefix) \
+		includedir=$(DESTDIR)$(includedir) \
+		libdir=$(DESTDIR)$(libdir) \
+		libdevdir=$(DESTDIR)$(libdevdir) \
+		relativelibdir=$(relativelibdir)
+	$(INSTALL) -D -m 644 $(NAME).pc $(DESTDIR)$(libdevdir)/pkgconfig/$(NAME).pc
+	$(INSTALL) -m 755 -d $(DESTDIR)$(mandir)/man2
+	$(INSTALL) -m 644 man/*.2 $(DESTDIR)$(mandir)/man2
+	$(INSTALL) -m 755 -d $(DESTDIR)$(mandir)/man3
+	$(INSTALL) -m 644 man/*.3 $(DESTDIR)$(mandir)/man3
+	$(INSTALL) -m 755 -d $(DESTDIR)$(mandir)/man7
+	$(INSTALL) -m 644 man/*.7 $(DESTDIR)$(mandir)/man7
+
+install-tests:
+	@$(MAKE) -C test install prefix=$(DESTDIR)$(prefix) datadir=$(DESTDIR)$(datadir)
+
+clean:
+	@rm -f config-host.mak config-host.h cscope.out $(NAME).pc test/*.dmesg
+	@$(MAKE) -C src clean
+	@$(MAKE) -C test clean
+	@$(MAKE) -C examples clean
+
+cscope:
+	@cscope -b -R
+
+tag-archive:
+	@git tag $(TAG)
+
+create-archive:
+	@git archive --prefix=$(NAME)-$(VERSION)/ -o $(NAME)-$(VERSION).tar.gz $(TAG)
+	@echo "The final archive is ./$(NAME)-$(VERSION).tar.gz."
+
+archive: clean tag-archive create-archive
+
+srpm: create-archive
+	$(RPMBUILD) --define "_sourcedir `pwd`" --define "_srcrpmdir `pwd`" --nodeps -bs $(SPECFILE)
diff --git a/Makefile.quiet b/Makefile.quiet
new file mode 100644
index 0000000..906d22b
--- /dev/null
+++ b/Makefile.quiet
@@ -0,0 +1,11 @@
+ifneq ($(findstring $(MAKEFLAGS),s),s)
+ifndef V
+	QUIET_CC	= @echo '    '   CC $@;
+	QUIET_CXX	= @echo '    '  CXX $@;
+	QUIET_LINK	= @echo '  '   LINK $@;
+	QUIET_AR	= @echo '    '   AR $@;
+	QUIET_RANLIB	= @echo '' RANLIB $@;
+endif
+endif
+
+
diff --git a/README b/README
new file mode 100644
index 0000000..a76021e
--- /dev/null
+++ b/README
@@ -0,0 +1,46 @@
+liburing
+--------
+
+This is the io_uring library, liburing. liburing provides helpers to setup and
+teardown io_uring instances, and also a simplified interface for
+applications that don't need (or want) to deal with the full kernel
+side implementation.
+
+For more info on io_uring, please see:
+
+https://kernel.dk/io_uring.pdf
+
+Subscribe to io-uring@vger.kernel.org for io_uring related discussions
+and development for both kernel and userspace. The list is archived here:
+
+https://lore.kernel.org/io-uring/
+
+
+ulimit settings
+---------------
+
+io_uring accounts memory it needs under the rlimit memlocked option, which
+can be quite low on some setups (64K). The default is usually enough for
+most use cases, but bigger rings or things like registered buffers deplete
+it quickly. root isn't under this restriction, but regular users are. Going
+into detail on how to bump the limit on various systems is beyond the scope
+of this little blurb, but check /etc/security/limits.conf for user specific
+settings, or /etc/systemd/user.conf and /etc/systemd/system.conf for systemd
+setups.
+
+Regressions tests
+-----------------
+
+The bulk of liburing is actually regression/unit tests for both liburing and
+the kernel io_uring support. Please note that this suite isn't expected to
+pass on older kernels, and may even crash or hang older kernels!
+
+License
+-------
+
+All software contained within this repo is dual licensed LGPL and MIT, see
+COPYING and LICENSE, except for a header coming from the kernel which is
+dual licensed GPL with a Linux-syscall-note exception and MIT, see
+COPYING.GPL and <https://spdx.org/licenses/Linux-syscall-note.html>.
+
+Jens Axboe 2020-01-20
diff --git a/configure b/configure
new file mode 100755
index 0000000..3b96cde
--- /dev/null
+++ b/configure
@@ -0,0 +1,380 @@
+#!/bin/sh
+
+cc=${CC:-gcc}
+cxx=${CXX:-g++}
+
+for opt do
+  optarg=$(expr "x$opt" : 'x[^=]*=\(.*\)')
+  case "$opt" in
+  --help|-h) show_help=yes
+  ;;
+  --prefix=*) prefix="$optarg"
+  ;;
+  --includedir=*) includedir="$optarg"
+  ;;
+  --libdir=*) libdir="$optarg"
+  ;;
+  --libdevdir=*) libdevdir="$optarg"
+  ;;
+  --mandir=*) mandir="$optarg"
+  ;;
+  --datadir=*) datadir="$optarg"
+  ;;
+  --cc=*) cc="$optarg"
+  ;;
+  --cxx=*) cxx="$optarg"
+  ;;
+  *)
+    echo "ERROR: unknown option $opt"
+    echo "Try '$0 --help' for more information"
+    exit 1
+  ;;
+  esac
+done
+
+if test -z "$prefix"; then
+  prefix=/usr
+fi
+if test -z "$includedir"; then
+  includedir="$prefix/include"
+fi
+if test -z "$libdir"; then
+  libdir="$prefix/lib"
+fi
+if test -z "$libdevdir"; then
+  libdevdir="$prefix/lib"
+fi
+if test -z "$mandir"; then
+  mandir="$prefix/man"
+fi
+if test -z "$datadir"; then
+  datadir="$prefix/share"
+fi
+
+if test x"$libdir" = x"$libdevdir"; then
+  relativelibdir=""
+else
+  relativelibdir="$libdir/"
+fi
+
+if test "$show_help" = "yes"; then
+cat <<EOF
+
+Usage: configure [options]
+Options: [defaults in brackets after descriptions]
+  --help                   print this message
+  --prefix=PATH            install in PATH [$prefix]
+  --includedir=PATH        install headers in PATH [$includedir]
+  --libdir=PATH            install runtime libraries in PATH [$libdir]
+  --libdevdir=PATH         install development libraries in PATH [$libdevdir]
+  --mandir=PATH            install man pages in PATH [$mandir]
+  --datadir=PATH           install shared data in PATH [$datadir]
+EOF
+exit 0
+fi
+
+TMPC="$(mktemp --tmpdir fio-conf-XXXXXXXXXX.c)"
+TMPC2="$(mktemp --tmpdir fio-conf-XXXXXXXXXX-2.c)"
+TMPO="$(mktemp --tmpdir fio-conf-XXXXXXXXXX.o)"
+TMPE="$(mktemp --tmpdir fio-conf-XXXXXXXXXX.exe)"
+
+# NB: do not call "exit" in the trap handler; this is buggy with some shells;
+# see <1285349658-3122-1-git-send-email-loic.minier@linaro.org>
+trap "rm -f $TMPC $TMPC2 $TMPO $TMPE" EXIT INT QUIT TERM
+
+rm -rf config.log
+
+config_host_mak="config-host.mak"
+config_host_h="config-host.h"
+
+rm -rf $config_host_mak
+rm -rf $config_host_h
+
+fatal() {
+  echo $@
+  echo "Configure failed, check config.log and/or the above output"
+  rm -rf $config_host_mak
+  rm -rf $config_host_h
+  exit 1
+}
+
+# Print result for each configuration test
+print_config() {
+  printf "%-30s%s\n" "$1" "$2"
+}
+
+# Default CFLAGS
+CFLAGS="-D_GNU_SOURCE -include config-host.h"
+BUILD_CFLAGS=""
+
+# Print configure header at the top of $config_host_h
+echo "/*" > $config_host_h
+echo " * Automatically generated by configure - do not modify" >> $config_host_h
+printf " * Configured with:" >> $config_host_h
+printf " * '%s'" "$0" "$@" >> $config_host_h
+echo "" >> $config_host_h
+echo " */" >> $config_host_h
+
+echo "# Automatically generated by configure - do not modify" > $config_host_mak
+printf "# Configured with:" >> $config_host_mak
+printf " '%s'" "$0" "$@" >> $config_host_mak
+echo >> $config_host_mak
+
+do_cxx() {
+    # Run the compiler, capturing its output to the log.
+    echo $cxx "$@" >> config.log
+    $cxx "$@" >> config.log 2>&1 || return $?
+    return 0
+}
+
+do_cc() {
+    # Run the compiler, capturing its output to the log.
+    echo $cc "$@" >> config.log
+    $cc "$@" >> config.log 2>&1 || return $?
+    # Test passed. If this is an --enable-werror build, rerun
+    # the test with -Werror and bail out if it fails. This
+    # makes warning-generating-errors in configure test code
+    # obvious to developers.
+    if test "$werror" != "yes"; then
+        return 0
+    fi
+    # Don't bother rerunning the compile if we were already using -Werror
+    case "$*" in
+        *-Werror*)
+           return 0
+        ;;
+    esac
+    echo $cc -Werror "$@" >> config.log
+    $cc -Werror "$@" >> config.log 2>&1 && return $?
+    echo "ERROR: configure test passed without -Werror but failed with -Werror."
+    echo "This is probably a bug in the configure script. The failing command"
+    echo "will be at the bottom of config.log."
+    fatal "You can run configure with --disable-werror to bypass this check."
+}
+
+compile_prog() {
+  local_cflags="$1"
+  local_ldflags="$2 $LIBS"
+  echo "Compiling test case $3" >> config.log
+  do_cc $CFLAGS $local_cflags -o $TMPE $TMPC $LDFLAGS $local_ldflags
+}
+
+compile_prog_cxx() {
+  local_cflags="$1"
+  local_ldflags="$2 $LIBS"
+  echo "Compiling test case $3" >> config.log
+  do_cxx $CFLAGS $local_cflags -o $TMPE $TMPC $LDFLAGS $local_ldflags
+}
+
+has() {
+  type "$1" >/dev/null 2>&1
+}
+
+output_mak() {
+  echo "$1=$2" >> $config_host_mak
+}
+
+output_sym() {
+  output_mak "$1" "y"
+  echo "#define $1" >> $config_host_h
+}
+
+print_and_output_mak() {
+  print_config "$1" "$2"
+  output_mak "$1" "$2"
+}
+print_and_output_mak "prefix" "$prefix"
+print_and_output_mak "includedir" "$includedir"
+print_and_output_mak "libdir" "$libdir"
+print_and_output_mak "libdevdir" "$libdevdir"
+print_and_output_mak "relativelibdir" "$relativelibdir"
+print_and_output_mak "mandir" "$mandir"
+print_and_output_mak "datadir" "$datadir"
+
+##########################################
+# check for __kernel_rwf_t
+__kernel_rwf_t="no"
+cat > $TMPC << EOF
+#include <linux/fs.h>
+int main(int argc, char **argv)
+{
+  __kernel_rwf_t x;
+  x = 0;
+  return x;
+}
+EOF
+if compile_prog "" "" "__kernel_rwf_t"; then
+  __kernel_rwf_t="yes"
+fi
+print_config "__kernel_rwf_t" "$__kernel_rwf_t"
+
+##########################################
+# check for __kernel_timespec
+__kernel_timespec="no"
+cat > $TMPC << EOF
+#include <linux/time.h>
+#include <linux/time_types.h>
+int main(int argc, char **argv)
+{
+  struct __kernel_timespec ts;
+  ts.tv_sec = 0;
+  ts.tv_nsec = 1;
+  return 0;
+}
+EOF
+if compile_prog "" "" "__kernel_timespec"; then
+  __kernel_timespec="yes"
+fi
+print_config "__kernel_timespec" "$__kernel_timespec"
+
+##########################################
+# check for open_how
+open_how="no"
+cat > $TMPC << EOF
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <string.h>
+int main(int argc, char **argv)
+{
+  struct open_how how;
+  how.flags = 0;
+  how.mode = 0;
+  how.resolve = 0;
+  return 0;
+}
+EOF
+if compile_prog "" "" "open_how"; then
+  open_how="yes"
+fi
+print_config "open_how" "$open_how"
+
+##########################################
+# check for statx
+statx="no"
+cat > $TMPC << EOF
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <linux/stat.h>
+int main(int argc, char **argv)
+{
+  struct statx x;
+
+  return memset(&x, 0, sizeof(x)) != NULL;
+}
+EOF
+if compile_prog "" "" "statx"; then
+  statx="yes"
+fi
+print_config "statx" "$statx"
+
+##########################################
+# check for C++
+has_cxx="no"
+cat > $TMPC << EOF
+#include <iostream>
+int main(int argc, char **argv)
+{
+  std::cout << "Test";
+  return 0;
+}
+EOF
+if compile_prog_cxx "" "" "C++"; then
+  has_cxx="yes"
+fi
+print_config "C++" "$has_cxx"
+
+##########################################
+# check for ucontext support
+has_ucontext="no"
+cat > $TMPC << EOF
+#include <ucontext.h>
+int main(int argc, char **argv)
+{
+  ucontext_t ctx;
+  getcontext(&ctx);
+  return 0;
+}
+EOF
+if compile_prog "" "" "has_ucontext"; then
+  has_ucontext="yes"
+fi
+print_config "has_ucontext" "$has_ucontext"
+
+
+#############################################################################
+
+if test "$__kernel_rwf_t" = "yes"; then
+  output_sym "CONFIG_HAVE_KERNEL_RWF_T"
+fi
+if test "$__kernel_timespec" = "yes"; then
+  output_sym "CONFIG_HAVE_KERNEL_TIMESPEC"
+fi
+if test "$open_how" = "yes"; then
+  output_sym "CONFIG_HAVE_OPEN_HOW"
+fi
+if test "$statx" = "yes"; then
+  output_sym "CONFIG_HAVE_STATX"
+fi
+if test "$has_cxx" = "yes"; then
+  output_sym "CONFIG_HAVE_CXX"
+fi
+if test "$has_ucontext" = "yes"; then
+  output_sym "CONFIG_HAVE_UCONTEXT"
+fi
+
+echo "CC=$cc" >> $config_host_mak
+print_config "CC" "$cc"
+echo "CXX=$cxx" >> $config_host_mak
+print_config "CXX" "$cxx"
+
+# generate compat.h
+compat_h="src/include/liburing/compat.h"
+cat > $compat_h << EOF
+/* SPDX-License-Identifier: MIT */
+#ifndef LIBURING_COMPAT_H
+#define LIBURING_COMPAT_H
+
+EOF
+
+if test "$__kernel_rwf_t" != "yes"; then
+cat >> $compat_h << EOF
+typedef int __kernel_rwf_t;
+
+EOF
+fi
+if test "$__kernel_timespec" != "yes"; then
+cat >> $compat_h << EOF
+#include <stdint.h>
+
+struct __kernel_timespec {
+	int64_t		tv_sec;
+	long long	tv_nsec;
+};
+
+EOF
+else
+cat >> $compat_h << EOF
+#include <linux/time_types.h>
+
+EOF
+fi
+if test "$open_how" != "yes"; then
+cat >> $compat_h << EOF
+#include <inttypes.h>
+
+struct open_how {
+	uint64_t	flags;
+	uint64_t	mode;
+	uint64_t	resolve;
+};
+
+EOF
+fi
+
+cat >> $compat_h << EOF
+#endif
+EOF
diff --git a/debian/README.Debian b/debian/README.Debian
new file mode 100644
index 0000000..15b9fd0
--- /dev/null
+++ b/debian/README.Debian
@@ -0,0 +1,7 @@
+liburing for Debian
+
+The newest Linux IO interface i.e. io_uring, need
+userspace library to support it. This package
+liburing is the library for io_uring.
+
+ -- Liu Changcheng <changcheng.liu@aliyun.com>  Thu, 14 Nov 2019 21:35:39 +0800
diff --git a/debian/changelog b/debian/changelog
new file mode 100644
index 0000000..f0032e3
--- /dev/null
+++ b/debian/changelog
@@ -0,0 +1,27 @@
+liburing (0.7-1) stable; urgency=low
+
+  * Update to 0.7
+  * Fix library symlinks
+
+ -- Stefan Metzmacher <metze@samba.org>  Thu, 23 Jul 2020 00:23:00 +0200
+
+liburing (0.4-2) stable; urgency=low
+
+  * Fix /usr/lib/*/liburing.so symlink to /lib/*/liburing.so.1.0.4
+
+ -- Stefan Metzmacher <metze@samba.org>  Fri, 07 Feb 2020 15:30:00 +0100
+
+liburing (0.4-1) stable; urgency=low
+
+  * Package liburing-0.4 using a packaging layout similar to libaio1
+
+ -- Stefan Metzmacher <metze@samba.org>  Thu, 06 Feb 2020 11:30:00 +0100
+
+liburing (0.2-1ubuntu1) stable; urgency=low
+
+  * Initial release.
+  * commit 4bce856d43ab1f9a64477aa5a8f9f02f53e64b74
+  *	 Author: Jens Axboe <axboe@kernel.dk>
+  *	 Date:   Mon Nov 11 16:00:58 2019 -0700
+
+ -- Liu Changcheng <changcheng.liu@aliyun.com>  Fri, 15 Nov 2019 00:06:46 +0800
diff --git a/debian/compat b/debian/compat
new file mode 100644
index 0000000..ec63514
--- /dev/null
+++ b/debian/compat
@@ -0,0 +1 @@
+9
diff --git a/debian/control b/debian/control
new file mode 100644
index 0000000..831a314
--- /dev/null
+++ b/debian/control
@@ -0,0 +1,48 @@
+Source: liburing
+Section: libs
+Priority: optional
+Maintainer: Liu Changcheng <changcheng.liu@intel.com>
+Build-Depends: debhelper (>=9)
+Standards-Version: 4.1.4
+Homepage: https://git.kernel.dk/cgit/liburing/tree/README
+Vcs-Git: https://git.kernel.dk/liburing
+Vcs-Browser: https://git.kernel.dk/cgit/liburing/
+
+Package: liburing1
+Architecture: linux-any
+Multi-Arch: same
+Pre-Depends: ${misc:Pre-Depends}
+Depends: ${misc:Depends}, ${shlibs:Depends}
+Description: userspace library for using io_uring
+ io_uring is kernel feature to improve development
+ The newese Linux IO interface, io_uring could improve
+ system performance a lot. liburing is the userpace
+ library to use io_uring feature.
+ .
+ This package contains the shared library.
+
+Package: liburing1-udeb
+Package-Type: udeb
+Section: debian-installer
+Architecture: linux-any
+Depends: ${misc:Depends}, ${shlibs:Depends},
+Description: userspace library for using io_uring
+ io_uring is kernel feature to improve development
+ The newese Linux IO interface, io_uring could improve
+ system performance a lot. liburing is the userpace
+ library to use io_uring feature.
+ .
+ This package contains the udeb shared library.
+
+Package: liburing-dev
+Section: libdevel
+Architecture: linux-any
+Multi-Arch: same
+Depends: ${misc:Depends}, liburing1 (= ${binary:Version}),
+Description: userspace library for using io_uring
+ io_uring is kernel feature to improve development
+ The newese Linux IO interface, io_uring could improve
+ system performance a lot. liburing is the userpace
+ library to use io_uring feature.
+ .
+ This package contains the static library and the header files.
diff --git a/debian/copyright b/debian/copyright
new file mode 100644
index 0000000..0b3f3eb
--- /dev/null
+++ b/debian/copyright
@@ -0,0 +1,49 @@
+Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
+Upstream-Name: liburing
+Source: https://git.kernel.dk/cgit/liburing/
+
+Files: *
+Copyright: 2019 Jens Axboe <axboe@kernel.dk>
+License: GPL-2+ / MIT
+
+Files: debian/*
+Copyright: 2019 Changcheng Liu <changcheng.liu@aliyun.com>
+License: GPL-2+
+
+License: GPL-2+
+ This package is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+ .
+ This package is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+ .
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>
+ .
+ On Debian systems, the complete text of the GNU General
+ Public License version 2 can be found in "/usr/share/common-licenses/GPL-2".
+
+License: MIT
+ Copyright 2020 Jens Axboe
+
+ Permission is hereby granted, free of charge, to any person obtaining a copy
+ of this software and associated documentation files (the "Software"), to deal
+ in the Software without restriction, including without limitation the rights
+ to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ copies of the Software, and to permit persons to whom the Software is
+ furnished to do so, subject to the following conditions:
+
+ The above copyright notice and this permission notice shall be included in all
+ copies or substantial portions of the Software.
+
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ SOFTWARE.
diff --git a/debian/liburing-dev.install b/debian/liburing-dev.install
new file mode 100644
index 0000000..a00d956
--- /dev/null
+++ b/debian/liburing-dev.install
@@ -0,0 +1,4 @@
+usr/include
+usr/lib/*/lib*.so
+usr/lib/*/lib*.a
+usr/lib/*/pkgconfig
diff --git a/debian/liburing-dev.manpages b/debian/liburing-dev.manpages
new file mode 100644
index 0000000..fbbee23
--- /dev/null
+++ b/debian/liburing-dev.manpages
@@ -0,0 +1,6 @@
+man/io_uring_setup.2
+man/io_uring_enter.2
+man/io_uring_register.2
+man/io_uring_queue_exit.3
+man/io_uring_queue_init.3
+man/io_uring_get_sqe.3
diff --git a/debian/liburing1-udeb.install b/debian/liburing1-udeb.install
new file mode 100644
index 0000000..622f9ef
--- /dev/null
+++ b/debian/liburing1-udeb.install
@@ -0,0 +1 @@
+lib/*/lib*.so.*
diff --git a/debian/liburing1.install b/debian/liburing1.install
new file mode 100644
index 0000000..622f9ef
--- /dev/null
+++ b/debian/liburing1.install
@@ -0,0 +1 @@
+lib/*/lib*.so.*
diff --git a/debian/liburing1.symbols b/debian/liburing1.symbols
new file mode 100644
index 0000000..29109f2
--- /dev/null
+++ b/debian/liburing1.symbols
@@ -0,0 +1,32 @@
+liburing.so.1 liburing1 #MINVER#
+ (symver)LIBURING_0.1 0.1-1
+ io_uring_get_sqe@LIBURING_0.1 0.1-1
+ io_uring_queue_exit@LIBURING_0.1 0.1-1
+ io_uring_queue_init@LIBURING_0.1 0.1-1
+ io_uring_queue_mmap@LIBURING_0.1 0.1-1
+ io_uring_register_buffers@LIBURING_0.1 0.1-1
+ io_uring_register_eventfd@LIBURING_0.1 0.1-1
+ io_uring_register_eventfd_async@LIBURING_0.6 0.6-1
+ io_uring_register_files@LIBURING_0.1 0.1-1
+ io_uring_submit@LIBURING_0.1 0.1-1
+ io_uring_submit_and_wait@LIBURING_0.1 0.1-1
+ io_uring_unregister_buffers@LIBURING_0.1 0.1-1
+ io_uring_unregister_files@LIBURING_0.1 0.1-1
+ (symver)LIBURING_0.2 0.2-1
+ __io_uring_get_cqe@LIBURING_0.2 0.2-1
+ io_uring_queue_init_params@LIBURING_0.2 0.2-1
+ io_uring_register_files_update@LIBURING_0.2 0.2-1
+ io_uring_peek_batch_cqe@LIBURING_0.2 0.2-1
+ io_uring_wait_cqe_timeout@LIBURING_0.2 0.2-1
+ io_uring_wait_cqes@LIBURING_0.2 0.2-1
+ (symver)LIBURING_0.3 0.3-1
+ (symver)LIBURING_0.4 0.4-1
+ (symver)LIBURING_0.5 0.5-1
+ (symver)LIBURING_0.6 0.6-1
+ (symver)LIBURING_0.7 0.7-1
+ io_uring_get_probe@LIBURING_0.4 0.4-1
+ io_uring_get_probe_ring@LIBURING_0.4 0.4-1
+ io_uring_register_personality@LIBURING_0.4 0.4-1
+ io_uring_register_probe@LIBURING_0.4 0.4-1
+ io_uring_ring_dontfork@LIBURING_0.4 0.4-1
+ io_uring_unregister_personality@LIBURING_0.4 0.4-1
diff --git a/debian/patches/series b/debian/patches/series
new file mode 100644
index 0000000..4a97dfa
--- /dev/null
+++ b/debian/patches/series
@@ -0,0 +1 @@
+# You must remove unused comment lines for the released package.
diff --git a/debian/rules b/debian/rules
new file mode 100755
index 0000000..1a334b3
--- /dev/null
+++ b/debian/rules
@@ -0,0 +1,81 @@
+#!/usr/bin/make -f
+
+# Uncomment this to turn on verbose mode.
+#export DH_VERBOSE=1
+
+DEB_BUILD_MAINT_OPTIONS = hardening=+bindnow
+DEB_CFLAGS_MAINT_PREPEND = -Wall
+
+include /usr/share/dpkg/default.mk
+include /usr/share/dpkg/buildtools.mk
+
+export CC
+
+lib := liburing1
+libdbg := $(lib)-dbg
+libudeb := $(lib)-udeb
+libdev := liburing-dev
+
+build-indep:
+
+build-arch:
+	dh_testdir
+
+	$(MAKE) CPPFLAGS="$(CPPFLAGS)" CFLAGS="$(CFLAGS)" LDFLAGS="$(LDFLAGS)"
+
+build: build-indep build-arch
+
+clean:
+	dh_testdir
+	dh_testroot
+
+	$(MAKE) clean
+
+	dh_clean
+
+check-arch: build-arch
+	dh_testdir
+
+ifeq (,$(filter nocheck,$(DEB_BUILD_OPTIONS)))
+	$(MAKE) CPPFLAGS="$(CPPFLAGS)" CFLAGS="$(CFLAGS)" LDFLAGS="$(LDFLAGS)" \
+	        partcheck
+endif
+
+install-arch: check-arch
+	dh_testdir
+	dh_testroot
+	dh_clean
+	dh_installdirs
+
+	$(MAKE) install \
+	  DESTDIR=$(CURDIR)/debian/tmp \
+	  libdir=/lib/$(DEB_HOST_MULTIARCH) \
+	  libdevdir=/usr/lib/$(DEB_HOST_MULTIARCH) \
+	  relativelibdir=/lib/$(DEB_HOST_MULTIARCH)/
+
+binary: binary-indep binary-arch
+
+binary-indep:
+	# Nothing to do.
+
+binary-arch: install-arch
+	dh_testdir
+	dh_testroot
+	dh_install -a
+	dh_installdocs -a
+	dh_installexamples -a
+	dh_installman -a
+	dh_lintian -a
+	dh_link -a
+	dh_strip -a --ddeb-migration='$(libdbg) (<< 0.3)'
+	dh_compress -a
+	dh_fixperms -a
+	dh_makeshlibs -a --add-udeb '$(libudeb)'
+	dh_shlibdeps -a
+	dh_installdeb -a
+	dh_gencontrol -a
+	dh_md5sums -a
+	dh_builddeb -a
+
+.PHONY: clean build-indep build-arch build
+.PHONY: install-arch binary-indep binary-arch binary
diff --git a/debian/source/format b/debian/source/format
new file mode 100644
index 0000000..163aaf8
--- /dev/null
+++ b/debian/source/format
@@ -0,0 +1 @@
+3.0 (quilt)
diff --git a/debian/source/local-options b/debian/source/local-options
new file mode 100644
index 0000000..00131ee
--- /dev/null
+++ b/debian/source/local-options
@@ -0,0 +1,2 @@
+#abort-on-upstream-changes
+#unapply-patches
diff --git a/debian/source/options b/debian/source/options
new file mode 100644
index 0000000..51da836
--- /dev/null
+++ b/debian/source/options
@@ -0,0 +1 @@
+extend-diff-ignore = "(^|/)(config\.log|config-host\.h|config-host\.mak|liburing\.pc)$"
diff --git a/debian/watch b/debian/watch
new file mode 100644
index 0000000..f0e30c4
--- /dev/null
+++ b/debian/watch
@@ -0,0 +1,3 @@
+# Site          Directory               Pattern                 Version Script
+version=4
+https://git.kernel.dk/cgit/liburing/ snapshot\/liburing-([\d\.]+)\.tar\.(?:gz|xz) debian uupdate
diff --git a/examples/Makefile b/examples/Makefile
new file mode 100644
index 0000000..60c1b71
--- /dev/null
+++ b/examples/Makefile
@@ -0,0 +1,29 @@
+CPPFLAGS ?=
+override CPPFLAGS += -D_GNU_SOURCE -I../src/include/
+CFLAGS ?= -g -O2
+XCFLAGS =
+override CFLAGS += -Wall -L../src/
+
+include ../Makefile.quiet
+
+ifneq ($(MAKECMDGOALS),clean)
+include ../config-host.mak
+endif
+
+all_targets += io_uring-test io_uring-cp link-cp
+
+ifdef CONFIG_HAVE_UCONTEXT
+all_targets += ucontext-cp
+endif
+
+all: $(all_targets)
+
+test_srcs := io_uring-test.c io_uring-cp.c link-cp.c
+
+test_objs := $(patsubst %.c,%.ol,$(test_srcs))
+
+%: %.c
+	$(QUIET_CC)$(CC) $(CPPFLAGS) $(CFLAGS) -o $@ $< -luring $(XCFLAGS)
+
+clean:
+	@rm -f $(all_targets) $(test_objs)
diff --git a/examples/io_uring-cp.c b/examples/io_uring-cp.c
new file mode 100644
index 0000000..2a44c30
--- /dev/null
+++ b/examples/io_uring-cp.c
@@ -0,0 +1,279 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * gcc -Wall -O2 -D_GNU_SOURCE -o io_uring-cp io_uring-cp.c -luring
+ */
+#include <stdio.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <assert.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include "liburing.h"
+
+#define QD	64
+#define BS	(32*1024)
+
+static int infd, outfd;
+
+struct io_data {
+	int read;
+	off_t first_offset, offset;
+	size_t first_len;
+	struct iovec iov;
+};
+
+static int setup_context(unsigned entries, struct io_uring *ring)
+{
+	int ret;
+
+	ret = io_uring_queue_init(entries, ring, 0);
+	if (ret < 0) {
+		fprintf(stderr, "queue_init: %s\n", strerror(-ret));
+		return -1;
+	}
+
+	return 0;
+}
+
+static int get_file_size(int fd, off_t *size)
+{
+	struct stat st;
+
+	if (fstat(fd, &st) < 0)
+		return -1;
+	if (S_ISREG(st.st_mode)) {
+		*size = st.st_size;
+		return 0;
+	} else if (S_ISBLK(st.st_mode)) {
+		unsigned long long bytes;
+
+		if (ioctl(fd, BLKGETSIZE64, &bytes) != 0)
+			return -1;
+
+		*size = bytes;
+		return 0;
+	}
+
+	return -1;
+}
+
+static void queue_prepped(struct io_uring *ring, struct io_data *data)
+{
+	struct io_uring_sqe *sqe;
+
+	sqe = io_uring_get_sqe(ring);
+	assert(sqe);
+
+	if (data->read)
+		io_uring_prep_readv(sqe, infd, &data->iov, 1, data->offset);
+	else
+		io_uring_prep_writev(sqe, outfd, &data->iov, 1, data->offset);
+
+	io_uring_sqe_set_data(sqe, data);
+}
+
+static int queue_read(struct io_uring *ring, off_t size, off_t offset)
+{
+	struct io_uring_sqe *sqe;
+	struct io_data *data;
+
+	data = malloc(size + sizeof(*data));
+	if (!data)
+		return 1;
+
+	sqe = io_uring_get_sqe(ring);
+	if (!sqe) {
+		free(data);
+		return 1;
+	}
+
+	data->read = 1;
+	data->offset = data->first_offset = offset;
+
+	data->iov.iov_base = data + 1;
+	data->iov.iov_len = size;
+	data->first_len = size;
+
+	io_uring_prep_readv(sqe, infd, &data->iov, 1, offset);
+	io_uring_sqe_set_data(sqe, data);
+	return 0;
+}
+
+static void queue_write(struct io_uring *ring, struct io_data *data)
+{
+	data->read = 0;
+	data->offset = data->first_offset;
+
+	data->iov.iov_base = data + 1;
+	data->iov.iov_len = data->first_len;
+
+	queue_prepped(ring, data);
+	io_uring_submit(ring);
+}
+
+static int copy_file(struct io_uring *ring, off_t insize)
+{
+	unsigned long reads, writes;
+	struct io_uring_cqe *cqe;
+	off_t write_left, offset;
+	int ret;
+
+	write_left = insize;
+	writes = reads = offset = 0;
+
+	while (insize || write_left) {
+		int had_reads, got_comp;
+	
+		/*
+		 * Queue up as many reads as we can
+		 */
+		had_reads = reads;
+		while (insize) {
+			off_t this_size = insize;
+
+			if (reads + writes >= QD)
+				break;
+			if (this_size > BS)
+				this_size = BS;
+			else if (!this_size)
+				break;
+
+			if (queue_read(ring, this_size, offset))
+				break;
+
+			insize -= this_size;
+			offset += this_size;
+			reads++;
+		}
+
+		if (had_reads != reads) {
+			ret = io_uring_submit(ring);
+			if (ret < 0) {
+				fprintf(stderr, "io_uring_submit: %s\n", strerror(-ret));
+				break;
+			}
+		}
+
+		/*
+		 * Queue is full at this point. Find at least one completion.
+		 */
+		got_comp = 0;
+		while (write_left) {
+			struct io_data *data;
+
+			if (!got_comp) {
+				ret = io_uring_wait_cqe(ring, &cqe);
+				got_comp = 1;
+			} else {
+				ret = io_uring_peek_cqe(ring, &cqe);
+				if (ret == -EAGAIN) {
+					cqe = NULL;
+					ret = 0;
+				}
+			}
+			if (ret < 0) {
+				fprintf(stderr, "io_uring_peek_cqe: %s\n",
+							strerror(-ret));
+				return 1;
+			}
+			if (!cqe)
+				break;
+
+			data = io_uring_cqe_get_data(cqe);
+			if (cqe->res < 0) {
+				if (cqe->res == -EAGAIN) {
+					queue_prepped(ring, data);
+					io_uring_cqe_seen(ring, cqe);
+					continue;
+				}
+				fprintf(stderr, "cqe failed: %s\n",
+						strerror(-cqe->res));
+				return 1;
+			} else if (cqe->res != data->iov.iov_len) {
+				/* Short read/write, adjust and requeue */
+				data->iov.iov_base += cqe->res;
+				data->iov.iov_len -= cqe->res;
+				data->offset += cqe->res;
+				queue_prepped(ring, data);
+				io_uring_cqe_seen(ring, cqe);
+				continue;
+			}
+
+			/*
+			 * All done. if write, nothing else to do. if read,
+			 * queue up corresponding write.
+			 */
+			if (data->read) {
+				queue_write(ring, data);
+				write_left -= data->first_len;
+				reads--;
+				writes++;
+			} else {
+				free(data);
+				writes--;
+			}
+			io_uring_cqe_seen(ring, cqe);
+		}
+	}
+
+	/* wait out pending writes */
+	while (writes) {
+		struct io_data *data;
+
+		ret = io_uring_wait_cqe(ring, &cqe);
+		if (ret) {
+			fprintf(stderr, "wait_cqe=%d\n", ret);
+			return 1;
+		}
+		if (cqe->res < 0) {
+			fprintf(stderr, "write res=%d\n", cqe->res);
+			return 1;
+		}
+		data = io_uring_cqe_get_data(cqe);
+		free(data);
+		writes--;
+		io_uring_cqe_seen(ring, cqe);
+	}
+
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	struct io_uring ring;
+	off_t insize;
+	int ret;
+
+	if (argc < 3) {
+		printf("%s: infile outfile\n", argv[0]);
+		return 1;
+	}
+
+	infd = open(argv[1], O_RDONLY);
+	if (infd < 0) {
+		perror("open infile");
+		return 1;
+	}
+	outfd = open(argv[2], O_WRONLY | O_CREAT | O_TRUNC, 0644);
+	if (outfd < 0) {
+		perror("open outfile");
+		return 1;
+	}
+
+	if (setup_context(QD, &ring))
+		return 1;
+	if (get_file_size(infd, &insize))
+		return 1;
+
+	ret = copy_file(&ring, insize);
+
+	close(infd);
+	close(outfd);
+	io_uring_queue_exit(&ring);
+	return ret;
+}
diff --git a/examples/io_uring-test.c b/examples/io_uring-test.c
new file mode 100644
index 0000000..1a68536
--- /dev/null
+++ b/examples/io_uring-test.c
@@ -0,0 +1,112 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Simple app that demonstrates how to setup an io_uring interface,
+ * submit and complete IO against it, and then tear it down.
+ *
+ * gcc -Wall -O2 -D_GNU_SOURCE -o io_uring-test io_uring-test.c -luring
+ */
+#include <stdio.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include "liburing.h"
+
+#define QD	4
+
+int main(int argc, char *argv[])
+{
+	struct io_uring ring;
+	int i, fd, ret, pending, done;
+	struct io_uring_sqe *sqe;
+	struct io_uring_cqe *cqe;
+	struct iovec *iovecs;
+	struct stat sb;
+	ssize_t fsize;
+	off_t offset;
+	void *buf;
+
+	if (argc < 2) {
+		printf("%s: file\n", argv[0]);
+		return 1;
+	}
+
+	ret = io_uring_queue_init(QD, &ring, 0);
+	if (ret < 0) {
+		fprintf(stderr, "queue_init: %s\n", strerror(-ret));
+		return 1;
+	}
+
+	fd = open(argv[1], O_RDONLY | O_DIRECT);
+	if (fd < 0) {
+		perror("open");
+		return 1;
+	}
+
+	if (fstat(fd, &sb) < 0) {
+		perror("fstat");
+		return 1;
+	}
+
+	fsize = 0;
+	iovecs = calloc(QD, sizeof(struct iovec));
+	for (i = 0; i < QD; i++) {
+		if (posix_memalign(&buf, 4096, 4096))
+			return 1;
+		iovecs[i].iov_base = buf;
+		iovecs[i].iov_len = 4096;
+		fsize += 4096;
+	}
+
+	offset = 0;
+	i = 0;
+	do {
+		sqe = io_uring_get_sqe(&ring);
+		if (!sqe)
+			break;
+		io_uring_prep_readv(sqe, fd, &iovecs[i], 1, offset);
+		offset += iovecs[i].iov_len;
+		i++;
+		if (offset > sb.st_size)
+			break;
+	} while (1);
+
+	ret = io_uring_submit(&ring);
+	if (ret < 0) {
+		fprintf(stderr, "io_uring_submit: %s\n", strerror(-ret));
+		return 1;
+	} else if (ret != i) {
+		fprintf(stderr, "io_uring_submit submitted less %d\n", ret);
+		return 1;
+	}
+
+	done = 0;
+	pending = ret;
+	fsize = 0;
+	for (i = 0; i < pending; i++) {
+		ret = io_uring_wait_cqe(&ring, &cqe);
+		if (ret < 0) {
+			fprintf(stderr, "io_uring_wait_cqe: %s\n", strerror(-ret));
+			return 1;
+		}
+
+		done++;
+		ret = 0;
+		if (cqe->res != 4096 && cqe->res + fsize != sb.st_size) {
+			fprintf(stderr, "ret=%d, wanted 4096\n", cqe->res);
+			ret = 1;
+		}
+		fsize += cqe->res;
+		io_uring_cqe_seen(&ring, cqe);
+		if (ret)
+			break;
+	}
+
+	printf("Submitted=%d, completed=%d, bytes=%lu\n", pending, done,
+						(unsigned long) fsize);
+	close(fd);
+	io_uring_queue_exit(&ring);
+	return 0;
+}
diff --git a/examples/link-cp.c b/examples/link-cp.c
new file mode 100644
index 0000000..e15dfc3
--- /dev/null
+++ b/examples/link-cp.c
@@ -0,0 +1,193 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Very basic proof-of-concept for doing a copy with linked SQEs. Needs a
+ * bit of error handling and short read love.
+ */
+#include <stdio.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <assert.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include "liburing.h"
+
+#define QD	64
+#define BS	(32*1024)
+
+struct io_data {
+	size_t offset;
+	int index;
+	struct iovec iov;
+};
+
+static int infd, outfd;
+static unsigned inflight;
+
+static int setup_context(unsigned entries, struct io_uring *ring)
+{
+	int ret;
+
+	ret = io_uring_queue_init(entries, ring, 0);
+	if (ret < 0) {
+		fprintf(stderr, "queue_init: %s\n", strerror(-ret));
+		return -1;
+	}
+
+	return 0;
+}
+
+static int get_file_size(int fd, off_t *size)
+{
+	struct stat st;
+
+	if (fstat(fd, &st) < 0)
+		return -1;
+	if (S_ISREG(st.st_mode)) {
+		*size = st.st_size;
+		return 0;
+	} else if (S_ISBLK(st.st_mode)) {
+		unsigned long long bytes;
+
+		if (ioctl(fd, BLKGETSIZE64, &bytes) != 0)
+			return -1;
+
+		*size = bytes;
+		return 0;
+	}
+
+	return -1;
+}
+
+static void queue_rw_pair(struct io_uring *ring, off_t size, off_t offset)
+{
+	struct io_uring_sqe *sqe;
+	struct io_data *data;
+	void *ptr;
+
+	ptr = malloc(size + sizeof(*data));
+	data = ptr + size;
+	data->index = 0;
+	data->offset = offset;
+	data->iov.iov_base = ptr;
+	data->iov.iov_len = size;
+
+	sqe = io_uring_get_sqe(ring);
+	io_uring_prep_readv(sqe, infd, &data->iov, 1, offset);
+	sqe->flags |= IOSQE_IO_LINK;
+	io_uring_sqe_set_data(sqe, data);
+
+	sqe = io_uring_get_sqe(ring);
+	io_uring_prep_writev(sqe, outfd, &data->iov, 1, offset);
+	io_uring_sqe_set_data(sqe, data);
+}
+
+static int handle_cqe(struct io_uring *ring, struct io_uring_cqe *cqe)
+{
+	struct io_data *data = io_uring_cqe_get_data(cqe);
+	int ret = 0;
+
+	data->index++;
+
+	if (cqe->res < 0) {
+		if (cqe->res == -ECANCELED) {
+			queue_rw_pair(ring, BS, data->offset);
+			inflight += 2;
+		} else {
+			printf("cqe error: %s\n", strerror(-cqe->res));
+			ret = 1;
+		}
+	}
+
+	if (data->index == 2) {
+		void *ptr = (void *) data - data->iov.iov_len;
+
+		free(ptr);
+	}
+	io_uring_cqe_seen(ring, cqe);
+	return ret;
+}
+
+static int copy_file(struct io_uring *ring, off_t insize)
+{
+	struct io_uring_cqe *cqe;
+	size_t this_size;
+	off_t offset;
+
+	offset = 0;
+	while (insize) {
+		int has_inflight = inflight;
+		int depth;
+
+		while (insize && inflight < QD) {
+			this_size = BS;
+			if (this_size > insize)
+				this_size = insize;
+			queue_rw_pair(ring, this_size, offset);
+			offset += this_size;
+			insize -= this_size;
+			inflight += 2;
+		}
+
+		if (has_inflight != inflight)
+			io_uring_submit(ring);
+
+		if (insize)
+			depth = QD;
+		else
+			depth = 1;
+		while (inflight >= depth) {
+			int ret;
+
+			ret = io_uring_wait_cqe(ring, &cqe);
+			if (ret < 0) {
+				printf("wait cqe: %s\n", strerror(-ret));
+				return 1;
+			}
+			if (handle_cqe(ring, cqe))
+				return 1;
+			inflight--;
+		}
+	}
+
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	struct io_uring ring;
+	off_t insize;
+	int ret;
+
+	if (argc < 3) {
+		printf("%s: infile outfile\n", argv[0]);
+		return 1;
+	}
+
+	infd = open(argv[1], O_RDONLY);
+	if (infd < 0) {
+		perror("open infile");
+		return 1;
+	}
+	outfd = open(argv[2], O_WRONLY | O_CREAT | O_TRUNC, 0644);
+	if (outfd < 0) {
+		perror("open outfile");
+		return 1;
+	}
+
+	if (setup_context(QD, &ring))
+		return 1;
+	if (get_file_size(infd, &insize))
+		return 1;
+
+	ret = copy_file(&ring, insize);
+
+	close(infd);
+	close(outfd);
+	io_uring_queue_exit(&ring);
+	return ret;
+}
diff --git a/examples/ucontext-cp.c b/examples/ucontext-cp.c
new file mode 100644
index 0000000..ea0c934
--- /dev/null
+++ b/examples/ucontext-cp.c
@@ -0,0 +1,273 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * gcc -Wall -O2 -D_GNU_SOURCE -o ucontext-cp ucontext-cp.c -luring
+ */
+#define _POSIX_C_SOURCE 199309L
+#include <stdio.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <assert.h>
+#include <errno.h>
+#include <ucontext.h>
+#include <signal.h>
+#include <inttypes.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <sys/timerfd.h>
+#include <sys/poll.h>
+#include "liburing.h"
+
+#define QD	64
+#define BS	1024
+
+#ifndef SIGSTKSZ
+#define SIGSTKSZ 8192
+#endif
+
+typedef struct {
+	struct io_uring *ring;
+	unsigned char *stack_buf;
+	ucontext_t ctx_main, ctx_fnew;
+} async_context;
+
+typedef struct {
+	async_context *pctx;
+	int *psuccess;
+	int *pfailure;
+	int infd;
+	int outfd;
+} arguments_bundle;
+
+#define DEFINE_AWAIT_OP(operation) 					\
+static ssize_t await_##operation(					\
+	async_context *pctx,						\
+	int fd,								\
+	const struct iovec *ioves,					\
+	unsigned int nr_vecs,						\
+	off_t offset)							\
+{									\
+	struct io_uring_sqe *sqe = io_uring_get_sqe(pctx->ring);	\
+	struct io_uring_cqe *cqe;					\
+									\
+	if (!sqe)							\
+		return -1;						\
+									\
+	io_uring_prep_##operation(sqe, fd, ioves, nr_vecs, offset);	\
+	io_uring_sqe_set_data(sqe, pctx);				\
+	swapcontext(&pctx->ctx_fnew, &pctx->ctx_main);			\
+	io_uring_peek_cqe(pctx->ring, &cqe);				\
+	assert(cqe);							\
+	io_uring_cqe_seen(pctx->ring, cqe);				\
+									\
+	return cqe->res;						\
+}
+
+DEFINE_AWAIT_OP(readv)
+DEFINE_AWAIT_OP(writev)
+#undef DEFINE_AWAIT_OP
+
+int await_poll(async_context *pctx, int fd, short poll_mask) {
+	struct io_uring_sqe *sqe = io_uring_get_sqe(pctx->ring);
+	struct io_uring_cqe *cqe;
+	if (!sqe)
+		return -1;
+
+	io_uring_prep_poll_add(sqe, fd, poll_mask);
+	io_uring_sqe_set_data(sqe, pctx);
+	swapcontext(&pctx->ctx_fnew, &pctx->ctx_main);
+	io_uring_peek_cqe(pctx->ring, &cqe);
+	assert(cqe);
+	io_uring_cqe_seen(pctx->ring, cqe);
+
+	return cqe->res;
+}
+
+int await_delay(async_context *pctx, time_t seconds) {
+	struct io_uring_sqe *sqe = io_uring_get_sqe(pctx->ring);
+	struct io_uring_cqe *cqe;
+	struct __kernel_timespec ts = {
+		.tv_sec = seconds,
+		.tv_nsec = 0
+	};
+
+	if (!sqe)
+		return -1;
+
+	io_uring_prep_timeout(sqe, &ts, 0, 0);
+	io_uring_sqe_set_data(sqe, pctx);
+	swapcontext(&pctx->ctx_fnew, &pctx->ctx_main);
+	io_uring_peek_cqe(pctx->ring, &cqe);
+	assert(cqe);
+	io_uring_cqe_seen(pctx->ring, cqe);
+
+	return 0;
+}
+
+static int setup_context(async_context *pctx, struct io_uring *ring)
+{
+	int ret;
+
+	pctx->ring = ring;
+	ret = getcontext(&pctx->ctx_fnew);
+	if (ret < 0) {
+		perror("getcontext");
+		return -1;
+	}
+	pctx->stack_buf = malloc(SIGSTKSZ);
+	if (!pctx->stack_buf) {
+		perror("malloc");
+		return -1;
+	}
+	pctx->ctx_fnew.uc_stack.ss_sp = pctx->stack_buf;
+	pctx->ctx_fnew.uc_stack.ss_size = SIGSTKSZ;
+	pctx->ctx_fnew.uc_link = &pctx->ctx_main;
+
+	return 0;
+}
+
+static int copy_file(async_context *pctx, int infd, int outfd, struct iovec* piov)
+{
+	off_t offset = 0;
+
+	for (;;) {
+		ssize_t bytes_read;
+
+		printf("%d->%d: readv %ld bytes from %ld\n", infd, outfd, (long) piov->iov_len, (long) offset);
+		if ((bytes_read = await_readv(pctx, infd, piov, 1, offset)) < 0) {
+			perror("await_readv");
+			return 1;
+		}
+		if (bytes_read == 0)
+			return 0;
+
+		piov->iov_len = bytes_read;
+
+		printf("%d->%d: writev %ld bytes from %ld\n", infd, outfd, (long) piov->iov_len, (long) offset);
+		if (await_writev(pctx, outfd, piov, 1, offset) != bytes_read) {
+			perror("await_writev");
+			return 1;
+		}
+		if (bytes_read < BS)
+			return 0;
+		offset += bytes_read;
+
+		printf("%d->%d: wait %ds\n", infd, outfd, 1);
+		await_delay(pctx, 1);
+	}
+}
+
+static void copy_file_wrapper(arguments_bundle *pbundle)
+{
+	struct iovec iov = {
+		.iov_base = malloc(BS),
+		.iov_len = BS,
+	};
+	async_context *pctx = pbundle->pctx;
+
+	int ret = copy_file(pctx, pbundle->infd, pbundle->outfd, &iov);
+
+	printf("%d->%d: done with ret code %d\n", pbundle->infd, pbundle->outfd, ret);
+
+	if (ret == 0) {
+		++*pbundle->psuccess;
+	} else {
+		++*pbundle->pfailure;
+	}
+
+	free(iov.iov_base);
+	close(pbundle->infd);
+	close(pbundle->outfd);
+	free(pbundle->pctx->stack_buf);
+	free(pbundle->pctx);
+	free(pbundle);
+
+	swapcontext(&pctx->ctx_fnew, &pctx->ctx_main);
+}
+
+int main(int argc, char *argv[])
+{
+	struct io_uring ring;
+	int i, req_count, ret;
+	int success = 0, failure = 0;
+
+	if (argc < 3) {
+		fprintf(stderr, "%s: infile1 outfile1 [infile2 outfile2 [...]]\n", argv[0]);
+		return 1;
+	}
+
+	ret = io_uring_queue_init(QD, &ring, 0);
+	if (ret < 0) {
+		fprintf(stderr, "queue_init: %s\n", strerror(-ret));
+		return -1;
+	}
+
+	req_count = (argc - 1) / 2;
+	printf("copying %d files...\n", req_count);
+
+	for (i = 1; i < argc; i += 2) {
+		int infd, outfd;
+
+		async_context *pctx = malloc(sizeof(*pctx));
+
+		if (!pctx || setup_context(pctx, &ring))
+			return 1;
+
+		infd = open(argv[i], O_RDONLY);
+		if (infd < 0) {
+			perror("open infile");
+			return 1;
+		}
+		outfd = open(argv[i + 1], O_WRONLY | O_CREAT | O_TRUNC, 0644);
+		if (outfd < 0) {
+			perror("open outfile");
+			return 1;
+		}
+
+		arguments_bundle *pbundle = malloc(sizeof(*pbundle));
+		pbundle->pctx = pctx;
+		pbundle->psuccess = &success;
+		pbundle->pfailure = &failure;
+		pbundle->infd = infd;
+		pbundle->outfd = outfd;
+
+		makecontext(&pctx->ctx_fnew, (void (*)(void)) copy_file_wrapper, 1, pbundle);
+
+		if (swapcontext(&pctx->ctx_main, &pctx->ctx_fnew)) {
+			perror("swapcontext");
+			return 1;
+		}
+	}
+
+	/* event loop */
+	while (success + failure < req_count) {
+		struct io_uring_cqe *cqe;
+
+		/* usually be timed waiting */
+		ret = io_uring_submit_and_wait(&ring, 1);
+		if (ret < 0) {
+			fprintf(stderr, "submit_and_wait: %s\n", strerror(-ret));
+			return 1;
+		}
+
+		ret = io_uring_wait_cqe(&ring, &cqe);
+		if (ret < 0) {
+			fprintf(stderr, "wait_cqe: %s\n", strerror(-ret));
+			return 1;
+		}
+
+		async_context *pctx = io_uring_cqe_get_data(cqe);
+
+		if (swapcontext(&pctx->ctx_main, &pctx->ctx_fnew)) {
+			perror("swapcontext");
+			return 1;
+		}
+	}
+
+	io_uring_queue_exit(&ring);
+
+	printf("finished with %d success(es) and %d failure(s)\n", success, failure);
+
+	return failure > 0;
+}
diff --git a/liburing.pc.in b/liburing.pc.in
new file mode 100644
index 0000000..e621939
--- /dev/null
+++ b/liburing.pc.in
@@ -0,0 +1,12 @@
+prefix=@prefix@
+exec_prefix=${prefix}
+libdir=@libdir@
+includedir=@includedir@
+
+Name: @NAME@
+Version: @VERSION@
+Description: io_uring library
+URL: http://git.kernel.dk/cgit/liburing/
+
+Libs: -L${libdir} -luring
+Cflags: -I${includedir}
diff --git a/liburing.spec b/liburing.spec
new file mode 100644
index 0000000..0268d23
--- /dev/null
+++ b/liburing.spec
@@ -0,0 +1,66 @@
+Name: liburing
+Version: 2.0
+Release: 1%{?dist}
+Summary: Linux-native io_uring I/O access library
+License: (GPLv2 with exceptions and LGPLv2+) or MIT
+Source0: https://brick.kernel.dk/snaps/%{name}-%{version}.tar.gz
+Source1: https://brick.kernel.dk/snaps/%{name}-%{version}.tar.gz.asc
+URL: https://git.kernel.dk/cgit/liburing/
+BuildRequires: gcc
+BuildRequires: make
+
+%description
+Provides native async IO for the Linux kernel, in a fast and efficient
+manner, for both buffered and O_DIRECT.
+
+%package devel
+Summary: Development files for Linux-native io_uring I/O access library
+Requires: %{name}%{_isa} = %{version}-%{release}
+Requires: pkgconfig
+
+%description devel
+This package provides header files to include and libraries to link with
+for the Linux-native io_uring.
+
+%prep
+%autosetup
+
+%build
+%set_build_flags
+./configure --prefix=%{_prefix} --libdir=/%{_libdir} --libdevdir=/%{_libdir} --mandir=%{_mandir} --includedir=%{_includedir}
+
+%make_build
+
+%install
+%make_install
+
+%files
+%attr(0755,root,root) %{_libdir}/liburing.so.*
+%license COPYING
+
+%files devel
+%{_includedir}/liburing/
+%{_includedir}/liburing.h
+%{_libdir}/liburing.so
+%exclude %{_libdir}/liburing.a
+%{_libdir}/pkgconfig/*
+%{_mandir}/man2/*
+%{_mandir}/man3/*
+%{_mandir}/man7/*
+
+%changelog
+* Thu Oct 31 2019 Jeff Moyer <jmoyer@redhat.com> - 0.2-1
+- Add io_uring_cq_ready()
+- Add io_uring_peek_batch_cqe()
+- Add io_uring_prep_accept()
+- Add io_uring_prep_{recv,send}msg()
+- Add io_uring_prep_timeout_remove()
+- Add io_uring_queue_init_params()
+- Add io_uring_register_files_update()
+- Add io_uring_sq_space_left()
+- Add io_uring_wait_cqe_timeout()
+- Add io_uring_wait_cqes()
+- Add io_uring_wait_cqes_timeout()
+
+* Tue Jan 8 2019 Jens Axboe <axboe@kernel.dk> - 0.1
+- Initial version
diff --git a/make-debs.sh b/make-debs.sh
new file mode 100755
index 0000000..01d563c
--- /dev/null
+++ b/make-debs.sh
@@ -0,0 +1,53 @@
+#!/usr/bin/env bash
+# Copyright (C) 2019  Liu Changcheng <changcheng.liu@aliyun.com>
+# Author: Liu Changcheng <changcheng.liu@aliyun.com>
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+set -xe
+
+# Create dir for build
+base=${1:-/tmp/release}
+codename=$(lsb_release -sc)
+releasedir=$base/$(lsb_release -si)/liburing
+rm -rf $releasedir
+mkdir -p $releasedir
+
+src_dir=$(readlink -e `basename $0`)
+liburing_dir=$(dirname $src_dir)
+basename=$(basename $liburing_dir)
+dirname=$(dirname $liburing_dir)
+version=$(git describe --match "lib*" | cut -d '-' -f 2)
+outfile="liburing-$version"
+orgfile=$(echo $outfile | tr '-' '_')
+
+# Prepare source code
+cp -arf ${dirname}/${basename} ${releasedir}/${outfile}
+cd ${releasedir}/${outfile}
+git clean -dxf
+
+# Change changelog if it's needed
+cur_ver=`head -l debian/changelog | sed -n -e 's/.* (\(.*\)) .*/\1/p'`
+if [ "$cur_ver" != "$version-1" ]; then
+	dch -D $codename --force-distribution -b -v "$version-1" "new version"
+fi
+
+# Create tar archieve
+cd ../
+tar cvzf ${outfile}.tar.gz ${outfile}
+ln -s ${outfile}.tar.gz ${orgfile}.orig.tar.gz
+
+# Build debian package
+cd -
+debuild
diff --git a/man/io_uring.7 b/man/io_uring.7
new file mode 100644
index 0000000..a63b3e9
--- /dev/null
+++ b/man/io_uring.7
@@ -0,0 +1,736 @@
+.\" Copyright (C) 2020 Shuveb Hussain <shuveb@gmail.com>
+.\" SPDX-License-Identifier: LGPL-2.0-or-later
+.\"
+
+.TH IO_URING 7 2020-07-26 "Linux" "Linux Programmer's Manual"
+.SH NAME
+io_uring \- Asynchronous I/O facility
+.SH SYNOPSIS
+.nf
+.B "#include <linux/io_uring.h>"
+.fi
+.PP
+.SH DESCRIPTION
+.PP
+.B io_uring
+is a Linux-specific API for asynchronous I/O.
+It allows the user to submit one or more I/O requests,
+which are processed asynchronously without blocking the calling process.
+.B io_uring
+gets its name from ring buffers which are shared between user space and
+kernel space. This arrangement allows for efficient I/O,
+while avoiding the overhead of copying buffers between them,
+where possible.
+This interface makes
+.B io_uring
+different from other UNIX I/O APIs,
+wherein,
+rather than just communicate between kernel and user space with system calls, 
+ring buffers are used as the main mode of communication.
+This arrangement has various performance benefits which are discussed in a
+separate section below.
+This man page uses the terms shared buffers, shared ring buffers and
+queues interchangeably.
+.PP
+The general programming model you need to follow for
+.B io_uring
+is outlined below
+.IP \(bu
+Set up shared buffers with
+.BR io_uring_setup (2)
+and
+.BR mmap (2),
+mapping into user space shared buffers for the submission queue (SQ) and the 
+completion queue (CQ).
+You place I/O requests you want to make on the SQ,
+while the kernel places the results of those operations on the CQ.
+.IP \(bu
+For every I/O request you need to make (like to read a file, write a file, 
+accept a socket connection, etc), you create a submission queue entry,
+or SQE,
+describe the I/O operation you need to get done and add it to the tail of
+the submission queue (SQ).
+Each I/O operation is,
+in essence,
+the equivalent of a system call you would have made otherwise,
+if you were not using
+.BR io_uring .
+You can add more than one SQE to the queue depending on the number of
+operations you want to request.
+.IP \(bu
+After you add one or more SQEs,
+you need to call
+.BR io_uring_enter (2)
+to tell the kernel to dequeue your I/O requests off the SQ and begin
+processing them.
+.IP \(bu
+For each SQE you submit,
+once it is done processing the request,
+the kernel places a completion queue event or CQE at the tail of the
+completion queue or CQ.
+The kernel places exactly one matching CQE in the CQ for every SQE you
+submit on the SQ.
+After you retrieve a CQE,
+minimally,
+you might be interested in checking the
+.I res
+field of the CQE structure,
+which corresponds to the return value of the system
+call's equivalent,
+had you used it directly without using 
+.BR io_uring .
+For instance,
+a read operation under 
+.BR io_uring ,
+started with the
+.BR IORING_OP_READ
+operation,
+which issues the equivalent of the
+.BR read (2) 
+system call,
+would return as part of 
+.I res
+what
+.BR read (2)
+would have returned if called directly,
+without using 
+.BR io_uring .
+.IP \(bu
+Optionally, 
+.BR io_uring_enter (2)
+can also wait for a specified number of requests to be processed by the kernel
+before it returns.
+If you specified a certain number of completions to wait for,
+the kernel would have placed at least those many number of CQEs on the CQ,
+which you can then readily read,
+right after the return from
+.BR io_uring_enter (2).
+.IP \(bu
+It is important to remember that I/O requests submitted to the kernel can
+complete in any order.
+It is not necessary for the kernel to process one request after another,
+in the order you placed them.
+Given that the interface is a ring,
+the requests are attempted in order,
+however that doesn't imply any sort of ordering on their completion.
+When more than one request is in flight,
+it is not possible to determine which one will complete first.
+When you dequeue CQEs off the CQ,
+you should always check which submitted request it corresponds to.
+The most common method for doing so is utilizing the
+.I user_data
+field in the request, which is passed back on the completion side.
+.PP
+Adding to and reading from the queues:
+.IP \(bu
+You add SQEs to the tail of the SQ.
+The kernel reads SQEs off the head of the queue.
+.IP \(bu
+The kernel adds CQEs to the tail of the CQ.
+You read CQEs off the head of the queue.
+.SS Submission queue polling
+One of the goals of 
+.B io_uring
+is to provide a means for efficient I/O.
+To this end,
+.B io_uring
+supports a polling mode that lets you avoid the call to
+.BR io_uring_enter (2),
+which you use to inform the kernel that you have queued SQEs on to the SQ.
+With SQ Polling,
+.B io_uring
+starts a kernel thread that polls the submission queue for any I/O
+requests you submit by adding SQEs.
+With SQ Polling enabled,
+there is no need for you to call 
+.BR io_uring_enter (2),
+letting you avoid the overhead of system calls.
+A designated kernel thread dequeues SQEs off the SQ as you add them and
+dispatches them for asynchronous processing.
+.SS Setting up io_uring
+.PP
+The main steps in setting up
+.B io_uring
+consist of mapping in the shared buffers with
+.BR mmap (2)
+calls.
+In the example program included in this man page, 
+the function
+.BR app_setup_uring ()
+sets up 
+.B io_uring
+with a QUEUE_DEPTH deep submission queue.
+Pay attention to the 2 
+.BR mmap (2)
+calls that set up the shared submission and completion queues.
+If your kernel is older than version 5.4,
+three 
+.BR mmap(2) 
+calls are required.
+.PP
+.SS Submitting I/O requests
+The process of submitting a request consists of describing the I/O
+operation you need to get done using an 
+.B io_uring_sqe
+structure instance.
+These details describe the equivalent system call and its parameters.
+Because the range of I/O operations Linux supports are very varied and the
+.B io_uring_sqe
+structure needs to be able to describe them, 
+it has several fields,
+some packed into unions for space efficiency.
+Here is a simplified version of struct 
+.B io_uring_sqe 
+with some of the most often used fields:
+.PP
+.in +4n
+.EX
+struct io_uring_sqe {
+        __u8    opcode;         /* type of operation for this sqe */
+        __s32   fd;             /* file descriptor to do IO on */
+        __u64   off;            /* offset into file */
+        __u64   addr;           /* pointer to buffer or iovecs */
+        __u32   len;            /* buffer size or number of iovecs */
+        __u64   user_data;      /* data to be passed back at completion time */
+        __u8    flags;          /* IOSQE_ flags */
+        ...
+};
+.EE
+.in
+
+Here is struct 
+.B io_uring_sqe
+in full:
+
+.in +4n
+.EX
+struct io_uring_sqe {
+        __u8    opcode;         /* type of operation for this sqe */
+        __u8    flags;          /* IOSQE_ flags */
+        __u16   ioprio;         /* ioprio for the request */
+        __s32   fd;             /* file descriptor to do IO on */
+        union {
+                __u64   off;    /* offset into file */
+                __u64   addr2;
+        };
+        union {
+                __u64   addr;   /* pointer to buffer or iovecs */
+                __u64   splice_off_in;
+        };
+        __u32   len;            /* buffer size or number of iovecs */
+        union {
+                __kernel_rwf_t  rw_flags;
+                __u32           fsync_flags;
+                __u16           poll_events;    /* compatibility */
+                __u32           poll32_events;  /* word-reversed for BE */
+                __u32           sync_range_flags;
+                __u32           msg_flags;
+                __u32           timeout_flags;
+                __u32           accept_flags;
+                __u32           cancel_flags;
+                __u32           open_flags;
+                __u32           statx_flags;
+                __u32           fadvise_advice;
+                __u32           splice_flags;
+        };
+        __u64   user_data;      /* data to be passed back at completion time */
+        union {
+                struct {
+                        /* pack this to avoid bogus arm OABI complaints */
+                        union {
+                                /* index into fixed buffers, if used */
+                                __u16   buf_index;
+                                /* for grouped buffer selection */
+                                __u16   buf_group;
+                        } __attribute__((packed));
+                        /* personality to use, if used */
+                        __u16   personality;
+                        __s32   splice_fd_in;
+                };
+                __u64   __pad2[3];
+        };
+};
+.EE
+.in
+.PP
+To submit an I/O request to 
+.BR io_uring ,
+you need to acquire a submission queue entry (SQE) from the submission
+queue (SQ),
+fill it up with details of the operation you want to submit and call 
+.BR io_uring_enter (2). 
+If you want to avoid calling 
+.BR io_uring_enter (2),
+you have the option of setting up Submission Queue Polling.
+.PP
+SQEs are added to the tail of the submission queue.
+The kernel picks up SQEs off the head of the SQ.
+The general algorithm to get the next available SQE and update the tail is
+as follows.
+.PP
+.in +4n
+.EX
+struct io_uring_sqe *sqe;
+unsigned tail, index;
+tail = *sqring->tail;
+index = tail & (*sqring->ring_mask);
+sqe = &sqring->sqes[index];
+/* fill up details about this I/O request */
+describe_io(sqe);
+/* fill the sqe index into the SQ ring array */
+sqring->array[index] = index;
+tail++;
+atomic_store_release(sqring->tail, tail);
+.EE
+.in
+.PP
+To get the index of an entry,
+the application must mask the current tail index with the size mask of the
+ring.
+This holds true for both SQs and CQs.
+Once the SQE is acquired,
+the necessary fields are filled in,
+describing the request.
+While the CQ ring directly indexes the shared array of CQEs,
+the submission side has an indirection array between them.
+The submission side ring buffer is an index into this array,
+which in turn contains the index into the SQEs.
+.PP
+The following code snippet demonstrates how a read operation,
+an equivalent of a
+.BR preadv2 (2)
+system call is described by filling up an SQE with the necessary
+parameters.
+.PP
+.in +4n
+.EX
+struct iovec iovecs[16];
+ ...
+sqe->opcode = IORING_OP_READV;
+sqe->fd = fd;
+sqe->addr = (unsigned long) iovecs;
+sqe->len = 16;
+sqe->off = offset;
+sqe->flags = 0;
+.EE
+.in
+.TP 
+.B Memory ordering
+Modern compilers and CPUs freely reorder reads and writes without 
+affecting the program's outcome to optimize performance. 
+Some aspects of this need to be kept in mind on SMP systems since 
+.B io_uring
+involves buffers shared between kernel and user space.
+These buffers are both visible and modifiable from kernel and user space.
+As heads and tails belonging to these shared buffers are updated by kernel
+and user space,
+changes need to be coherently visible on either side,
+irrespective of whether a CPU switch took place after the kernel-user mode
+switch happened.
+We use memory barriers to enforce this coherency.
+Being significantly large subjects on their own,
+memory barriers are out of scope for further discussion on this man page.
+.TP
+.B Letting the kernel know about I/O submissions
+Once you place one or more SQEs on to the SQ,
+you need to let the kernel know that you've done so.
+You can do this by calling the
+.BR io_uring_enter (2) 
+system call.
+This system call is also capable of waiting for a specified count of
+events to complete.
+This way,
+you can be sure to find completion events in the completion queue without
+having to poll it for events later.
+.SS Reading completion events
+Similar to the submission queue (SQ),
+the completion queue (CQ) is a shared buffer between the kernel and user
+space.
+Whereas you placed submission queue entries on the tail of the SQ and the
+kernel read off the head,
+when it comes to the CQ,
+the kernel places completion queue events or CQEs on the tail of the CQ and
+you read off its head.
+.PP
+Submission is flexible (and thus a bit more complicated) since it needs to
+be able to encode different types of system calls that take various
+parameters.
+Completion,
+on the other hand is simpler since we're looking only for a return value
+back from the kernel.
+This is easily understood by looking at the completion queue event
+structure,
+struct 
+.BR io_uring_cqe :
+.PP
+.in +4n
+.EX
+struct io_uring_cqe {
+	__u64	user_data;  /* sqe->data submission passed back */
+	__s32	res;        /* result code for this event */
+	__u32	flags;
+};
+.EE
+.in
+.PP
+Here,
+.I user_data
+is custom data that is passed unchanged from submission to completion.
+That is,
+from SQEs to CQEs.
+This field can be used to set context,
+uniquely identifying submissions that got completed.
+Given that I/O requests can complete in any order,
+this field can be used to correlate a submission with a completion.
+.I res
+is the result from the system call that was performed as part of the
+submission;
+its return value.
+The
+.I flags
+field could carry request-specific metadata in the future,
+but is currently unused.
+.PP
+The general sequence to read completion events off the completion queue is
+as follows:
+.PP
+.in +4n
+.EX
+unsigned head;
+head = *cqring->head;
+if (head != atomic_load_acquire(cqring->tail)) {
+    struct io_uring_cqe *cqe;
+    unsigned index;
+    index = head & (cqring->mask);
+    cqe = &cqring->cqes[index];
+    /* process completed CQE */
+    process_cqe(cqe);
+    /* CQE consumption complete */
+    head++;
+}
+atomic_store_release(cqring->head, head);
+.EE
+.in
+.PP
+It helps to be reminded that the kernel adds CQEs to the tail of the CQ,
+while you need to dequeue them off the head.
+To get the index of an entry at the head,
+the application must mask the current head index with the size mask of the
+ring.
+Once the CQE has been consumed or processed,
+the head needs to be updated to reflect the consumption of the CQE.
+Attention should be paid to the read and write barriers to ensure
+successful read and update of the head.
+.SS io_uring performance
+Because of the shared ring buffers between kernel and user space,
+.B io_uring
+can be a zero-copy system.
+Copying buffers to and fro becomes necessary when system calls that
+transfer data between kernel and user space are involved.
+But since the bulk of the communication in 
+.B io_uring
+is via buffers shared between the kernel and user space,
+this huge performance overhead is completely avoided.
+.PP
+While system calls may not seem like a significant overhead,
+in high performance applications,
+making a lot of them will begin to matter.
+While workarounds the operating system has in place to deal with Specter
+and Meltdown are ideally best done away with,
+unfortunately,
+some of these workarounds are around the system call interface,
+making system calls not as cheap as before on affected hardware.
+While newer hardware should not need these workarounds,
+hardware with these vulnerabilities can be expected to be in the wild for a
+long time.
+While using synchronous programming interfaces or even when using
+asynchronous programming interfaces under Linux,
+there is at least one system call involved in the submission of each
+request.
+In
+.BR io_uring ,
+on the other hand,
+you can batch several requests in one go,
+simply by queueing up multiple SQEs,
+each describing an I/O operation you want and make a single call to 
+.BR io_uring_enter (2). 
+This is possible due to
+.BR io_uring 's
+shared buffers based design.
+.PP
+While this batching in itself can avoid the overhead associated with
+potentially multiple and frequent system calls,
+you can reduce even this overhead further with Submission Queue Polling,
+by having the kernel poll and pick up your SQEs for processing as you add
+them to the submission queue. This avoids the
+.BR io_uring_enter (2)
+call you need to make to tell the kernel to pick SQEs up.
+For high-performance applications,
+this means even lesser system call overheads.
+.SH CONFORMING TO
+.B io_uring
+is Linux-specific.
+.SH EXAMPLES
+The following example uses
+.B io_uring
+to copy stdin to stdout.
+Using shell redirection,
+you should be able to copy files with this example.
+Because it uses a queue depth of only one,
+this example processes I/O requests one after the other.
+It is purposefully kept this way to aid understanding.
+In real-world scenarios however,
+you'll want to have a larger queue depth to parallelize I/O request
+processing so as to gain the kind of performance benefits
+.B io_uring
+provides with its asynchronous processing of requests.
+.PP
+.EX
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/syscall.h>
+#include <sys/mman.h>
+#include <sys/uio.h>
+#include <linux/fs.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdatomic.h>
+
+#include <linux/io_uring.h>
+
+#define QUEUE_DEPTH 1
+#define BLOCK_SZ    1024
+
+/* Macros for barriers needed by io_uring */
+#define io_uring_smp_store_release(p, v)            \\
+    atomic_store_explicit((_Atomic typeof(*(p)) *)(p), (v), \\
+                  memory_order_release)
+#define io_uring_smp_load_acquire(p)                \\
+    atomic_load_explicit((_Atomic typeof(*(p)) *)(p),   \\
+                 memory_order_acquire)
+
+int ring_fd;
+unsigned *sring_tail, *sring_mask, *sring_array, 
+            *cring_head, *cring_tail, *cring_mask;
+struct io_uring_sqe *sqes;
+struct io_uring_cqe *cqes;
+char buff[BLOCK_SZ];
+off_t offset;
+
+/*
+ * System call wrappers provided since glibc does not yet
+ * provide wrappers for io_uring system calls.
+* */
+
+int io_uring_setup(unsigned entries, struct io_uring_params *p)
+{
+    return (int) syscall(__NR_io_uring_setup, entries, p);
+}
+
+int io_uring_enter(int ring_fd, unsigned int to_submit,
+                   unsigned int min_complete, unsigned int flags)
+{
+    return (int) syscall(__NR_io_uring_enter, ring_fd, to_submit, min_complete,
+                         flags, NULL, 0);
+}
+
+int app_setup_uring(void) {
+    struct io_uring_params p;
+    void *sq_ptr, *cq_ptr;
+
+    /* See io_uring_setup(2) for io_uring_params.flags you can set */
+    memset(&p, 0, sizeof(p));
+    ring_fd = io_uring_setup(QUEUE_DEPTH, &p);
+    if (ring_fd < 0) {
+        perror("io_uring_setup");
+        return 1;
+    }
+
+    /*
+     * io_uring communication happens via 2 shared kernel-user space ring
+     * buffers, which can be jointly mapped with a single mmap() call in
+     * kernels >= 5.4.
+     */
+
+    int sring_sz = p.sq_off.array + p.sq_entries * sizeof(unsigned);
+    int cring_sz = p.cq_off.cqes + p.cq_entries * sizeof(struct io_uring_cqe);
+
+    /* Rather than check for kernel version, the recommended way is to
+     * check the features field of the io_uring_params structure, which is a 
+     * bitmask. If IORING_FEAT_SINGLE_MMAP is set, we can do away with the
+     * second mmap() call to map in the completion ring separately.
+     */
+    if (p.features & IORING_FEAT_SINGLE_MMAP) {
+        if (cring_sz > sring_sz)
+            sring_sz = cring_sz;
+        cring_sz = sring_sz;
+    }
+
+    /* Map in the submission and completion queue ring buffers.
+     *  Kernels < 5.4 only map in the submission queue, though.
+     */
+    sq_ptr = mmap(0, sring_sz, PROT_READ | PROT_WRITE,
+                  MAP_SHARED | MAP_POPULATE,
+                  ring_fd, IORING_OFF_SQ_RING);
+    if (sq_ptr == MAP_FAILED) {
+        perror("mmap");
+        return 1;
+    }
+
+    if (p.features & IORING_FEAT_SINGLE_MMAP) {
+        cq_ptr = sq_ptr;
+    } else {
+        /* Map in the completion queue ring buffer in older kernels separately */
+        cq_ptr = mmap(0, cring_sz, PROT_READ | PROT_WRITE,
+                      MAP_SHARED | MAP_POPULATE,
+                      ring_fd, IORING_OFF_CQ_RING);
+        if (cq_ptr == MAP_FAILED) {
+            perror("mmap");
+            return 1;
+        }
+    }
+    /* Save useful fields for later easy reference */
+    sring_tail = sq_ptr + p.sq_off.tail;
+    sring_mask = sq_ptr + p.sq_off.ring_mask;
+    sring_array = sq_ptr + p.sq_off.array;
+
+    /* Map in the submission queue entries array */
+    sqes = mmap(0, p.sq_entries * sizeof(struct io_uring_sqe),
+                   PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE,
+                   ring_fd, IORING_OFF_SQES);
+    if (sqes == MAP_FAILED) {
+        perror("mmap");
+        return 1;
+    }
+
+    /* Save useful fields for later easy reference */
+    cring_head = cq_ptr + p.cq_off.head;
+    cring_tail = cq_ptr + p.cq_off.tail;
+    cring_mask = cq_ptr + p.cq_off.ring_mask;
+    cqes = cq_ptr + p.cq_off.cqes;
+
+    return 0;
+}
+
+/*
+* Read from completion queue.
+* In this function, we read completion events from the completion queue.
+* We dequeue the CQE, update and head and return the result of the operation.
+* */
+
+int read_from_cq() {
+    struct io_uring_cqe *cqe;
+    unsigned head, reaped = 0;
+
+    /* Read barrier */
+    head = io_uring_smp_load_acquire(cring_head);
+    /*
+    * Remember, this is a ring buffer. If head == tail, it means that the
+    * buffer is empty.
+    * */
+    if (head == *cring_tail)
+        return -1;
+
+    /* Get the entry */
+    cqe = &cqes[head & (*cring_mask)];
+    if (cqe->res < 0)
+        fprintf(stderr, "Error: %s\\n", strerror(abs(cqe->res)));
+
+    head++;
+
+    /* Write barrier so that update to the head are made visible */
+    io_uring_smp_store_release(cring_head, head);
+
+    return cqe->res;
+}
+
+/*
+* Submit a read or a write request to the submission queue.
+* */
+
+int submit_to_sq(int fd, int op) {
+    unsigned index, tail;
+
+    /* Add our submission queue entry to the tail of the SQE ring buffer */
+    tail = *sring_tail;
+    index = tail & *sring_mask;
+    struct io_uring_sqe *sqe = &sqes[index];
+    /* Fill in the parameters required for the read or write operation */
+    sqe->opcode = op;
+    sqe->fd = fd;
+    sqe->addr = (unsigned long) buff;
+    if (op == IORING_OP_READ) {
+        memset(buff, 0, sizeof(buff));
+        sqe->len = BLOCK_SZ;
+    }
+    else {
+        sqe->len = strlen(buff);
+    }
+    sqe->off = offset;
+
+    sring_array[index] = index;
+    tail++;
+
+    /* Update the tail */
+    io_uring_smp_store_release(sring_tail, tail);
+
+    /*
+    * Tell the kernel we have submitted events with the io_uring_enter() system
+    * call. We also pass in the IOURING_ENTER_GETEVENTS flag which causes the
+    * io_uring_enter() call to wait until min_complete (the 3rd param) events
+    * complete.
+    * */
+    int ret =  io_uring_enter(ring_fd, 1,1,
+                              IORING_ENTER_GETEVENTS);
+    if(ret < 0) {
+        perror("io_uring_enter");
+        return -1;
+    }
+
+    return ret;
+}
+
+int main(int argc, char *argv[]) {
+    int res;
+
+    /* Setup io_uring for use */
+    if(app_setup_uring()) {
+        fprintf(stderr, "Unable to setup uring!\\n");
+        return 1;
+    }
+
+    /* 
+    * A while loop that reads from stdin and writes to stdout.
+    * Breaks on EOF.
+    */
+    while (1) {
+        /* Initiate read from stdin and wait for it to complete */
+        submit_to_sq(STDIN_FILENO, IORING_OP_READ);
+        /* Read completion queue entry */
+        res = read_from_cq();
+        if (res > 0) {
+            /* Read successful. Write to stdout. */
+            submit_to_sq(STDOUT_FILENO, IORING_OP_WRITE);
+            read_from_cq();
+        } else if (res == 0) {
+            /* reached EOF */
+            break;
+        }
+        else if (res < 0) {
+            /* Error reading file */
+            fprintf(stderr, "Error: %s\\n", strerror(abs(res)));
+            break;
+        }
+        offset += res;
+    }
+
+    return 0;
+}
+.EE
+.SH SEE ALSO
+.BR io_uring_enter (2)
+.BR io_uring_register (2)
+.BR io_uring_setup (2)
diff --git a/man/io_uring_enter.2 b/man/io_uring_enter.2
new file mode 100644
index 0000000..909cc9b
--- /dev/null
+++ b/man/io_uring_enter.2
@@ -0,0 +1,1158 @@
+.\" Copyright (C) 2019 Jens Axboe <axboe@kernel.dk>
+.\" Copyright (C) 2019 Red Hat, Inc.
+.\"
+.\" SPDX-License-Identifier: LGPL-2.0-or-later
+.\"
+.TH IO_URING_ENTER 2 2019-01-22 "Linux" "Linux Programmer's Manual"
+.SH NAME
+io_uring_enter \- initiate and/or complete asynchronous I/O
+.SH SYNOPSIS
+.nf
+.BR "#include <linux/io_uring.h>"
+.PP
+.BI "int io_uring_enter(unsigned int " fd ", unsigned int " to_submit ,
+.BI "                   unsigned int " min_complete ", unsigned int " flags ,
+.BI "                   sigset_t *" sig );
+.fi
+.PP
+.SH DESCRIPTION
+.PP
+.BR io_uring_enter ()
+is used to initiate and complete I/O using the shared submission and
+completion queues setup by a call to
+.BR io_uring_setup (2).
+A single call can both submit new I/O and wait for completions of I/O
+initiated by this call or previous calls to
+.BR io_uring_enter ().
+
+.I fd
+is the file descriptor returned by
+.BR io_uring_setup (2).
+.I to_submit
+specifies the number of I/Os to submit from the submission queue.
+.I flags
+is a bitmask of the following values:
+.TP
+.B IORING_ENTER_GETEVENTS
+If this flag is set, then the system call will wait for the specificied
+number of events in
+.I min_complete
+before returning. This flag can be set along with
+.I to_submit
+to both submit and complete events in a single system call.
+.TP
+.B IORING_ENTER_SQ_WAKEUP
+If the ring has been created with
+.B IORING_SETUP_SQPOLL,
+then this flag asks the kernel to wakeup the SQ kernel thread to submit IO.
+.TP
+.B IORING_ENTER_SQ_WAIT
+If the ring has been created with
+.B IORING_SETUP_SQPOLL,
+then the application has no real insight into when the SQ kernel thread has
+consumed entries from the SQ ring. This can lead to a situation where the
+application can no longer get a free SQE entry to submit, without knowing
+when it one becomes available as the SQ kernel thread consumes them. If
+the system call is used with this flag set, then it will wait until at least
+one entry is free in the SQ ring.
+.PP
+.PP
+If the io_uring instance was configured for polling, by specifying
+.B IORING_SETUP_IOPOLL
+in the call to
+.BR io_uring_setup (2),
+then min_complete has a slightly different meaning.  Passing a value
+of 0 instructs the kernel to return any events which are already complete,
+without blocking.  If
+.I min_complete
+is a non-zero value, the kernel will still return immediately if any
+completion events are available.  If no event completions are
+available, then the call will poll either until one or more
+completions become available, or until the process has exceeded its
+scheduler time slice.
+
+Note that, for interrupt driven I/O (where
+.B IORING_SETUP_IOPOLL
+was not specified in the call to
+.BR io_uring_setup (2)),
+an application may check the completion queue for event completions
+without entering the kernel at all.
+.PP
+When the system call returns that a certain amount of SQEs have been
+consumed and submitted, it's safe to reuse SQE entries in the ring. This is
+true even if the actual IO submission had to be punted to async context,
+which means that the SQE may in fact not have been submitted yet. If the
+kernel requires later use of a particular SQE entry, it will have made a
+private copy of it.
+
+.I sig
+is a pointer to a signal mask (see
+.BR sigprocmask (2));
+if
+.I sig
+is not NULL,
+.BR io_uring_enter ()
+first replaces the current signal mask by the one pointed to by
+.IR sig ,
+then waits for events to become available in the completion queue, and
+then restores the original signal mask.  The following
+.BR io_uring_enter ()
+call:
+.PP
+.in +4n
+.EX
+ret = io_uring_enter(fd, 0, 1, IORING_ENTER_GETEVENTS, &sig);
+.EE
+.in
+.PP
+is equivalent to
+.I atomically
+executing the following calls:
+.PP
+.in +4n
+.EX
+pthread_sigmask(SIG_SETMASK, &sig, &orig);
+ret = io_uring_enter(fd, 0, 1, IORING_ENTER_GETEVENTS, NULL);
+pthread_sigmask(SIG_SETMASK, &orig, NULL);
+.EE
+.in
+.PP
+See the description of
+.BR pselect (2)
+for an explanation of why the
+.I sig
+parameter is necessary.
+
+Submission queue entries are represented using the following data
+structure:
+.PP
+.in +4n
+.EX
+/*
+ * IO submission data structure (Submission Queue Entry)
+ */
+struct io_uring_sqe {
+    __u8    opcode;         /* type of operation for this sqe */
+    __u8    flags;          /* IOSQE_ flags */
+    __u16   ioprio;         /* ioprio for the request */
+    __s32   fd;             /* file descriptor to do IO on */
+    union {
+        __u64   off;            /* offset into file */
+        __u64   addr2;
+    };
+    union {
+        __u64   addr;       /* pointer to buffer or iovecs */
+        __u64   splice_off_in;
+    }
+    __u32   len;            /* buffer size or number of iovecs */
+    union {
+        __kernel_rwf_t  rw_flags;
+        __u32    fsync_flags;
+        __u16    poll_events;   /* compatibility */
+        __u32    poll32_events; /* word-reversed for BE */
+        __u32    sync_range_flags;
+        __u32    msg_flags;
+        __u32    timeout_flags;
+        __u32    accept_flags;
+        __u32    cancel_flags;
+        __u32    open_flags;
+        __u32    statx_flags;
+        __u32    fadvise_advice;
+        __u32    splice_flags;
+    };
+    __u64    user_data;     /* data to be passed back at completion time */
+    union {
+	struct {
+	    /* index into fixed buffers, if used */
+            union {
+                /* index into fixed buffers, if used */
+                __u16    buf_index;
+                /* for grouped buffer selection */
+                __u16    buf_group;
+            }
+	    /* personality to use, if used */
+	    __u16    personality;
+            __s32    splice_fd_in;
+	};
+        __u64    __pad2[3];
+    };
+};
+.EE
+.in
+.PP
+The
+.I opcode
+describes the operation to be performed.  It can be one of:
+.TP
+.B IORING_OP_NOP
+Do not perform any I/O.  This is useful for testing the performance of
+the io_uring implementation itself.
+.TP
+.B IORING_OP_READV
+.TP
+.B IORING_OP_WRITEV
+Vectored read and write operations, similar to
+.BR preadv2 (2)
+and
+.BR pwritev2 (2).
+If the file is not seekable,
+.I off
+must be set to zero.
+
+.TP
+.B IORING_OP_READ_FIXED
+.TP
+.B IORING_OP_WRITE_FIXED
+Read from or write to pre-mapped buffers.  See
+.BR io_uring_register (2)
+for details on how to setup a context for fixed reads and writes.
+
+.TP
+.B IORING_OP_FSYNC
+File sync.  See also
+.BR fsync (2).
+Note that, while I/O is initiated in the order in which it appears in
+the submission queue, completions are unordered.  For example, an
+application which places a write I/O followed by an fsync in the
+submission queue cannot expect the fsync to apply to the write.  The
+two operations execute in parallel, so the fsync may complete before
+the write is issued to the storage.  The same is also true for
+previously issued writes that have not completed prior to the fsync.
+
+.TP
+.B IORING_OP_POLL_ADD
+Poll the
+.I fd
+specified in the submission queue entry for the events
+specified in the
+.I poll_events
+field.  Unlike poll or epoll without
+.BR EPOLLONESHOT ,
+this interface always works in one shot mode.  That is, once the poll
+operation is completed, it will have to be resubmitted. This command works like
+an async
+.BR poll(2)
+and the completion event result is the returned mask of events.
+
+.TP
+.B IORING_OP_POLL_REMOVE
+Remove an existing poll request.  If found, the
+.I res
+field of the
+.I "struct io_uring_cqe"
+will contain 0.  If not found,
+.I res
+will contain
+.B -ENOENT.
+
+.TP
+.B IORING_OP_EPOLL_CTL
+Add, remove or modify entries in the interest list of
+.BR epoll (7).
+See
+.BR epoll_ctl (2)
+for details of the system call.
+.I fd
+holds the file descriptor that represents the epoll instance,
+.I addr
+holds the file descriptor to add, remove or modify,
+.I len
+holds the operation (EPOLL_CTL_ADD, EPOLL_CTL_DEL, EPOLL_CTL_MOD) to perform and,
+.I off
+holds a pointer to the
+.I epoll_events
+structure. Available since 5.6.
+
+.TP
+.B IORING_OP_SYNC_FILE_RANGE
+Issue the equivalent of a \fBsync_file_range\fR (2) on the file descriptor. The
+.I fd
+field is the file descriptor to sync, the
+.I off
+field holds the offset in bytes, the
+.I len
+field holds the length in bytes, and the
+.I sync_range_flags
+field holds the flags for the command. See also
+.BR sync_file_range (2)
+for the general description of the related system call. Available since 5.2.
+
+.TP
+.B IORING_OP_SENDMSG
+Issue the equivalent of a
+.BR sendmsg(2)
+system call.
+.I fd
+must be set to the socket file descriptor,
+.I addr
+must contain a pointer to the msghdr structure, and
+.I msg_flags
+holds the flags associated with the system call. See also
+.BR sendmsg (2)
+for the general description of the related system call. Available since 5.3.
+
+.TP
+.B IORING_OP_RECVMSG
+Works just like IORING_OP_SENDMSG, except for
+.BR recvmsg(2)
+instead. See the description of IORING_OP_SENDMSG. Available since 5.3.
+
+.TP
+.B IORING_OP_SEND
+Issue the equivalent of a
+.BR send(2)
+system call.
+.I fd
+must be set to the socket file descriptor,
+.I addr
+must contain a pointer to the buffer,
+.I len
+denotes the length of the buffer to send, and
+.I msg_flags
+holds the flags associated with the system call. See also
+.BR send(2)
+for the general description of the related system call. Available since 5.6.
+
+.TP
+.B IORING_OP_RECV
+Works just like IORING_OP_SEND, except for
+.BR recv(2)
+instead. See the description of IORING_OP_SEND. Available since 5.6.
+
+.TP
+.B IORING_OP_TIMEOUT
+This command will register a timeout operation. The
+.I addr
+field must contain a pointer to a struct timespec64 structure,
+.I len
+must contain 1 to signify one timespec64 structure,
+.I timeout_flags
+may contain IORING_TIMEOUT_ABS
+for an absolute timeout value, or 0 for a relative timeout.
+.I off
+may contain a completion event count. A timeout
+will trigger a wakeup event on the completion ring for anyone waiting for
+events. A timeout condition is met when either the specified timeout expires,
+or the specified number of events have completed. Either condition will
+trigger the event. If set to 0, completed events are not counted, which
+effectively acts like a timer. io_uring timeouts use the
+.B CLOCK_MONOTONIC
+clock source. The request will complete with
+.I -ETIME
+if the timeout got completed through expiration of the timer, or
+.I 0
+if the timeout got completed through requests completing on their own. If
+the timeout was cancelled before it expired, the request will complete with
+.I -ECANCELED.
+Available since 5.4.
+
+.TP
+.B IORING_OP_TIMEOUT_REMOVE
+If
+.I timeout_flags are zero, then it attempts to remove an existing timeout
+operation.
+.I addr
+must contain the
+.I user_data
+field of the previously issued timeout operation. If the specified timeout
+request is found and cancelled successfully, this request will terminate
+with a result value of
+.I 0
+If the timeout request was found but expiration was already in progress,
+this request will terminate with a result value of
+.I -EBUSY
+If the timeout request wasn't found, the request will terminate with a result
+value of
+.I -ENOENT
+Available since 5.5.
+
+If
+.I timeout_flags
+contain
+.I IORING_TIMEOUT_UPDATE,
+instead of removing an existing operation it updates it.
+.I addr
+and return values are same as before.
+.I addr2
+field must contain a pointer to a struct timespec64 structure.
+.I timeout_flags
+may also contain IORING_TIMEOUT_ABS.
+Available since 5.11.
+
+.TP
+.B IORING_OP_ACCEPT
+Issue the equivalent of an
+.BR accept4(2)
+system call.
+.I fd
+must be set to the socket file descriptor,
+.I addr
+must contain the pointer to the sockaddr structure, and
+.I addr2
+must contain a pointer to the socklen_t addrlen field. See also
+.BR accept4(2)
+for the general description of the related system call. Available since 5.5.
+
+.TP
+.B IORING_OP_ASYNC_CANCEL
+Attempt to cancel an already issued request.
+.I addr
+must contain the
+.I user_data
+field of the request that should be cancelled. The cancellation request will
+complete with one of the following results codes. If found, the
+.I res
+field of the cqe will contain 0. If not found,
+.I res
+will contain -ENOENT. If found and attempted cancelled, the
+.I res
+field will contain -EALREADY. In this case, the request may or may not
+terminate. In general, requests that are interruptible (like socket IO) will
+get cancelled, while disk IO requests cannot be cancelled if already started.
+Available since 5.5.
+
+.TP
+.B IORING_OP_LINK_TIMEOUT
+This request must be linked with another request through
+.I IOSQE_IO_LINK
+which is described below. Unlike
+.I IORING_OP_TIMEOUT,
+.I IORING_OP_LINK_TIMEOUT
+acts on the linked request, not the completion queue. The format of the command
+is otherwise like
+.I IORING_OP_TIMEOUT,
+except there's no completion event count as it's tied to a specific request.
+If used, the timeout specified in the command will cancel the linked command,
+unless the linked command completes before the timeout. The timeout will
+complete with
+.I -ETIME
+if the timer expired and the linked request was attempted cancelled, or
+.I -ECANCELED
+if the timer got cancelled because of completion of the linked request. Like
+.B IORING_OP_TIMEOUT
+the clock source used is
+.B CLOCK_MONOTONIC
+Available since 5.5.
+
+
+.TP
+.B IORING_OP_CONNECT
+Issue the equivalent of a
+.BR connect(2)
+system call.
+.I fd
+must be set to the socket file descriptor,
+.I addr
+must contain the const pointer to the sockaddr structure, and
+.I off
+must contain the socklen_t addrlen field. See also
+.BR connect(2)
+for the general description of the related system call. Available since 5.5.
+
+.TP
+.B IORING_OP_FALLOCATE
+Issue the equivalent of a
+.BR fallocate(2)
+system call.
+.I fd
+must be set to the file descriptor,
+.I len
+must contain the mode associated with the operation,
+.I off
+must contain the offset on which to operate, and
+.I addr
+must contain the length. See also
+.BR fallocate(2)
+for the general description of the related system call. Available since 5.6.
+
+.TP
+.B IORING_OP_FADVISE
+Issue the equivalent of a
+.BR posix_fadvise(2)
+system call.
+.I fd
+must be set to the file descriptor,
+.I off
+must contain the offset on which to operate,
+.I len
+must contain the length, and
+.I fadvise_advice
+must contain the advice associated with the operation. See also
+.BR posix_fadvise(2)
+for the general description of the related system call. Available since 5.6.
+
+.TP
+.B IORING_OP_MADVISE
+Issue the equivalent of a
+.BR madvise(2)
+system call.
+.I addr
+must contain the address to operate on,
+.I len
+must contain the length on which to operate,
+and
+.I fadvise_advice
+must contain the advice associated with the operation. See also
+.BR madvise(2)
+for the general description of the related system call. Available since 5.6.
+
+.TP
+.B IORING_OP_OPENAT
+Issue the equivalent of a
+.BR openat(2)
+system call.
+.I fd
+is the
+.I dirfd
+argument,
+.I addr
+must contain a pointer to the
+.I *pathname
+argument,
+.I open_flags
+should contain any flags passed in, and
+.I len
+is access mode of the file. See also
+.BR openat(2)
+for the general description of the related system call. Available since 5.6.
+
+.TP
+.B IORING_OP_OPENAT2
+Issue the equivalent of a
+.BR openat2(2)
+system call.
+.I fd
+is the
+.I dirfd
+argument,
+.I addr
+must contain a pointer to the
+.I *pathname
+argument,
+.I len
+should contain the size of the open_how structure, and
+.I off
+should be set to the address of the open_how structure. See also
+.BR openat2(2)
+for the general description of the related system call. Available since 5.6.
+
+.TP
+.B IORING_OP_CLOSE
+Issue the equivalent of a
+.BR close(2)
+system call.
+.I fd
+is the file descriptor to be closed. See also
+.BR close(2)
+for the general description of the related system call. Available since 5.6.
+
+.TP
+.B IORING_OP_STATX
+Issue the equivalent of a
+.BR statx(2)
+system call.
+.I fd
+is the
+.I dirfd
+argument,
+.I addr
+must contain a pointer to the
+.I *pathname
+string,
+.I statx_flags
+is the
+.I flags
+argument,
+.I len
+should be the
+.I mask
+argument, and
+.I off
+must contain a pointer to the
+.I statxbuf
+to be filled in. See also
+.BR statx(2)
+for the general description of the related system call. Available since 5.6.
+
+.TP
+.B IORING_OP_READ
+.TP
+.B IORING_OP_WRITE
+Issue the equivalent of a
+.BR pread(2)
+or
+.BR pwrite(2)
+system call.
+.I fd
+is the file descriptor to be operated on,
+.I addr
+contains the buffer in question,
+.I len
+contains the length of the IO operation, and
+.I offs
+contains the read or write offset. If
+.I fd
+does not refer to a seekable file,
+.I off
+must be set to zero. If
+.I offs
+is set to -1, the offset will use (and advance) the file position, like the
+.BR read(2)
+and
+.BR write(2)
+system calls. These are non-vectored versions of the
+.B IORING_OP_READV
+and
+.B IORING_OP_WRITEV
+opcodes. See also
+.BR read(2)
+and
+.BR write(2)
+for the general description of the related system call. Available since 5.6.
+
+.TP
+.B IORING_OP_SPLICE
+Issue the equivalent of a
+.BR splice(2)
+system call.
+.I splice_fd_in
+is the file descriptor to read from,
+.I splice_off_in
+is an offset to read from,
+.I fd
+is the file descriptor to write to,
+.I off
+is an offset from which to start writing to. A sentinel value of -1 is used
+to pass the equivalent of a NULL for the offsets to
+.BR splice(2).
+.I len
+contains the number of bytes to copy.
+.I splice_flags
+contains a bit mask for the flag field associated with the system call.
+Please note that one of the file descriptors must refer to a pipe.
+See also
+.BR splice(2)
+for the general description of the related system call. Available since 5.7.
+
+.TP
+.B IORING_OP_TEE
+Issue the equivalent of a
+.BR tee(2)
+system call.
+.I splice_fd_in
+is the file descriptor to read from,
+.I fd
+is the file descriptor to write to,
+.I len
+contains the number of bytes to copy, and
+.I splice_flags
+contains a bit mask for the flag field associated with the system call.
+Please note that both of the file descriptors must refer to a pipe.
+See also
+.BR tee(2)
+for the general description of the related system call. Available since 5.8.
+
+.TP
+.B IORING_OP_FILES_UPDATE
+This command is an alternative to using
+.B IORING_REGISTER_FILES_UPDATE
+which then works in an async fashion, like the rest of the io_uring commands.
+The arguments passed in are the same.
+.I addr
+must contain a pointer to the array of file descriptors,
+.I len
+must contain the length of the array, and
+.I off
+must contain the offset at which to operate. Note that the array of file
+descriptors pointed to in
+.I addr
+must remain valid until this operation has completed. Available since 5.6.
+
+.TP
+.B IORING_OP_PROVIDE_BUFFERS
+This command allows an application to register a group of buffers to be used
+by commands that read/receive data. Using buffers in this manner can eliminate
+the need to separate the poll + read, which provides a convenient point in
+time to allocate a buffer for a given request. It's often infeasible to have
+as many buffers available as pending reads or receive. With this feature, the
+application can have its pool of buffers ready in the kernel, and when the
+file or socket is ready to read/receive data, a buffer can be selected for the
+operation.
+.I fd
+must contain the number of buffers to provide,
+.I addr
+must contain the starting address to add buffers from,
+.I len
+must contain the length of each buffer to add from the range,
+.I buf_group
+must contain the group ID of this range of buffers, and
+.I off
+must contain the starting buffer ID of this range of buffers. With that set,
+the kernel adds buffers starting with the memory address in
+.I addr,
+each with a length of
+.I len.
+Hence the application should provide
+.I len * fd
+worth of memory in
+.I addr.
+Buffers are grouped by the group ID, and each buffer within this group will be
+identical in size according to the above arguments. This allows the application
+to provide different groups of buffers, and this is often used to have
+differently sized buffers available depending on what the expectations are of
+the individual request. When submitting a request that should use a provided
+buffer, the
+.B IOSQE_BUFFER_SELECT
+flag must be set, and
+.I buf_group
+must be set to the desired buffer group ID where the buffer should be selected
+from. Available since 5.7.
+
+.TP
+.B IORING_OP_REMOVE_BUFFERS
+Remove buffers previously registered with
+.B IORING_OP_PROVIDE_BUFFERS.
+.I fd
+must contain the number of buffers to remove, and
+.I buf_group
+must contain the buffer group ID from which to remove the buffers. Available
+since 5.7.
+
+.TP
+.B IORING_OP_SHUTDOWN
+Issue the equivalent of a
+.BR shutdown(2)
+system call.
+.I fd
+is the file descriptor to the socket being shutdown, no other fields should
+be set. Available since 5.11.
+
+.TP
+.B IORING_OP_RENAMEAT
+Issue the equivalent of a
+.BR renameat2(2)
+system call.
+.I fd
+should be set to the
+.I olddirfd,
+.I addr
+should be set to the
+.I oldpath,
+.I len
+should be set to the
+.I newdirfd,
+.I addr
+should be set to the
+.I oldpath,
+.I addr2
+should be set to the
+.I newpath,
+and finally
+.I rename_flags
+should be set to the
+.I flags
+passed in to
+.BR renameat2(2).
+Available since 5.11.
+
+.TP
+.B IORING_OP_UNLINKAT
+Issue the equivalent of a
+.BR unlinkat2(2)
+system call.
+.I fd
+should be set to the
+.I dirfd,
+.I addr
+should be set to the
+.I pathname,
+and
+.I unlink_flags
+should be set to the
+.I flags
+being passed in to
+.BR unlinkat(2).
+Available since 5.11.
+
+.PP
+The
+.I flags
+field is a bit mask. The supported flags are:
+.TP
+.B IOSQE_FIXED_FILE
+When this flag is specified,
+.I fd
+is an index into the files array registered with the io_uring instance (see the
+.B IORING_REGISTER_FILES
+section of the
+.BR io_uring_register (2)
+man page). Available since 5.1.
+.TP
+.B IOSQE_IO_DRAIN
+When this flag is specified, the SQE will not be started before previously
+submitted SQEs have completed, and new SQEs will not be started before this
+one completes. Available since 5.2.
+.TP
+.B IOSQE_IO_LINK
+When this flag is specified, it forms a link with the next SQE in the
+submission ring. That next SQE will not be started before this one completes.
+This, in effect, forms a chain of SQEs, which can be arbitrarily long. The tail
+of the chain is denoted by the first SQE that does not have this flag set.
+This flag has no effect on previous SQE submissions, nor does it impact SQEs
+that are outside of the chain tail. This means that multiple chains can be
+executing in parallel, or chains and individual SQEs. Only members inside the
+chain are serialized. A chain of SQEs will be broken, if any request in that
+chain ends in error. io_uring considers any unexpected result an error. This
+means that, eg, a short read will also terminate the remainder of the chain.
+If a chain of SQE links is broken, the remaining unstarted part of the chain
+will be terminated and completed with
+.B -ECANCELED
+as the error code. Available since 5.3.
+.TP
+.B IOSQE_IO_HARDLINK
+Like IOSQE_IO_LINK, but it doesn't sever regardless of the completion result.
+Note that the link will still sever if we fail submitting the parent request,
+hard links are only resilient in the presence of completion results for
+requests that did submit correctly. IOSQE_IO_HARDLINK implies IOSQE_IO_LINK.
+Available since 5.5.
+.TP
+.B IOSQE_ASYNC
+Normal operation for io_uring is to try and issue an sqe as non-blocking first,
+and if that fails, execute it in an async manner. To support more efficient
+overlapped operation of requests that the application knows/assumes will
+always (or most of the time) block, the application can ask for an sqe to be
+issued async from the start. Available since 5.6.
+.TP
+.B IOSQE_BUFFER_SELECT
+Used in conjunction with the
+.B IORING_OP_PROVIDE_BUFFERS
+command, which registers a pool of buffers to be used by commands that read
+or receive data. When buffers are registered for this use case, and this
+flag is set in the command, io_uring will grab a buffer from this pool when
+the request is ready to receive or read data. If succesful, the resulting CQE
+will have
+.B IORING_CQE_F_BUFFER
+set in the flags part of the struct, and the upper
+.B IORING_CQE_BUFFER_SHIFT
+bits will contain the ID of the selected buffers. This allows the application
+to know exactly which buffer was selected for the operation. If no buffers
+are available and this flag is set, then the request will fail with
+.B -ENOBUFS
+as the error code. Once a buffer has been used, it is no longer available in
+the kernel pool. The application must re-register the given buffer again when
+it is ready to recycle it (eg has completed using it). Available since 5.7.
+
+.PP
+.I ioprio
+specifies the I/O priority.  See
+.BR ioprio_get (2)
+for a description of Linux I/O priorities.
+
+.I fd
+specifies the file descriptor against which the operation will be
+performed, with the exception noted above.
+
+If the operation is one of
+.B IORING_OP_READ_FIXED
+or
+.BR IORING_OP_WRITE_FIXED ,
+.I addr
+and
+.I len
+must fall within the buffer located at
+.I buf_index
+in the fixed buffer array.  If the operation is either
+.B IORING_OP_READV
+or
+.BR IORING_OP_WRITEV ,
+then
+.I addr
+points to an iovec array of
+.I len
+entries.
+
+.IR rw_flags ,
+specified for read and write operations, contains a bitwise OR of
+per-I/O flags, as described in the
+.BR preadv2 (2)
+man page.
+
+The
+.I fsync_flags
+bit mask may contain either 0, for a normal file integrity sync, or
+.B IORING_FSYNC_DATASYNC
+to provide data sync only semantics.  See the descriptions of
+.B O_SYNC
+and
+.B O_DSYNC
+in the
+.BR open (2)
+manual page for more information.
+
+The bits that may be set in
+.I poll_events
+are defined in \fI<poll.h>\fP, and documented in
+.BR poll (2).
+
+.I user_data
+is an application-supplied value that will be copied into
+the completion queue entry (see below).
+.I buf_index
+is an index into an array of fixed buffers, and is only valid if fixed
+buffers were registered.
+.I personality
+is the credentials id to use for this operation. See
+.BR io_uring_register(2)
+for how to register personalities with io_uring. If set to 0, the current
+personality of the submitting task is used.
+.PP
+Once the submission queue entry is initialized, I/O is submitted by
+placing the index of the submission queue entry into the tail of the
+submission queue.  After one or more indexes are added to the queue,
+and the queue tail is advanced, the
+.BR io_uring_enter (2)
+system call can be invoked to initiate the I/O.
+
+Completions use the following data structure:
+.PP
+.in +4n
+.EX
+/*
+ * IO completion data structure (Completion Queue Entry)
+ */
+struct io_uring_cqe {
+    __u64    user_data; /* sqe->data submission passed back */
+    __s32    res;       /* result code for this event */
+    __u32    flags;
+};
+.EE
+.in
+.PP
+.I user_data
+is copied from the field of the same name in the submission queue
+entry.  The primary use case is to store data that the application
+will need to access upon completion of this particular I/O.  The
+.I flags
+is reserved for future use.
+.I res
+is the operation-specific result, but io_uring-specific errors
+(e.g. flags or opcode invalid) are returned through this field.
+They are described in section
+.B CQE ERRORS.
+.PP
+For read and write opcodes, the
+return values match those documented in the
+.BR preadv2 (2)
+and
+.BR pwritev2 (2)
+man pages.
+Return codes for the io_uring-specific opcodes are documented in the
+description of the opcodes above.
+.PP
+.SH RETURN VALUE
+.BR io_uring_enter ()
+returns the number of I/Os successfully consumed.  This can be zero
+if
+.I to_submit
+was zero or if the submission queue was empty. Note that if the ring was
+created with
+.B IORING_SETUP_SQPOLL
+specified, then the return value will generally be the same as
+.I to_submit
+as submission happens outside the context of the system call.
+
+The errors related to a submission queue entry will be returned through a
+completion queue entry (see section
+.B CQE ERRORS),
+rather than through the system call itself.
+
+Errors that occur not on behalf of a submission queue entry are returned via the
+system call directly. On such an error, -1 is returned and
+.I errno
+is set appropriately.
+.PP
+.SH ERRORS
+These are the errors returned by
+.BR io_uring_enter ()
+system call.
+.TP
+.B EAGAIN
+The kernel was unable to allocate memory for the request, or otherwise ran out
+of resources to handle it. The application should wait for some completions and
+try again.
+.TP
+.B EBADF
+.I fd
+is not a valid file descriptor.
+.TP
+.B EBADFD
+.I fd
+is a valid file descriptor, but the io_uring ring is not in the right state
+(enabled). See
+.BR io_uring_register (2)
+for details on how to enable the ring.
+.TP
+.B EBUSY
+The application is attempting to overcommit the number of requests it can have
+pending. The application should wait for some completions and try again. May
+occur if the application tries to queue more requests than we have room for in
+the CQ ring, or if the application attempts to wait for more events without
+having reaped the ones already present in the CQ ring.
+.TP
+.B EINVAL
+Some bits in the
+.I flags
+argument are invalid.
+.TP
+.B EFAULT
+An invalid user space address was specified for the
+.I sig
+argument.
+.TP
+.B ENXIO
+The io_uring instance is in the process of being torn down.
+.TP
+.B EOPNOTSUPP
+.I fd
+does not refer to an io_uring instance.
+.TP
+.B EINTR
+The operation was interrupted by a delivery of a signal before it could
+complete; see
+.BR signal(7).
+Can happen while waiting for events with
+.B IORING_ENTER_GETEVENTS.
+
+.SH CQE ERRORS
+These io_uring-specific errors are returned as a negative value in the
+.I res
+field of the completion queue entry.
+.TP
+.B EACCES
+The
+.I flags
+field or
+.I opcode
+in a submission queue entry is not allowed due to registered restrictions.
+See
+.BR io_uring_register (2)
+for details on how restrictions work.
+.TP
+.B EBADF
+The
+.I fd
+field in the submission queue entry is invalid, or the
+.B IOSQE_FIXED_FILE
+flag was set in the submission queue entry, but no files were registered
+with the io_uring instance.
+.TP
+.B EFAULT
+buffer is outside of the process' accessible address space
+.TP
+.B EFAULT
+.B IORING_OP_READ_FIXED
+or
+.B IORING_OP_WRITE_FIXED
+was specified in the
+.I opcode
+field of the submission queue entry, but either buffers were not
+registered for this io_uring instance, or the address range described
+by
+.I addr
+and
+.I len
+does not fit within the buffer registered at
+.IR buf_index .
+.TP
+.B EINVAL
+The
+.I flags
+field or
+.I opcode
+in a submission queue entry is invalid.
+.TP
+.B EINVAL
+The
+.I buf_index
+member of the submission queue entry is invalid.
+.TP
+.B EINVAL
+The
+.I personality
+field in a submission queue entry is invalid.
+.TP
+.B EINVAL
+.B IORING_OP_NOP
+was specified in the submission queue entry, but the io_uring context
+was setup for polling
+.RB ( IORING_SETUP_IOPOLL
+was specified in the call to io_uring_setup).
+.TP
+.B EINVAL
+.B IORING_OP_READV
+or
+.B IORING_OP_WRITEV
+was specified in the submission queue entry, but the io_uring instance
+has fixed buffers registered.
+.TP
+.B EINVAL
+.B IORING_OP_READ_FIXED
+or
+.B IORING_OP_WRITE_FIXED
+was specified in the submission queue entry, and the
+.I buf_index
+is invalid.
+.TP
+.B EINVAL
+.BR IORING_OP_READV ,
+.BR IORING_OP_WRITEV ,
+.BR IORING_OP_READ_FIXED ,
+.B IORING_OP_WRITE_FIXED
+or
+.B IORING_OP_FSYNC
+was specified in the submission queue entry, but the io_uring instance
+was configured for IOPOLLing, or any of
+.IR addr ,
+.IR ioprio ,
+.IR off ,
+.IR len ,
+or
+.I buf_index
+was set in the submission queue entry.
+.TP
+.B EINVAL
+.B IORING_OP_POLL_ADD
+or
+.B IORING_OP_POLL_REMOVE
+was specified in the
+.I opcode
+field of the submission queue entry, but the io_uring instance was
+configured for busy-wait polling
+.RB ( IORING_SETUP_IOPOLL ),
+or any of
+.IR ioprio ,
+.IR off ,
+.IR len ,
+or
+.I buf_index
+was non-zero in the submission queue entry.
+.TP
+.B EINVAL
+.B IORING_OP_POLL_ADD
+was specified in the
+.I opcode
+field of the submission queue entry, and the
+.I addr
+field was non-zero.
+.TP
+.B EOPNOTSUPP
+.I opcode
+is valid, but not supported by this kernel.
+.TP
+.B EOPNOTSUPP
+.B IOSQE_BUFFER_SELECT
+was set in the
+.I flags
+field of the submission queue entry, but the
+.I opcode
+doesn't support buffer selection.
diff --git a/man/io_uring_get_sqe.3 b/man/io_uring_get_sqe.3
new file mode 100644
index 0000000..24834f3
--- /dev/null
+++ b/man/io_uring_get_sqe.3
@@ -0,0 +1,37 @@
+.\" Copyright (C) 2020 Jens Axboe <axboe@kernel.dk>
+.\" Copyright (C) 2020 Red Hat, Inc.
+.\"
+.\" SPDX-License-Identifier: LGPL-2.0-or-later
+.\"
+.TH io_uring_get_sqe 3 "July 10, 2020" "liburing-0.7" "liburing Manual"
+.SH NAME
+io_uring_get_sqe - get the next vacant event from the submission queue
+.SH SYNOPSIS
+.nf
+.BR "#include <liburing.h>"
+.PP
+.BI "struct io_uring_sqe *io_uring_get_sqe(struct io_uring " *ring );
+.fi
+.PP
+.SH DESCRIPTION
+.PP
+The io_uring_get_sqe() function gets the next vacant event from the submission
+queue belonging to the
+.I ring
+param.
+
+On success io_uring_get_sqe() returns a pointer to the submission queue event.
+On failure NULL is returned.
+
+If a submission queue event is returned, it should be filled out via one of the
+prep functions such as
+.BR io_uring_prep_read (3)
+and submitted via
+.BR io_uring_submit (3).
+
+.SH RETURN VALUE
+.BR io_uring_get_sqe (3)
+returns a pointer to the next submission queue event on success and NULL on
+failure.
+.SH SEE ALSO
+.BR io_uring_submit (3)
diff --git a/man/io_uring_queue_exit.3 b/man/io_uring_queue_exit.3
new file mode 100644
index 0000000..294b5f3
--- /dev/null
+++ b/man/io_uring_queue_exit.3
@@ -0,0 +1,27 @@
+.\" Copyright (C) 2020 Jens Axboe <axboe@kernel.dk>
+.\" Copyright (C) 2020 Red Hat, Inc.
+.\"
+.\" SPDX-License-Identifier: LGPL-2.0-or-later
+.\"
+.TH io_uring_queue_exit 3 "July 10, 2020" "liburing-0.7" "liburing Manual"
+.SH NAME
+io_uring_queue_exit - tear down io_uring submission and completion queues
+.SH SYNOPSIS
+.nf
+.BR "#include <liburing.h>"
+.PP
+.BI "void io_uring_queue_exit(struct io_uring * ring );"
+.fi
+.PP
+.SH DESCRIPTION
+.PP
+.BR io_uring_queue_exit (3)
+will release all resources acquired and initialized by
+.BR io_uring_queue_init (3).
+It first unmaps the memory shared between the application and the kernel and then closes the io_uring file descriptor.
+.SH RETURN VALUE
+None
+.SH SEE ALSO
+.BR io_uring_setup (2),
+.BR mmap (2),
+.BR io_uring_queue_init (3)
diff --git a/man/io_uring_queue_init.3 b/man/io_uring_queue_init.3
new file mode 100644
index 0000000..1980fa4
--- /dev/null
+++ b/man/io_uring_queue_init.3
@@ -0,0 +1,44 @@
+.\" Copyright (C) 2020 Jens Axboe <axboe@kernel.dk>
+.\" Copyright (C) 2020 Red Hat, Inc.
+.\"
+.\" SPDX-License-Identifier: LGPL-2.0-or-later
+.\"
+.TH io_uring_queue_init 3 "July 10, 2020" "liburing-0.7" "liburing Manual"
+.SH NAME
+io_uring_queue_init - setup io_uring submission and completion queues
+.SH SYNOPSIS
+.nf
+.BR "#include <liburing.h>"
+.PP
+.BI "int io_uring_queue_init(unsigned " entries ", struct io_uring *" ring ,
+.BI "                        unsigned " flags );
+.fi
+.PP
+.SH DESCRIPTION
+.PP
+The io_uring_queue_init() function executes the io_uring_setup syscall to
+initialize the submission and completion queues in the kernel with at least
+.I entries
+entries and then maps the resulting file descriptor to memory shared between the
+application and the kernel.
+
+On success io_uring_queue_init() returns 0 and
+.I ring
+will point to the shared memory containing the io_uring queues. On failure
+-errno is returned.
+
+.I flags
+will be passed through to the io_uring_setup syscall (see 
+.BR io_uring_setup (2)).
+
+On success, the resources held by
+.I ring
+should be released via a corresponding call to
+.BR io_uring_queue_exit (3).
+.SH RETURN VALUE
+.BR io_uring_queue_init (3)
+returns 0 on success and -errno on failure.
+.SH SEE ALSO
+.BR io_uring_setup (2),
+.BR mmap (2),
+.BR io_uring_queue_exit (3)
diff --git a/man/io_uring_register.2 b/man/io_uring_register.2
new file mode 100644
index 0000000..5326a87
--- /dev/null
+++ b/man/io_uring_register.2
@@ -0,0 +1,405 @@
+.\" Copyright (C) 2019 Jens Axboe <axboe@kernel.dk>
+.\" Copyright (C) 2019 Red Hat, Inc.
+.\"
+.\" SPDX-License-Identifier: LGPL-2.0-or-later
+.\"
+.TH IO_URING_REGISTER 2 2019-01-17 "Linux" "Linux Programmer's Manual"
+.SH NAME
+io_uring_register \- register files or user buffers for asynchronous I/O 
+.SH SYNOPSIS
+.nf
+.BR "#include <linux/io_uring.h>"
+.PP
+.BI "int io_uring_register(unsigned int " fd ", unsigned int " opcode ,
+.BI "                      void *" arg ", unsigned int " nr_args );
+.fi
+.PP
+.SH DESCRIPTION
+.PP
+
+The
+.BR io_uring_register ()
+system call registers resources (e.g. user buffers, files, eventfd,
+personality, restrictions) for use in an
+.BR io_uring (7)
+instance referenced by
+.IR fd .
+Registering files or user buffers allows the kernel to take long term
+references to internal data structures or create long term mappings of
+application memory, greatly reducing per-I/O overhead.
+
+.I fd
+is the file descriptor returned by a call to
+.BR io_uring_setup (2).
+.I opcode
+can be one of:
+
+.TP
+.B IORING_REGISTER_BUFFERS
+.I arg
+points to a
+.I struct iovec
+array of
+.I nr_args
+entries.  The buffers associated with the iovecs will be locked in
+memory and charged against the user's
+.B RLIMIT_MEMLOCK
+resource limit.  See
+.BR getrlimit (2)
+for more information.  Additionally, there is a size limit of 1GiB per
+buffer.  Currently, the buffers must be anonymous, non-file-backed
+memory, such as that returned by
+.BR malloc (3)
+or
+.BR mmap (2)
+with the
+.B MAP_ANONYMOUS
+flag set.  It is expected that this limitation will be lifted in the
+future. Huge pages are supported as well. Note that the entire huge
+page will be pinned in the kernel, even if only a portion of it is
+used.
+
+After a successful call, the supplied buffers are mapped into the
+kernel and eligible for I/O.  To make use of them, the application
+must specify the
+.B IORING_OP_READ_FIXED
+or
+.B IORING_OP_WRITE_FIXED
+opcodes in the submission queue entry (see the
+.I struct io_uring_sqe
+definition in
+.BR io_uring_enter (2)),
+and set the
+.I buf_index
+field to the desired buffer index.  The memory range described by the
+submission queue entry's
+.I addr
+and
+.I len
+fields must fall within the indexed buffer.
+
+It is perfectly valid to setup a large buffer and then only use part
+of it for an I/O, as long as the range is within the originally mapped
+region.
+
+An application can increase or decrease the size or number of
+registered buffers by first unregistering the existing buffers, and
+then issuing a new call to
+.BR io_uring_register ()
+with the new buffers.
+
+Note that registering buffers will wait for the ring to idle. If the application
+currently has requests in-flight, the registration will wait for those to
+finish before proceeding.
+
+An application need not unregister buffers explicitly before shutting
+down the io_uring instance. Available since 5.1.
+
+.TP
+.B IORING_UNREGISTER_BUFFERS
+This operation takes no argument, and
+.I arg
+must be passed as NULL.  All previously registered buffers associated
+with the io_uring instance will be released. Available since 5.1.
+
+.TP
+.B IORING_REGISTER_FILES
+Register files for I/O.
+.I arg
+contains a pointer to an array of
+.I nr_args
+file descriptors (signed 32 bit integers).
+
+To make use of the registered files, the
+.B IOSQE_FIXED_FILE
+flag must be set in the
+.I flags
+member of the
+.IR "struct io_uring_sqe" ,
+and the
+.I fd
+member is set to the index of the file in the file descriptor array.
+
+The file set may be sparse, meaning that the
+.B fd
+field in the array may be set to
+.B -1.
+See
+.B IORING_REGISTER_FILES_UPDATE
+for how to update files in place.
+
+Note that registering files will wait for the ring to idle. If the application
+currently has requests in-flight, the registration will wait for those to
+finish before proceeding. See
+.B IORING_REGISTER_FILES_UPDATE
+for how to update an existing set without that limitation.
+
+Files are automatically unregistered when the io_uring instance is
+torn down. An application need only unregister if it wishes to
+register a new set of fds. Available since 5.1.
+
+.TP
+.B IORING_REGISTER_FILES_UPDATE
+This operation replaces existing files in the registered file set with new
+ones, either turning a sparse entry (one where fd is equal to -1) into a
+real one, removing an existing entry (new one is set to -1), or replacing
+an existing entry with a new existing entry.
+
+.I arg
+must contain a pointer to a struct io_uring_files_update, which contains
+an offset on which to start the update, and an array of file descriptors to
+use for the update.
+.I nr_args
+must contain the number of descriptors in the passed in array. Available
+since 5.5.
+
+File descriptors can be skipped if they are set to
+.B IORING_REGISTER_FILES_SKIP.
+Skipping an fd will not touch the file associated with the previous
+fd at that index. Available since 5.12.
+
+
+.TP
+.B IORING_UNREGISTER_FILES
+This operation requires no argument, and
+.I arg
+must be passed as NULL.  All previously registered files associated
+with the io_uring instance will be unregistered. Available since 5.1.
+
+.TP
+.B IORING_REGISTER_EVENTFD
+It's possible to use eventfd(2) to get notified of completion events on an
+io_uring instance. If this is desired, an eventfd file descriptor can be
+registered through this operation.
+.I arg
+must contain a pointer to the eventfd file descriptor, and
+.I nr_args
+must be 1. Available since 5.2.
+
+An application can temporarily disable notifications, coming through the
+registered eventfd, by setting the
+.B IORING_CQ_EVENTFD_DISABLED
+bit in the
+.I flags
+field of the CQ ring.
+Available since 5.8.
+
+.TP
+.B IORING_REGISTER_EVENTFD_ASYNC
+This works just like
+.B IORING_REGISTER_EVENTFD
+, except notifications are only posted for events that complete in an async
+manner. This means that events that complete inline while being submitted
+do not trigger a notification event. The arguments supplied are the same as
+for
+.B IORING_REGISTER_EVENTFD.
+Available since 5.6.
+
+.TP
+.B IORING_UNREGISTER_EVENTFD
+Unregister an eventfd file descriptor to stop notifications. Since only one
+eventfd descriptor is currently supported, this operation takes no argument,
+and
+.I arg
+must be passed as NULL and
+.I nr_args
+must be zero. Available since 5.2.
+
+.TP
+.B IORING_REGISTER_PROBE
+This operation returns a structure, io_uring_probe, which contains information
+about the opcodes supported by io_uring on the running kernel.
+.I arg
+must contain a pointer to a struct io_uring_probe, and
+.I nr_args
+must contain the size of the ops array in that probe struct. The ops array
+is of the type io_uring_probe_op, which holds the value of the opcode and
+a flags field. If the flags field has
+.B IO_URING_OP_SUPPORTED
+set, then this opcode is supported on the running kernel. Available since 5.6.
+
+.TP
+.B IORING_REGISTER_PERSONALITY
+This operation registers credentials of the running application with io_uring,
+and returns an id associated with these credentials. Applications wishing to
+share a ring between separate users/processes can pass in this credential id
+in the sqe
+.B personality
+field. If set, that particular sqe will be issued with these credentials. Must
+be invoked with
+.I arg
+set to NULL and
+.I nr_args
+set to zero. Available since 5.6.
+
+.TP
+.B IORING_UNREGISTER_PERSONALITY
+This operation unregisters a previously registered personality with io_uring.
+.I nr_args
+must be set to the id in question, and
+.I arg
+must be set to NULL. Available since 5.6.
+
+.TP
+.B IORING_REGISTER_ENABLE_RINGS
+This operation enables an io_uring ring started in a disabled state
+.RB (IORING_SETUP_R_DISABLED
+was specified in the call to
+.BR io_uring_setup (2)).
+While the io_uring ring is disabled, submissions are not allowed and
+registrations are not restricted.
+
+After the execution of this operation, the io_uring ring is enabled:
+submissions and registration are allowed, but they will
+be validated following the registered restrictions (if any).
+This operation takes no argument, must be invoked with
+.I arg
+set to NULL and
+.I nr_args
+set to zero. Available since 5.10.
+
+.TP
+.B IORING_REGISTER_RESTRICTIONS
+.I arg
+points to a
+.I struct io_uring_restriction
+array of
+.I nr_args
+entries.
+
+With an entry it is possible to allow an
+.BR io_uring_register ()
+.I opcode,
+or specify which
+.I opcode
+and
+.I flags
+of the submission queue entry are allowed,
+or require certain
+.I flags
+to be specified (these flags must be set on each submission queue entry).
+
+All the restrictions must be submitted with a single
+.BR io_uring_register ()
+call and they are handled as an allowlist (opcodes and flags not registered,
+are not allowed).
+
+Restrictions can be registered only if the io_uring ring started in a disabled
+state
+.RB (IORING_SETUP_R_DISABLED
+must be specified in the call to
+.BR io_uring_setup (2)).
+
+Available since 5.10.
+
+.SH RETURN VALUE
+
+On success,
+.BR io_uring_register ()
+returns 0.  On error, -1 is returned, and
+.I errno
+is set accordingly.
+
+.SH ERRORS
+.TP
+.B EACCES
+The
+.I opcode
+field is not allowed due to registered restrictions.
+.TP
+.B EBADF
+One or more fds in the
+.I fd
+array are invalid.
+.TP
+.B EBADFD
+.B IORING_REGISTER_ENABLE_RINGS
+or
+.B IORING_REGISTER_RESTRICTIONS
+was specified, but the io_uring ring is not disabled.
+.TP
+.B EBUSY
+.B IORING_REGISTER_BUFFERS
+or
+.B IORING_REGISTER_FILES
+or
+.B IORING_REGISTER_RESTRICTIONS
+was specified, but there were already buffers, files, or restrictions
+registered.
+.TP
+.B EFAULT
+buffer is outside of the process' accessible address space, or
+.I iov_len
+is greater than 1GiB.
+.TP
+.B EINVAL
+.B IORING_REGISTER_BUFFERS
+or
+.B IORING_REGISTER_FILES
+was specified, but
+.I nr_args
+is 0.
+.TP
+.B EINVAL
+.B IORING_REGISTER_BUFFERS
+was specified, but
+.I nr_args
+exceeds
+.B UIO_MAXIOV
+.TP
+.B EINVAL
+.B IORING_UNREGISTER_BUFFERS
+or
+.B IORING_UNREGISTER_FILES
+was specified, and
+.I nr_args
+is non-zero or
+.I arg
+is non-NULL.
+.TP
+.B EINVAL
+.B IORING_REGISTER_RESTRICTIONS
+was specified, but
+.I nr_args
+exceeds the maximum allowed number of restrictions or restriction
+.I opcode
+is invalid.
+.TP
+.B EMFILE
+.B IORING_REGISTER_FILES
+was specified and
+.I nr_args
+exceeds the maximum allowed number of files in a fixed file set.
+.TP
+.B EMFILE
+.B IORING_REGISTER_FILES
+was specified and adding
+.I nr_args
+file references would exceed the maximum allowed number of files the user
+is allowed to have according to the
+.B
+RLIMIT_NOFILE
+resource limit and the caller does not have
+.B CAP_SYS_RESOURCE
+capability. Note that this is a per user limit, not per process.
+.TP
+.B ENOMEM
+Insufficient kernel resources are available, or the caller had a
+non-zero
+.B RLIMIT_MEMLOCK
+soft resource limit, but tried to lock more memory than the limit
+permitted.  This limit is not enforced if the process is privileged
+.RB ( CAP_IPC_LOCK ).
+.TP
+.B ENXIO
+.B IORING_UNREGISTER_BUFFERS
+or
+.B IORING_UNREGISTER_FILES
+was specified, but there were no buffers or files registered.
+.TP
+.B ENXIO
+Attempt to register files or buffers on an io_uring instance that is already
+undergoing file or buffer registration, or is being torn down.
+.TP
+.B EOPNOTSUPP
+User buffers point to file-backed memory.
diff --git a/man/io_uring_setup.2 b/man/io_uring_setup.2
new file mode 100644
index 0000000..cb8eba9
--- /dev/null
+++ b/man/io_uring_setup.2
@@ -0,0 +1,471 @@
+.\" Copyright (C) 2019 Jens Axboe <axboe@kernel.dk>
+.\" Copyright (C) 2019 Jon Corbet <corbet@lwn.net>
+.\" Copyright (C) 2019 Red Hat, Inc.
+.\"
+.\" SPDX-License-Identifier: LGPL-2.0-or-later
+.\"
+.TH IO_URING_SETUP 2 2019-01-29 "Linux" "Linux Programmer's Manual"
+.SH NAME
+io_uring_setup \- setup a context for performing asynchronous I/O
+.SH SYNOPSIS
+.nf
+.BR "#include <linux/io_uring.h>"
+.PP
+.BI "int io_uring_setup(u32 " entries ", struct io_uring_params *" p );
+.fi
+.PP
+.SH DESCRIPTION
+.PP
+The io_uring_setup() system call sets up a submission queue (SQ) and
+completion queue (CQ) with at least
+.I entries
+entries, and returns a file descriptor which can be used to perform
+subsequent operations on the io_uring instance.  The submission and
+completion queues are shared between userspace and the kernel, which
+eliminates the need to copy data when initiating and completing I/O.
+
+.I params
+is used by the application to pass options to the kernel, and by the
+kernel to convey information about the ring buffers.
+.PP
+.in +4n
+.EX
+struct io_uring_params {
+    __u32 sq_entries;
+    __u32 cq_entries;
+    __u32 flags;
+    __u32 sq_thread_cpu;
+    __u32 sq_thread_idle;
+    __u32 features;
+    __u32 resv[4];
+    struct io_sqring_offsets sq_off;
+    struct io_cqring_offsets cq_off;
+};
+.EE
+.in
+.PP
+The
+.IR flags ,
+.IR sq_thread_cpu ,
+and
+.I sq_thread_idle
+fields are used to configure the io_uring instance.
+.I flags
+is a bit mask of 0 or more of the following values ORed
+together:
+.TP
+.B IORING_SETUP_IOPOLL
+Perform busy-waiting for an I/O completion, as opposed to getting
+notifications via an asynchronous IRQ (Interrupt Request).  The file
+system (if any) and block device must support polling in order for
+this to work.  Busy-waiting provides lower latency, but may consume
+more CPU resources than interrupt driven I/O.  Currently, this feature
+is usable only on a file descriptor opened using the
+.B O_DIRECT
+flag.  When a read or write is submitted to a polled context, the
+application must poll for completions on the CQ ring by calling
+.BR io_uring_enter (2).
+It is illegal to mix and match polled and non-polled I/O on an io_uring
+instance.
+
+.TP
+.B IORING_SETUP_SQPOLL
+When this flag is specified, a kernel thread is created to perform
+submission queue polling.  An io_uring instance configured in this way
+enables an application to issue I/O without ever context switching
+into the kernel.  By using the submission queue to fill in new
+submission queue entries and watching for completions on the
+completion queue, the application can submit and reap I/Os without
+doing a single system call.
+
+If the kernel thread is idle for more than
+.I sq_thread_idle
+milliseconds, it will set the
+.B IORING_SQ_NEED_WAKEUP
+bit in the
+.I flags
+field of the
+.IR "struct io_sq_ring" .
+When this happens, the application must call
+.BR io_uring_enter (2)
+to wake the kernel thread.  If I/O is kept busy, the kernel thread
+will never sleep.  An application making use of this feature will need
+to guard the
+.BR io_uring_enter (2)
+call with the following code sequence:
+
+.in +4n
+.EX
+/*
+ * Ensure that the wakeup flag is read after the tail pointer
+ * has been written. It's important to use memory load acquire
+ * semantics for the flags read, as otherwise the application
+ * and the kernel might not agree on the consistency of the
+ * wakeup flag.
+ */
+unsigned flags = atomic_load_relaxed(sq_ring->flags);
+if (flags & IORING_SQ_NEED_WAKEUP)
+    io_uring_enter(fd, 0, 0, IORING_ENTER_SQ_WAKEUP);
+.EE
+.in
+
+where
+.I sq_ring
+is a submission queue ring setup using the
+.I struct io_sqring_offsets
+described below.
+.TP
+.BR
+Before version 5.11 of the Linux kernel, to successfully use this feature, the
+application must register a set of files to be used for IO through
+.BR io_uring_register (2)
+using the
+.B IORING_REGISTER_FILES
+opcode. Failure to do so will result in submitted IO being errored with
+.B EBADF.
+The presence of this feature can be detected by the
+.B IORING_FEAT_SQPOLL_NONFIXED
+feature flag.
+In version 5.11 and later, it is no longer necessary to register files to use
+this feature. 5.11 also allows using this as non-root, if the user has the
+.B CAP_SYS_NICE
+capability.
+.TP
+.B IORING_SETUP_SQ_AFF
+If this flag is specified, then the poll thread will be bound to the
+cpu set in the
+.I sq_thread_cpu
+field of the
+.IR "struct io_uring_params" .
+This flag is only meaningful when
+.B IORING_SETUP_SQPOLL
+is specified. When cgroup setting
+.I cpuset.cpus
+changes (typically in container environment), the bounded cpu set may be
+changed as well.
+.TP
+.B IORING_SETUP_CQSIZE
+Create the completion queue with
+.IR "struct io_uring_params.cq_entries"
+entries.  The value must be greater than
+.IR entries ,
+and may be rounded up to the next power-of-two.
+.TP
+.B IORING_SETUP_CLAMP
+If this flag is specified, and if
+.IR entries
+exceeds
+.B IORING_MAX_ENTRIES ,
+then
+.IR entries
+will be clamped at
+.B IORING_MAX_ENTRIES .
+If the flag
+.BR IORING_SETUP_SQPOLL
+is set, and if the value of
+.IR "struct io_uring_params.cq_entries"
+exceeds
+.B IORING_MAX_CQ_ENTRIES ,
+then it will be clamped at
+.B IORING_MAX_CQ_ENTRIES .
+.TP
+.B IORING_SETUP_ATTACH_WQ
+This flag should be set in conjunction with 
+.IR "struct io_uring_params.wq_fd"
+being set to an existing io_uring ring file descriptor. When set, the
+io_uring instance being created will share the asynchronous worker
+thread backend of the specified io_uring ring, rather than create a new
+separate thread pool.
+.TP
+.B IORING_SETUP_R_DISABLED
+If this flag is specified, the io_uring ring starts in a disabled state.
+In this state, restrictions can be registered, but submissions are not allowed.
+See
+.BR io_uring_register (2)
+for details on how to enable the ring. Available since 5.10.
+.PP
+If no flags are specified, the io_uring instance is setup for
+interrupt driven I/O.  I/O may be submitted using
+.BR io_uring_enter (2)
+and can be reaped by polling the completion queue.
+
+The
+.I resv
+array must be initialized to zero.
+
+.I features
+is filled in by the kernel, which specifies various features supported
+by current kernel version.
+.TP
+.B IORING_FEAT_SINGLE_MMAP
+If this flag is set, the two SQ and CQ rings can be mapped with a single
+.I mmap(2)
+call. The SQEs must still be allocated separately. This brings the necessary
+.I mmap(2)
+calls down from three to two.
+.TP
+.B IORING_FEAT_NODROP
+If this flag is set, io_uring supports never dropping completion events.
+If a completion event occurs and the CQ ring is full, the kernel stores
+the event internally until such a time that the CQ ring has room for more
+entries. If this overflow condition is entered, attempting to submit more
+IO with fail with the
+.B -EBUSY
+error value, if it can't flush the overflown events to the CQ ring. If this
+happens, the application must reap events from the CQ ring and attempt the
+submit again.
+.TP
+.B IORING_FEAT_SUBMIT_STABLE
+If this flag is set, applications can be certain that any data for
+async offload has been consumed when the kernel has consumed the SQE.
+.TP
+.B IORING_FEAT_RW_CUR_POS
+If this flag is set, applications can specify
+.I offset
+== -1 with
+.B IORING_OP_{READV,WRITEV}
+,
+.B IORING_OP_{READ,WRITE}_FIXED
+, and
+.B IORING_OP_{READ,WRITE}
+to mean current file position, which behaves like
+.I preadv2(2)
+and
+.I pwritev2(2)
+with
+.I offset
+== -1. It'll use (and update) the current file position. This obviously comes
+with the caveat that if the application has multiple reads or writes in flight,
+then the end result will not be as expected. This is similar to threads sharing
+a file descriptor and doing IO using the current file position.
+.TP
+.B IORING_FEAT_CUR_PERSONALITY
+If this flag is set, then io_uring guarantees that both sync and async
+execution of a request assumes the credentials of the task that called
+.I
+io_uring_enter(2)
+to queue the requests. If this flag isn't set, then requests are issued with
+the credentials of the task that originally registered the io_uring. If only
+one task is using a ring, then this flag doesn't matter as the credentials
+will always be the same. Note that this is the default behavior, tasks can
+still register different personalities through
+.I
+io_uring_register(2)
+with
+.B IORING_REGISTER_PERSONALITY
+and specify the personality to use in the sqe.
+.TP
+.B IORING_FEAT_FAST_POLL
+If this flag is set, then io_uring supports using an internal poll mechanism
+to drive data/space readiness. This means that requests that cannot read or
+write data to a file no longer need to be punted to an async thread for
+handling, instead they will begin operation when the file is ready. This is
+similar to doing poll + read/write in userspace, but eliminates the need to do
+so. If this flag is set, requests waiting on space/data consume a lot less
+resources doing so as they are not blocking a thread.
+.TP
+.B IORING_FEAT_POLL_32BITS
+If this flag is set, the
+.B IORING_OP_POLL_ADD
+command accepts the full 32-bit range of epoll based flags. Most notably
+.B EPOLLEXCLUSIVE
+which allows exclusive (waking single waiters) behavior.
+.TP
+.B IORING_FEAT_SQPOLL_NONFIXED
+If this flag is set, the
+.B IORING_SETUP_SQPOLL
+feature no longer requires the use of fixed files. Any normal file descriptor
+can be used for IO commands without needing registration.
+
+.PP
+The rest of the fields in the
+.I struct io_uring_params
+are filled in by the kernel, and provide the information necessary to
+memory map the submission queue, completion queue, and the array of
+submission queue entries.
+.I sq_entries
+specifies the number of submission queue entries allocated.
+.I sq_off
+describes the offsets of various ring buffer fields:
+.PP
+.in +4n
+.EX
+struct io_sqring_offsets {
+    __u32 head;
+    __u32 tail;
+    __u32 ring_mask;
+    __u32 ring_entries;
+    __u32 flags;
+    __u32 dropped;
+    __u32 array;
+    __u32 resv[3];
+};
+.EE
+.in
+.PP
+Taken together,
+.I sq_entries
+and
+.I sq_off
+provide all of the information necessary for accessing the submission
+queue ring buffer and the submission queue entry array.  The
+submission queue can be mapped with a call like:
+.PP
+.in +4n
+.EX
+ptr = mmap(0, sq_off.array + sq_entries * sizeof(__u32),
+           PROT_READ|PROT_WRITE, MAP_SHARED|MAP_POPULATE,
+           ring_fd, IORING_OFF_SQ_RING);
+.EE
+.in
+.PP
+where
+.I sq_off
+is the
+.I io_sqring_offsets
+structure, and
+.I ring_fd
+is the file descriptor returned from
+.BR io_uring_setup (2).
+The addition of
+.I sq_off.array
+to the length of the region accounts for the fact that the ring
+located at the end of the data structure.  As an example, the ring
+buffer head pointer can be accessed by adding
+.I sq_off.head
+to the address returned from
+.BR mmap (2):
+.PP
+.in +4n
+.EX
+head = ptr + sq_off.head;
+.EE
+.in
+
+The
+.I flags
+field is used by the kernel to communicate state information to the
+application.  Currently, it is used to inform the application when a
+call to
+.BR io_uring_enter (2)
+is necessary.  See the documentation for the
+.B IORING_SETUP_SQPOLL
+flag above.
+The
+.I dropped
+member is incremented for each invalid submission queue entry
+encountered in the ring buffer.
+
+The head and tail track the ring buffer state.  The tail is
+incremented by the application when submitting new I/O, and the head
+is incremented by the kernel when the I/O has been successfully
+submitted.  Determining the index of the head or tail into the ring is
+accomplished by applying a mask:
+.PP
+.in +4n
+.EX
+index = tail & ring_mask;
+.EE
+.in
+.PP
+The array of submission queue entries is mapped with:
+.PP
+.in +4n
+.EX
+sqentries = mmap(0, sq_entries * sizeof(struct io_uring_sqe),
+                 PROT_READ|PROT_WRITE, MAP_SHARED|MAP_POPULATE,
+                 ring_fd, IORING_OFF_SQES);
+.EE
+.in
+.PP
+The completion queue is described by
+.I cq_entries
+and
+.I cq_off
+shown here:
+.PP
+.in +4n
+.EX
+struct io_cqring_offsets {
+    __u32 head;
+    __u32 tail;
+    __u32 ring_mask;
+    __u32 ring_entries;
+    __u32 overflow;
+    __u32 cqes;
+    __u32 flags;
+    __u32 resv[3];
+};
+.EE
+.in
+.PP
+The completion queue is simpler, since the entries are not separated
+from the queue itself, and can be mapped with:
+.PP
+.in +4n
+.EX
+ptr = mmap(0, cq_off.cqes + cq_entries * sizeof(struct io_uring_cqe),
+           PROT_READ|PROT_WRITE, MAP_SHARED|MAP_POPULATE, ring_fd,
+           IORING_OFF_CQ_RING);
+.EE
+.in
+.PP
+Closing the file descriptor returned by
+.BR io_uring_setup (2)
+will free all resources associated with the io_uring context.
+.PP
+.SH RETURN VALUE
+.BR io_uring_setup (2)
+returns a new file descriptor on success.  The application may then
+provide the file descriptor in a subsequent
+.BR mmap (2)
+call to map the submission and completion queues, or to the
+.BR io_uring_register (2)
+or
+.BR io_uring_enter (2)
+system calls.
+
+On error, -1 is returned and
+.I errno
+is set appropriately.
+.PP
+.SH ERRORS
+.TP
+.B EFAULT
+params is outside your accessible address space.
+.TP
+.B EINVAL
+The resv array contains non-zero data, p.flags contains an unsupported
+flag,
+.I entries
+is out of bounds,
+.B IORING_SETUP_SQ_AFF
+was specified, but
+.B IORING_SETUP_SQPOLL
+was not, or
+.B IORING_SETUP_CQSIZE
+was specified, but
+.I io_uring_params.cq_entries
+was invalid.
+.TP
+.B EMFILE
+The per-process limit on the number of open file descriptors has been
+reached (see the description of
+.B RLIMIT_NOFILE
+in
+.BR getrlimit (2)).
+.TP
+.B ENFILE
+The system-wide limit on the total number of open files has been
+reached.
+.TP
+.B ENOMEM
+Insufficient kernel resources are available.
+.TP
+.B EPERM
+.B IORING_SETUP_SQPOLL
+was specified, but the effective user ID of the caller did not have sufficient
+privileges.
+.SH SEE ALSO
+.BR io_uring_register (2),
+.BR io_uring_enter (2)
diff --git a/src/Makefile b/src/Makefile
new file mode 100644
index 0000000..dfca826
--- /dev/null
+++ b/src/Makefile
@@ -0,0 +1,74 @@
+prefix ?= /usr
+includedir ?= $(prefix)/include
+libdir ?= $(prefix)/lib
+libdevdir ?= $(prefix)/lib
+
+CPPFLAGS ?=
+override CPPFLAGS += -Iinclude/ -include ../config-host.h
+CFLAGS ?= -g -fomit-frame-pointer -O2
+override CFLAGS += -Wall -Wextra -Wno-unused-parameter -Wno-sign-compare
+SO_CFLAGS=-fPIC $(CFLAGS)
+L_CFLAGS=$(CFLAGS)
+LINK_FLAGS=
+LINK_FLAGS+=$(LDFLAGS)
+ENABLE_SHARED ?= 1
+
+soname=liburing.so.2
+minor=0
+micro=0
+libname=$(soname).$(minor).$(micro)
+all_targets += liburing.a
+
+ifeq ($(ENABLE_SHARED),1)
+all_targets += $(libname)
+endif
+
+include ../Makefile.quiet
+
+ifneq ($(MAKECMDGOALS),clean)
+include ../config-host.mak
+endif
+
+all: $(all_targets)
+
+liburing_srcs := setup.c queue.c syscall.c register.c
+
+liburing_objs := $(patsubst %.c,%.ol,$(liburing_srcs))
+liburing_sobjs := $(patsubst %.c,%.os,$(liburing_srcs))
+
+$(liburing_objs) $(liburing_sobjs): include/liburing/io_uring.h
+
+%.os: %.c
+	$(QUIET_CC)$(CC) $(CPPFLAGS) $(SO_CFLAGS) -c -o $@ $<
+
+%.ol: %.c
+	$(QUIET_CC)$(CC) $(CPPFLAGS) $(L_CFLAGS) -c -o $@ $<
+
+AR ?= ar
+RANLIB ?= ranlib
+liburing.a: $(liburing_objs)
+	@rm -f liburing.a
+	$(QUIET_AR)$(AR) r liburing.a $^
+	$(QUIET_RANLIB)$(RANLIB) liburing.a
+
+$(libname): $(liburing_sobjs) liburing.map
+	$(QUIET_CC)$(CC) $(SO_CFLAGS) -shared -Wl,--version-script=liburing.map -Wl,-soname=$(soname) -o $@ $(liburing_sobjs) $(LINK_FLAGS)
+
+install: $(all_targets)
+	install -D -m 644 include/liburing/io_uring.h $(includedir)/liburing/io_uring.h
+	install -D -m 644 include/liburing.h $(includedir)/liburing.h
+	install -D -m 644 include/liburing/compat.h $(includedir)/liburing/compat.h
+	install -D -m 644 include/liburing/barrier.h $(includedir)/liburing/barrier.h
+	install -D -m 644 liburing.a $(libdevdir)/liburing.a
+ifeq ($(ENABLE_SHARED),1)
+	install -D -m 755 $(libname) $(libdir)/$(libname)
+	ln -sf $(libname) $(libdir)/$(soname)
+	ln -sf $(relativelibdir)$(libname) $(libdevdir)/liburing.so
+endif
+
+$(liburing_objs): include/liburing.h
+
+clean:
+	@rm -f $(all_targets) $(liburing_objs) $(liburing_sobjs) $(soname).new
+	@rm -f *.so* *.a *.o
+	@rm -f include/liburing/compat.h
diff --git a/src/include/liburing.h b/src/include/liburing.h
new file mode 100644
index 0000000..51dc602
--- /dev/null
+++ b/src/include/liburing.h
@@ -0,0 +1,700 @@
+/* SPDX-License-Identifier: MIT */
+#ifndef LIB_URING_H
+#define LIB_URING_H
+
+#ifndef _XOPEN_SOURCE
+#define _XOPEN_SOURCE 500 /* Required for glibc to expose sigset_t */
+#endif
+
+#include <sys/socket.h>
+#include <sys/uio.h>
+#include <sys/stat.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <inttypes.h>
+#include <time.h>
+#include <linux/swab.h>
+#include "liburing/compat.h"
+#include "liburing/io_uring.h"
+#include "liburing/barrier.h"
+
+#ifndef uring_unlikely
+#  define uring_unlikely(cond)      __builtin_expect(!!(cond), 0)
+#endif
+
+#ifndef uring_likely
+#  define uring_likely(cond)        __builtin_expect(!!(cond), 1)
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * Library interface to io_uring
+ */
+struct io_uring_sq {
+	unsigned *khead;
+	unsigned *ktail;
+	unsigned *kring_mask;
+	unsigned *kring_entries;
+	unsigned *kflags;
+	unsigned *kdropped;
+	unsigned *array;
+	struct io_uring_sqe *sqes;
+
+	unsigned sqe_head;
+	unsigned sqe_tail;
+
+	size_t ring_sz;
+	void *ring_ptr;
+
+	unsigned pad[4];
+};
+
+struct io_uring_cq {
+	unsigned *khead;
+	unsigned *ktail;
+	unsigned *kring_mask;
+	unsigned *kring_entries;
+	unsigned *kflags;
+	unsigned *koverflow;
+	struct io_uring_cqe *cqes;
+
+	size_t ring_sz;
+	void *ring_ptr;
+
+	unsigned pad[4];
+};
+
+struct io_uring {
+	struct io_uring_sq sq;
+	struct io_uring_cq cq;
+	unsigned flags;
+	int ring_fd;
+
+	unsigned features;
+	unsigned pad[3];
+};
+
+/*
+ * Library interface
+ */
+
+/*
+ * return an allocated io_uring_probe structure, or NULL if probe fails (for
+ * example, if it is not available). The caller is responsible for freeing it
+ */
+extern struct io_uring_probe *io_uring_get_probe_ring(struct io_uring *ring);
+/* same as io_uring_get_probe_ring, but takes care of ring init and teardown */
+extern struct io_uring_probe *io_uring_get_probe(void);
+
+/*
+ * frees a probe allocated through io_uring_get_probe() or
+ * io_uring_get_probe_ring()
+ */
+extern void io_uring_free_probe(struct io_uring_probe *probe);
+
+static inline int io_uring_opcode_supported(const struct io_uring_probe *p, int op)
+{
+	if (op > p->last_op)
+		return 0;
+	return (p->ops[op].flags & IO_URING_OP_SUPPORTED) != 0;
+}
+
+extern int io_uring_queue_init_params(unsigned entries, struct io_uring *ring,
+	struct io_uring_params *p);
+extern int io_uring_queue_init(unsigned entries, struct io_uring *ring,
+	unsigned flags);
+extern int io_uring_queue_mmap(int fd, struct io_uring_params *p,
+	struct io_uring *ring);
+extern int io_uring_ring_dontfork(struct io_uring *ring);
+extern void io_uring_queue_exit(struct io_uring *ring);
+unsigned io_uring_peek_batch_cqe(struct io_uring *ring,
+	struct io_uring_cqe **cqes, unsigned count);
+extern int io_uring_wait_cqes(struct io_uring *ring,
+	struct io_uring_cqe **cqe_ptr, unsigned wait_nr,
+	struct __kernel_timespec *ts, sigset_t *sigmask);
+extern int io_uring_wait_cqe_timeout(struct io_uring *ring,
+	struct io_uring_cqe **cqe_ptr, struct __kernel_timespec *ts);
+extern int io_uring_submit(struct io_uring *ring);
+extern int io_uring_submit_and_wait(struct io_uring *ring, unsigned wait_nr);
+extern struct io_uring_sqe *io_uring_get_sqe(struct io_uring *ring);
+
+extern int io_uring_register_buffers(struct io_uring *ring,
+					const struct iovec *iovecs,
+					unsigned nr_iovecs);
+extern int io_uring_unregister_buffers(struct io_uring *ring);
+extern int io_uring_register_files(struct io_uring *ring, const int *files,
+					unsigned nr_files);
+extern int io_uring_unregister_files(struct io_uring *ring);
+extern int io_uring_register_files_update(struct io_uring *ring, unsigned off,
+					int *files, unsigned nr_files);
+extern int io_uring_register_eventfd(struct io_uring *ring, int fd);
+extern int io_uring_register_eventfd_async(struct io_uring *ring, int fd);
+extern int io_uring_unregister_eventfd(struct io_uring *ring);
+extern int io_uring_register_probe(struct io_uring *ring,
+					struct io_uring_probe *p, unsigned nr);
+extern int io_uring_register_personality(struct io_uring *ring);
+extern int io_uring_unregister_personality(struct io_uring *ring, int id);
+extern int io_uring_register_restrictions(struct io_uring *ring,
+					  struct io_uring_restriction *res,
+					  unsigned int nr_res);
+extern int io_uring_enable_rings(struct io_uring *ring);
+extern int __io_uring_sqring_wait(struct io_uring *ring);
+
+/*
+ * Helper for the peek/wait single cqe functions. Exported because of that,
+ * but probably shouldn't be used directly in an application.
+ */
+extern int __io_uring_get_cqe(struct io_uring *ring,
+			      struct io_uring_cqe **cqe_ptr, unsigned submit,
+			      unsigned wait_nr, sigset_t *sigmask);
+
+#define LIBURING_UDATA_TIMEOUT	((__u64) -1)
+
+#define io_uring_for_each_cqe(ring, head, cqe)				\
+	/*								\
+	 * io_uring_smp_load_acquire() enforces the order of tail	\
+	 * and CQE reads.						\
+	 */								\
+	for (head = *(ring)->cq.khead;					\
+	     (cqe = (head != io_uring_smp_load_acquire((ring)->cq.ktail) ? \
+		&(ring)->cq.cqes[head & (*(ring)->cq.kring_mask)] : NULL)); \
+	     head++)							\
+
+/*
+ * Must be called after io_uring_for_each_cqe()
+ */
+static inline void io_uring_cq_advance(struct io_uring *ring,
+				       unsigned nr)
+{
+	if (nr) {
+		struct io_uring_cq *cq = &ring->cq;
+
+		/*
+		 * Ensure that the kernel only sees the new value of the head
+		 * index after the CQEs have been read.
+		 */
+		io_uring_smp_store_release(cq->khead, *cq->khead + nr);
+	}
+}
+
+/*
+ * Must be called after io_uring_{peek,wait}_cqe() after the cqe has
+ * been processed by the application.
+ */
+static inline void io_uring_cqe_seen(struct io_uring *ring,
+				     struct io_uring_cqe *cqe)
+{
+	if (cqe)
+		io_uring_cq_advance(ring, 1);
+}
+
+/*
+ * Command prep helpers
+ */
+static inline void io_uring_sqe_set_data(struct io_uring_sqe *sqe, void *data)
+{
+	sqe->user_data = (unsigned long) data;
+}
+
+static inline void *io_uring_cqe_get_data(const struct io_uring_cqe *cqe)
+{
+	return (void *) (uintptr_t) cqe->user_data;
+}
+
+static inline void io_uring_sqe_set_flags(struct io_uring_sqe *sqe,
+					  unsigned flags)
+{
+	sqe->flags = flags;
+}
+
+static inline void io_uring_prep_rw(int op, struct io_uring_sqe *sqe, int fd,
+				    const void *addr, unsigned len,
+				    __u64 offset)
+{
+	sqe->opcode = op;
+	sqe->flags = 0;
+	sqe->ioprio = 0;
+	sqe->fd = fd;
+	sqe->off = offset;
+	sqe->addr = (unsigned long) addr;
+	sqe->len = len;
+	sqe->rw_flags = 0;
+	sqe->user_data = 0;
+	sqe->__pad2[0] = sqe->__pad2[1] = sqe->__pad2[2] = 0;
+}
+
+/**
+ * @pre Either fd_in or fd_out must be a pipe.
+ * @param off_in If fd_in refers to a pipe, off_in must be (int64_t) -1;
+ *               If fd_in does not refer to a pipe and off_in is (int64_t) -1, then bytes are read
+ *               from fd_in starting from the file offset and it is adjust appropriately;
+ *               If fd_in does not refer to a pipe and off_in is not (int64_t) -1, then the
+ *               starting offset of fd_in will be off_in.
+ * @param off_out The description of off_in also applied to off_out.
+ * @param splice_flags see man splice(2) for description of flags.
+ *
+ * This splice operation can be used to implement sendfile by splicing to an intermediate pipe
+ * first, then splice to the final destination.
+ * In fact, the implementation of sendfile in kernel uses splice internally.
+ *
+ * NOTE that even if fd_in or fd_out refers to a pipe, the splice operation can still failed with
+ * EINVAL if one of the fd doesn't explicitly support splice operation, e.g. reading from terminal
+ * is unsupported from kernel 5.7 to 5.11.
+ * Check issue #291 for more information.
+ */
+static inline void io_uring_prep_splice(struct io_uring_sqe *sqe,
+					int fd_in, int64_t off_in,
+					int fd_out, int64_t off_out,
+					unsigned int nbytes,
+					unsigned int splice_flags)
+{
+	io_uring_prep_rw(IORING_OP_SPLICE, sqe, fd_out, NULL, nbytes, off_out);
+	sqe->splice_off_in = off_in;
+	sqe->splice_fd_in = fd_in;
+	sqe->splice_flags = splice_flags;
+}
+
+static inline void io_uring_prep_tee(struct io_uring_sqe *sqe,
+				     int fd_in, int fd_out,
+				     unsigned int nbytes,
+				     unsigned int splice_flags)
+{
+	io_uring_prep_rw(IORING_OP_TEE, sqe, fd_out, NULL, nbytes, 0);
+	sqe->splice_off_in = 0;
+	sqe->splice_fd_in = fd_in;
+	sqe->splice_flags = splice_flags;
+}
+
+static inline void io_uring_prep_readv(struct io_uring_sqe *sqe, int fd,
+				       const struct iovec *iovecs,
+				       unsigned nr_vecs, off_t offset)
+{
+	io_uring_prep_rw(IORING_OP_READV, sqe, fd, iovecs, nr_vecs, offset);
+}
+
+static inline void io_uring_prep_read_fixed(struct io_uring_sqe *sqe, int fd,
+					    void *buf, unsigned nbytes,
+					    off_t offset, int buf_index)
+{
+	io_uring_prep_rw(IORING_OP_READ_FIXED, sqe, fd, buf, nbytes, offset);
+	sqe->buf_index = buf_index;
+}
+
+static inline void io_uring_prep_writev(struct io_uring_sqe *sqe, int fd,
+					const struct iovec *iovecs,
+					unsigned nr_vecs, off_t offset)
+{
+	io_uring_prep_rw(IORING_OP_WRITEV, sqe, fd, iovecs, nr_vecs, offset);
+}
+
+static inline void io_uring_prep_write_fixed(struct io_uring_sqe *sqe, int fd,
+					     const void *buf, unsigned nbytes,
+					     off_t offset, int buf_index)
+{
+	io_uring_prep_rw(IORING_OP_WRITE_FIXED, sqe, fd, buf, nbytes, offset);
+	sqe->buf_index = buf_index;
+}
+
+static inline void io_uring_prep_recvmsg(struct io_uring_sqe *sqe, int fd,
+					 struct msghdr *msg, unsigned flags)
+{
+	io_uring_prep_rw(IORING_OP_RECVMSG, sqe, fd, msg, 1, 0);
+	sqe->msg_flags = flags;
+}
+
+static inline void io_uring_prep_sendmsg(struct io_uring_sqe *sqe, int fd,
+					 const struct msghdr *msg, unsigned flags)
+{
+	io_uring_prep_rw(IORING_OP_SENDMSG, sqe, fd, msg, 1, 0);
+	sqe->msg_flags = flags;
+}
+
+static inline void io_uring_prep_poll_add(struct io_uring_sqe *sqe, int fd,
+					  unsigned poll_mask)
+{
+	io_uring_prep_rw(IORING_OP_POLL_ADD, sqe, fd, NULL, 0, 0);
+#if __BYTE_ORDER == __BIG_ENDIAN
+	poll_mask = __swahw32(poll_mask);
+#endif
+	sqe->poll32_events = poll_mask;
+}
+
+static inline void io_uring_prep_poll_remove(struct io_uring_sqe *sqe,
+					     void *user_data)
+{
+	io_uring_prep_rw(IORING_OP_POLL_REMOVE, sqe, -1, user_data, 0, 0);
+}
+
+static inline void io_uring_prep_poll_update(struct io_uring_sqe *sqe,
+					     void *old_user_data,
+					     void *new_user_data,
+					     unsigned poll_mask, unsigned flags)
+{
+	io_uring_prep_rw(IORING_OP_POLL_REMOVE, sqe, -1, old_user_data, flags,
+			 (__u64)new_user_data);
+#if __BYTE_ORDER == __BIG_ENDIAN
+	poll_mask = __swahw32(poll_mask);
+#endif
+	sqe->poll32_events = poll_mask;
+}
+
+static inline void io_uring_prep_fsync(struct io_uring_sqe *sqe, int fd,
+				       unsigned fsync_flags)
+{
+	io_uring_prep_rw(IORING_OP_FSYNC, sqe, fd, NULL, 0, 0);
+	sqe->fsync_flags = fsync_flags;
+}
+
+static inline void io_uring_prep_nop(struct io_uring_sqe *sqe)
+{
+	io_uring_prep_rw(IORING_OP_NOP, sqe, -1, NULL, 0, 0);
+}
+
+static inline void io_uring_prep_timeout(struct io_uring_sqe *sqe,
+					 struct __kernel_timespec *ts,
+					 unsigned count, unsigned flags)
+{
+	io_uring_prep_rw(IORING_OP_TIMEOUT, sqe, -1, ts, 1, count);
+	sqe->timeout_flags = flags;
+}
+
+static inline void io_uring_prep_timeout_remove(struct io_uring_sqe *sqe,
+						__u64 user_data, unsigned flags)
+{
+	io_uring_prep_rw(IORING_OP_TIMEOUT_REMOVE, sqe, -1,
+				(void *)(unsigned long)user_data, 0, 0);
+	sqe->timeout_flags = flags;
+}
+
+static inline void io_uring_prep_timeout_update(struct io_uring_sqe *sqe,
+						struct __kernel_timespec *ts,
+						__u64 user_data, unsigned flags)
+{
+	io_uring_prep_rw(IORING_OP_TIMEOUT_REMOVE, sqe, -1,
+				(void *)(unsigned long)user_data, 0,
+				(uintptr_t)ts);
+	sqe->timeout_flags = flags | IORING_TIMEOUT_UPDATE;
+}
+
+static inline void io_uring_prep_accept(struct io_uring_sqe *sqe, int fd,
+					struct sockaddr *addr,
+					socklen_t *addrlen, int flags)
+{
+	io_uring_prep_rw(IORING_OP_ACCEPT, sqe, fd, addr, 0,
+				(__u64) (unsigned long) addrlen);
+	sqe->accept_flags = flags;
+}
+
+static inline void io_uring_prep_cancel(struct io_uring_sqe *sqe, void *user_data,
+					int flags)
+{
+	io_uring_prep_rw(IORING_OP_ASYNC_CANCEL, sqe, -1, user_data, 0, 0);
+	sqe->cancel_flags = flags;
+}
+
+static inline void io_uring_prep_link_timeout(struct io_uring_sqe *sqe,
+					      struct __kernel_timespec *ts,
+					      unsigned flags)
+{
+	io_uring_prep_rw(IORING_OP_LINK_TIMEOUT, sqe, -1, ts, 1, 0);
+	sqe->timeout_flags = flags;
+}
+
+static inline void io_uring_prep_connect(struct io_uring_sqe *sqe, int fd,
+					 const struct sockaddr *addr,
+					 socklen_t addrlen)
+{
+	io_uring_prep_rw(IORING_OP_CONNECT, sqe, fd, addr, 0, addrlen);
+}
+
+static inline void io_uring_prep_files_update(struct io_uring_sqe *sqe,
+					      int *fds, unsigned nr_fds,
+					      int offset)
+{
+	io_uring_prep_rw(IORING_OP_FILES_UPDATE, sqe, -1, fds, nr_fds, offset);
+}
+
+static inline void io_uring_prep_fallocate(struct io_uring_sqe *sqe, int fd,
+					   int mode, off_t offset, off_t len)
+{
+
+	io_uring_prep_rw(IORING_OP_FALLOCATE, sqe, fd,
+			(const uintptr_t *) (unsigned long) len, mode, offset);
+}
+
+static inline void io_uring_prep_openat(struct io_uring_sqe *sqe, int dfd,
+					const char *path, int flags, mode_t mode)
+{
+	io_uring_prep_rw(IORING_OP_OPENAT, sqe, dfd, path, mode, 0);
+	sqe->open_flags = flags;
+}
+
+static inline void io_uring_prep_close(struct io_uring_sqe *sqe, int fd)
+{
+	io_uring_prep_rw(IORING_OP_CLOSE, sqe, fd, NULL, 0, 0);
+}
+
+static inline void io_uring_prep_read(struct io_uring_sqe *sqe, int fd,
+				      void *buf, unsigned nbytes, off_t offset)
+{
+	io_uring_prep_rw(IORING_OP_READ, sqe, fd, buf, nbytes, offset);
+}
+
+static inline void io_uring_prep_write(struct io_uring_sqe *sqe, int fd,
+				       const void *buf, unsigned nbytes, off_t offset)
+{
+	io_uring_prep_rw(IORING_OP_WRITE, sqe, fd, buf, nbytes, offset);
+}
+
+struct statx;
+static inline void io_uring_prep_statx(struct io_uring_sqe *sqe, int dfd,
+				const char *path, int flags, unsigned mask,
+				struct statx *statxbuf)
+{
+	io_uring_prep_rw(IORING_OP_STATX, sqe, dfd, path, mask,
+				(__u64) (unsigned long) statxbuf);
+	sqe->statx_flags = flags;
+}
+
+static inline void io_uring_prep_fadvise(struct io_uring_sqe *sqe, int fd,
+					 off_t offset, off_t len, int advice)
+{
+	io_uring_prep_rw(IORING_OP_FADVISE, sqe, fd, NULL, len, offset);
+	sqe->fadvise_advice = advice;
+}
+
+static inline void io_uring_prep_madvise(struct io_uring_sqe *sqe, void *addr,
+					 off_t length, int advice)
+{
+	io_uring_prep_rw(IORING_OP_MADVISE, sqe, -1, addr, length, 0);
+	sqe->fadvise_advice = advice;
+}
+
+static inline void io_uring_prep_send(struct io_uring_sqe *sqe, int sockfd,
+				      const void *buf, size_t len, int flags)
+{
+	io_uring_prep_rw(IORING_OP_SEND, sqe, sockfd, buf, len, 0);
+	sqe->msg_flags = flags;
+}
+
+static inline void io_uring_prep_recv(struct io_uring_sqe *sqe, int sockfd,
+				      void *buf, size_t len, int flags)
+{
+	io_uring_prep_rw(IORING_OP_RECV, sqe, sockfd, buf, len, 0);
+	sqe->msg_flags = flags;
+}
+
+static inline void io_uring_prep_openat2(struct io_uring_sqe *sqe, int dfd,
+					const char *path, struct open_how *how)
+{
+	io_uring_prep_rw(IORING_OP_OPENAT2, sqe, dfd, path, sizeof(*how),
+				(uint64_t) (uintptr_t) how);
+}
+
+struct epoll_event;
+static inline void io_uring_prep_epoll_ctl(struct io_uring_sqe *sqe, int epfd,
+					   int fd, int op,
+					   struct epoll_event *ev)
+{
+	io_uring_prep_rw(IORING_OP_EPOLL_CTL, sqe, epfd, ev, op, fd);
+}
+
+static inline void io_uring_prep_provide_buffers(struct io_uring_sqe *sqe,
+						 void *addr, int len, int nr,
+						 int bgid, int bid)
+{
+	io_uring_prep_rw(IORING_OP_PROVIDE_BUFFERS, sqe, nr, addr, len, bid);
+	sqe->buf_group = bgid;
+}
+
+static inline void io_uring_prep_remove_buffers(struct io_uring_sqe *sqe,
+						int nr, int bgid)
+{
+	io_uring_prep_rw(IORING_OP_REMOVE_BUFFERS, sqe, nr, NULL, 0, 0);
+	sqe->buf_group = bgid;
+}
+
+static inline void io_uring_prep_shutdown(struct io_uring_sqe *sqe, int fd,
+					  int how)
+{
+	io_uring_prep_rw(IORING_OP_SHUTDOWN, sqe, fd, NULL, how, 0);
+}
+
+static inline void io_uring_prep_unlinkat(struct io_uring_sqe *sqe, int dfd,
+					  const char *path, int flags)
+{
+	io_uring_prep_rw(IORING_OP_UNLINKAT, sqe, dfd, path, 0, 0);
+	sqe->unlink_flags = flags;
+}
+
+static inline void io_uring_prep_renameat(struct io_uring_sqe *sqe, int olddfd,
+					  const char *oldpath, int newdfd,
+					  const char *newpath, int flags)
+{
+	io_uring_prep_rw(IORING_OP_RENAMEAT, sqe, olddfd, oldpath, newdfd,
+				(uint64_t) (uintptr_t) newpath);
+	sqe->rename_flags = flags;
+}
+
+static inline void io_uring_prep_sync_file_range(struct io_uring_sqe *sqe,
+						 int fd, unsigned len,
+						 off_t offset, int flags)
+{
+	io_uring_prep_rw(IORING_OP_SYNC_FILE_RANGE, sqe, fd, NULL, len, offset);
+	sqe->sync_range_flags = flags;
+}
+
+static inline void io_uring_prep_mkdirat(struct io_uring_sqe *sqe, int dfd,
+					const char *path, mode_t mode)
+{
+	io_uring_prep_rw(IORING_OP_MKDIRAT, sqe, dfd, path, mode, 0);
+}
+
+static inline void io_uring_prep_symlinkat(struct io_uring_sqe *sqe,
+					const char *target, int newdirfd, const char *linkpath)
+{
+	io_uring_prep_rw(IORING_OP_SYMLINKAT, sqe, newdirfd, target, 0,
+				(uint64_t) (uintptr_t) linkpath);
+}
+
+static inline void io_uring_prep_linkat(struct io_uring_sqe *sqe, int olddfd,
+					const char *oldpath, int newdfd,
+					const char *newpath, int flags)
+{
+	io_uring_prep_rw(IORING_OP_LINKAT, sqe, olddfd, oldpath, newdfd,
+				(uint64_t) (uintptr_t) newpath);
+	sqe->hardlink_flags = flags;
+}
+
+/*
+ * Returns number of unconsumed (if SQPOLL) or unsubmitted entries exist in
+ * the SQ ring
+ */
+static inline unsigned io_uring_sq_ready(const struct io_uring *ring)
+{
+	/*
+	 * Without a barrier, we could miss an update and think the SQ wasn't ready.
+	 * We don't need the load acquire for non-SQPOLL since then we drive updates.
+	 */
+	if (ring->flags & IORING_SETUP_SQPOLL)
+		return ring->sq.sqe_tail - io_uring_smp_load_acquire(ring->sq.khead);
+
+	/* always use real head, to avoid losing sync for short submit */
+	return ring->sq.sqe_tail - *ring->sq.khead;
+}
+
+/*
+ * Returns how much space is left in the SQ ring.
+ */
+static inline unsigned io_uring_sq_space_left(const struct io_uring *ring)
+{
+	return *ring->sq.kring_entries - io_uring_sq_ready(ring);
+}
+
+/*
+ * Only applicable when using SQPOLL - allows the caller to wait for space
+ * to free up in the SQ ring, which happens when the kernel side thread has
+ * consumed one or more entries. If the SQ ring is currently non-full, no
+ * action is taken. Note: may return -EINVAL if the kernel doesn't support
+ * this feature.
+ */
+static inline int io_uring_sqring_wait(struct io_uring *ring)
+{
+	if (!(ring->flags & IORING_SETUP_SQPOLL))
+		return 0;
+	if (io_uring_sq_space_left(ring))
+		return 0;
+
+	return __io_uring_sqring_wait(ring);
+}
+
+/*
+ * Returns how many unconsumed entries are ready in the CQ ring
+ */
+static inline unsigned io_uring_cq_ready(const struct io_uring *ring)
+{
+	return io_uring_smp_load_acquire(ring->cq.ktail) - *ring->cq.khead;
+}
+
+/*
+ * Returns true if the eventfd notification is currently enabled
+ */
+static inline bool io_uring_cq_eventfd_enabled(const struct io_uring *ring)
+{
+	if (!ring->cq.kflags)
+		return true;
+
+	return !(*ring->cq.kflags & IORING_CQ_EVENTFD_DISABLED);
+}
+
+/*
+ * Toggle eventfd notification on or off, if an eventfd is registered with
+ * the ring.
+ */
+static inline int io_uring_cq_eventfd_toggle(struct io_uring *ring,
+					     bool enabled)
+{
+	uint32_t flags;
+
+	if (!!enabled == io_uring_cq_eventfd_enabled(ring))
+		return 0;
+
+	if (!ring->cq.kflags)
+		return -EOPNOTSUPP;
+
+	flags = *ring->cq.kflags;
+
+	if (enabled)
+		flags &= ~IORING_CQ_EVENTFD_DISABLED;
+	else
+		flags |= IORING_CQ_EVENTFD_DISABLED;
+
+	IO_URING_WRITE_ONCE(*ring->cq.kflags, flags);
+
+	return 0;
+}
+
+/*
+ * Return an IO completion, waiting for 'wait_nr' completions if one isn't
+ * readily available. Returns 0 with cqe_ptr filled in on success, -errno on
+ * failure.
+ */
+static inline int io_uring_wait_cqe_nr(struct io_uring *ring,
+				      struct io_uring_cqe **cqe_ptr,
+				      unsigned wait_nr)
+{
+	return __io_uring_get_cqe(ring, cqe_ptr, 0, wait_nr, NULL);
+}
+
+/*
+ * Return an IO completion, if one is readily available. Returns 0 with
+ * cqe_ptr filled in on success, -errno on failure.
+ */
+static inline int io_uring_peek_cqe(struct io_uring *ring,
+				    struct io_uring_cqe **cqe_ptr)
+{
+	return io_uring_wait_cqe_nr(ring, cqe_ptr, 0);
+}
+
+/*
+ * Return an IO completion, waiting for it if necessary. Returns 0 with
+ * cqe_ptr filled in on success, -errno on failure.
+ */
+static inline int io_uring_wait_cqe(struct io_uring *ring,
+				    struct io_uring_cqe **cqe_ptr)
+{
+	return io_uring_wait_cqe_nr(ring, cqe_ptr, 1);
+}
+
+ssize_t io_uring_mlock_size(unsigned entries, unsigned flags);
+ssize_t io_uring_mlock_size_params(unsigned entries, struct io_uring_params *p);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/src/include/liburing/barrier.h b/src/include/liburing/barrier.h
new file mode 100644
index 0000000..89ac682
--- /dev/null
+++ b/src/include/liburing/barrier.h
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: MIT */
+#ifndef LIBURING_BARRIER_H
+#define LIBURING_BARRIER_H
+
+/*
+From the kernel documentation file refcount-vs-atomic.rst:
+
+A RELEASE memory ordering guarantees that all prior loads and
+stores (all po-earlier instructions) on the same CPU are completed
+before the operation. It also guarantees that all po-earlier
+stores on the same CPU and all propagated stores from other CPUs
+must propagate to all other CPUs before the release operation
+(A-cumulative property). This is implemented using
+:c:func:`smp_store_release`.
+
+An ACQUIRE memory ordering guarantees that all post loads and
+stores (all po-later instructions) on the same CPU are
+completed after the acquire operation. It also guarantees that all
+po-later stores on the same CPU must propagate to all other CPUs
+after the acquire operation executes. This is implemented using
+:c:func:`smp_acquire__after_ctrl_dep`.
+*/
+
+#ifdef __cplusplus
+#include <atomic>
+
+template <typename T>
+static inline void IO_URING_WRITE_ONCE(T &var, T val)
+{
+	std::atomic_store_explicit(reinterpret_cast<std::atomic<T> *>(&var),
+				   val, std::memory_order_relaxed);
+}
+template <typename T>
+static inline T IO_URING_READ_ONCE(const T &var)
+{
+	return std::atomic_load_explicit(
+		reinterpret_cast<const std::atomic<T> *>(&var),
+		std::memory_order_relaxed);
+}
+
+template <typename T>
+static inline void io_uring_smp_store_release(T *p, T v)
+{
+	std::atomic_store_explicit(reinterpret_cast<std::atomic<T> *>(p), v,
+				   std::memory_order_release);
+}
+
+template <typename T>
+static inline T io_uring_smp_load_acquire(const T *p)
+{
+	return std::atomic_load_explicit(
+		reinterpret_cast<const std::atomic<T> *>(p),
+		std::memory_order_acquire);
+}
+#else
+#include <stdatomic.h>
+
+#define IO_URING_WRITE_ONCE(var, val)				\
+	atomic_store_explicit((_Atomic __typeof__(var) *)&(var),	\
+			      (val), memory_order_relaxed)
+#define IO_URING_READ_ONCE(var)					\
+	atomic_load_explicit((_Atomic __typeof__(var) *)&(var),	\
+			     memory_order_relaxed)
+
+#define io_uring_smp_store_release(p, v)			\
+	atomic_store_explicit((_Atomic __typeof__(*(p)) *)(p), (v), \
+			      memory_order_release)
+#define io_uring_smp_load_acquire(p)				\
+	atomic_load_explicit((_Atomic __typeof__(*(p)) *)(p),	\
+			     memory_order_acquire)
+#endif
+
+#endif /* defined(LIBURING_BARRIER_H) */
diff --git a/src/include/liburing/io_uring.h b/src/include/liburing/io_uring.h
new file mode 100644
index 0000000..e4a4fc4
--- /dev/null
+++ b/src/include/liburing/io_uring.h
@@ -0,0 +1,412 @@
+/* SPDX-License-Identifier: (GPL-2.0 WITH Linux-syscall-note) OR MIT */
+/*
+ * Header file for the io_uring interface.
+ *
+ * Copyright (C) 2019 Jens Axboe
+ * Copyright (C) 2019 Christoph Hellwig
+ */
+#ifndef LINUX_IO_URING_H
+#define LINUX_IO_URING_H
+
+#include <linux/fs.h>
+#include <linux/types.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * IO submission data structure (Submission Queue Entry)
+ */
+struct io_uring_sqe {
+	__u8	opcode;		/* type of operation for this sqe */
+	__u8	flags;		/* IOSQE_ flags */
+	__u16	ioprio;		/* ioprio for the request */
+	__s32	fd;		/* file descriptor to do IO on */
+	union {
+		__u64	off;	/* offset into file */
+		__u64	addr2;
+	};
+	union {
+		__u64	addr;	/* pointer to buffer or iovecs */
+		__u64	splice_off_in;
+	};
+	__u32	len;		/* buffer size or number of iovecs */
+	union {
+		__kernel_rwf_t	rw_flags;
+		__u32		fsync_flags;
+		__u16		poll_events;	/* compatibility */
+		__u32		poll32_events;	/* word-reversed for BE */
+		__u32		sync_range_flags;
+		__u32		msg_flags;
+		__u32		timeout_flags;
+		__u32		accept_flags;
+		__u32		cancel_flags;
+		__u32		open_flags;
+		__u32		statx_flags;
+		__u32		fadvise_advice;
+		__u32		splice_flags;
+		__u32		rename_flags;
+		__u32		unlink_flags;
+		__u32		hardlink_flags;
+	};
+	__u64	user_data;	/* data to be passed back at completion time */
+	union {
+		struct {
+			/* pack this to avoid bogus arm OABI complaints */
+			union {
+				/* index into fixed buffers, if used */
+				__u16	buf_index;
+				/* for grouped buffer selection */
+				__u16	buf_group;
+			} __attribute__((packed));
+			/* personality to use, if used */
+			__u16	personality;
+			__s32	splice_fd_in;
+		};
+		__u64	__pad2[3];
+	};
+};
+
+enum {
+	IOSQE_FIXED_FILE_BIT,
+	IOSQE_IO_DRAIN_BIT,
+	IOSQE_IO_LINK_BIT,
+	IOSQE_IO_HARDLINK_BIT,
+	IOSQE_ASYNC_BIT,
+	IOSQE_BUFFER_SELECT_BIT,
+};
+
+/*
+ * sqe->flags
+ */
+/* use fixed fileset */
+#define IOSQE_FIXED_FILE	(1U << IOSQE_FIXED_FILE_BIT)
+/* issue after inflight IO */
+#define IOSQE_IO_DRAIN		(1U << IOSQE_IO_DRAIN_BIT)
+/* links next sqe */
+#define IOSQE_IO_LINK		(1U << IOSQE_IO_LINK_BIT)
+/* like LINK, but stronger */
+#define IOSQE_IO_HARDLINK	(1U << IOSQE_IO_HARDLINK_BIT)
+/* always go async */
+#define IOSQE_ASYNC		(1U << IOSQE_ASYNC_BIT)
+/* select buffer from sqe->buf_group */
+#define IOSQE_BUFFER_SELECT	(1U << IOSQE_BUFFER_SELECT_BIT)
+
+/*
+ * io_uring_setup() flags
+ */
+#define IORING_SETUP_IOPOLL	(1U << 0)	/* io_context is polled */
+#define IORING_SETUP_SQPOLL	(1U << 1)	/* SQ poll thread */
+#define IORING_SETUP_SQ_AFF	(1U << 2)	/* sq_thread_cpu is valid */
+#define IORING_SETUP_CQSIZE	(1U << 3)	/* app defines CQ size */
+#define IORING_SETUP_CLAMP	(1U << 4)	/* clamp SQ/CQ ring sizes */
+#define IORING_SETUP_ATTACH_WQ	(1U << 5)	/* attach to existing wq */
+#define IORING_SETUP_R_DISABLED	(1U << 6)	/* start with ring disabled */
+
+enum {
+	IORING_OP_NOP,
+	IORING_OP_READV,
+	IORING_OP_WRITEV,
+	IORING_OP_FSYNC,
+	IORING_OP_READ_FIXED,
+	IORING_OP_WRITE_FIXED,
+	IORING_OP_POLL_ADD,
+	IORING_OP_POLL_REMOVE,
+	IORING_OP_SYNC_FILE_RANGE,
+	IORING_OP_SENDMSG,
+	IORING_OP_RECVMSG,
+	IORING_OP_TIMEOUT,
+	IORING_OP_TIMEOUT_REMOVE,
+	IORING_OP_ACCEPT,
+	IORING_OP_ASYNC_CANCEL,
+	IORING_OP_LINK_TIMEOUT,
+	IORING_OP_CONNECT,
+	IORING_OP_FALLOCATE,
+	IORING_OP_OPENAT,
+	IORING_OP_CLOSE,
+	IORING_OP_FILES_UPDATE,
+	IORING_OP_STATX,
+	IORING_OP_READ,
+	IORING_OP_WRITE,
+	IORING_OP_FADVISE,
+	IORING_OP_MADVISE,
+	IORING_OP_SEND,
+	IORING_OP_RECV,
+	IORING_OP_OPENAT2,
+	IORING_OP_EPOLL_CTL,
+	IORING_OP_SPLICE,
+	IORING_OP_PROVIDE_BUFFERS,
+	IORING_OP_REMOVE_BUFFERS,
+	IORING_OP_TEE,
+	IORING_OP_SHUTDOWN,
+	IORING_OP_RENAMEAT,
+	IORING_OP_UNLINKAT,
+	IORING_OP_MKDIRAT,
+	IORING_OP_SYMLINKAT,
+	IORING_OP_LINKAT,
+
+	/* this goes last, obviously */
+	IORING_OP_LAST,
+};
+
+/*
+ * sqe->fsync_flags
+ */
+#define IORING_FSYNC_DATASYNC	(1U << 0)
+
+/*
+ * sqe->timeout_flags
+ */
+#define IORING_TIMEOUT_ABS	(1U << 0)
+#define IORING_TIMEOUT_UPDATE	(1U << 1)
+
+/*
+ * sqe->splice_flags
+ * extends splice(2) flags
+ */
+#define SPLICE_F_FD_IN_FIXED	(1U << 31) /* the last bit of __u32 */
+
+/*
+ * POLL_ADD flags. Note that since sqe->poll_events is the flag space, the
+ * command flags for POLL_ADD are stored in sqe->len.
+ *
+ * IORING_POLL_ADD_MULTI	Multishot poll. Sets IORING_CQE_F_MORE if
+ *				the poll handler will continue to report
+ *				CQEs on behalf of the same SQE.
+ *
+ * IORING_POLL_UPDATE		Update existing poll request, matching
+ *				sqe->addr as the old user_data field.
+ */
+#define IORING_POLL_ADD_MULTI	(1U << 0)
+#define IORING_POLL_UPDATE_EVENTS	(1U << 1)
+#define IORING_POLL_UPDATE_USER_DATA	(1U << 2)
+
+/*
+ * IO completion data structure (Completion Queue Entry)
+ */
+struct io_uring_cqe {
+	__u64	user_data;	/* sqe->data submission passed back */
+	__s32	res;		/* result code for this event */
+	__u32	flags;
+};
+
+/*
+ * cqe->flags
+ *
+ * IORING_CQE_F_BUFFER	If set, the upper 16 bits are the buffer ID
+ * IORING_CQE_F_MORE	If set, parent SQE will generate more CQE entries
+ */
+#define IORING_CQE_F_BUFFER		(1U << 0)
+#define IORING_CQE_F_MORE		(1U << 1)
+
+enum {
+	IORING_CQE_BUFFER_SHIFT		= 16,
+};
+
+/*
+ * Magic offsets for the application to mmap the data it needs
+ */
+#define IORING_OFF_SQ_RING		0ULL
+#define IORING_OFF_CQ_RING		0x8000000ULL
+#define IORING_OFF_SQES			0x10000000ULL
+
+/*
+ * Filled with the offset for mmap(2)
+ */
+struct io_sqring_offsets {
+	__u32 head;
+	__u32 tail;
+	__u32 ring_mask;
+	__u32 ring_entries;
+	__u32 flags;
+	__u32 dropped;
+	__u32 array;
+	__u32 resv1;
+	__u64 resv2;
+};
+
+/*
+ * sq_ring->flags
+ */
+#define IORING_SQ_NEED_WAKEUP	(1U << 0) /* needs io_uring_enter wakeup */
+#define IORING_SQ_CQ_OVERFLOW	(1U << 1) /* CQ ring is overflown */
+
+struct io_cqring_offsets {
+	__u32 head;
+	__u32 tail;
+	__u32 ring_mask;
+	__u32 ring_entries;
+	__u32 overflow;
+	__u32 cqes;
+	__u32 flags;
+	__u32 resv1;
+	__u64 resv2;
+};
+
+/*
+ * cq_ring->flags
+ */
+
+/* disable eventfd notifications */
+#define IORING_CQ_EVENTFD_DISABLED	(1U << 0)
+
+/*
+ * io_uring_enter(2) flags
+ */
+#define IORING_ENTER_GETEVENTS	(1U << 0)
+#define IORING_ENTER_SQ_WAKEUP	(1U << 1)
+#define IORING_ENTER_SQ_WAIT	(1U << 2)
+#define IORING_ENTER_EXT_ARG	(1U << 3)
+
+/*
+ * Passed in for io_uring_setup(2). Copied back with updated info on success
+ */
+struct io_uring_params {
+	__u32 sq_entries;
+	__u32 cq_entries;
+	__u32 flags;
+	__u32 sq_thread_cpu;
+	__u32 sq_thread_idle;
+	__u32 features;
+	__u32 wq_fd;
+	__u32 resv[3];
+	struct io_sqring_offsets sq_off;
+	struct io_cqring_offsets cq_off;
+};
+
+/*
+ * io_uring_params->features flags
+ */
+#define IORING_FEAT_SINGLE_MMAP		(1U << 0)
+#define IORING_FEAT_NODROP		(1U << 1)
+#define IORING_FEAT_SUBMIT_STABLE	(1U << 2)
+#define IORING_FEAT_RW_CUR_POS		(1U << 3)
+#define IORING_FEAT_CUR_PERSONALITY	(1U << 4)
+#define IORING_FEAT_FAST_POLL		(1U << 5)
+#define IORING_FEAT_POLL_32BITS 	(1U << 6)
+#define IORING_FEAT_SQPOLL_NONFIXED	(1U << 7)
+#define IORING_FEAT_EXT_ARG		(1U << 8)
+#define IORING_FEAT_NATIVE_WORKERS	(1U << 9)
+#define IORING_FEAT_RSRC_TAGS		(1U << 10)
+
+/*
+ * io_uring_register(2) opcodes and arguments
+ */
+enum {
+	IORING_REGISTER_BUFFERS			= 0,
+	IORING_UNREGISTER_BUFFERS		= 1,
+	IORING_REGISTER_FILES			= 2,
+	IORING_UNREGISTER_FILES			= 3,
+	IORING_REGISTER_EVENTFD			= 4,
+	IORING_UNREGISTER_EVENTFD		= 5,
+	IORING_REGISTER_FILES_UPDATE		= 6,
+	IORING_REGISTER_EVENTFD_ASYNC		= 7,
+	IORING_REGISTER_PROBE			= 8,
+	IORING_REGISTER_PERSONALITY		= 9,
+	IORING_UNREGISTER_PERSONALITY		= 10,
+	IORING_REGISTER_RESTRICTIONS		= 11,
+	IORING_REGISTER_ENABLE_RINGS		= 12,
+
+	/* extended with tagging */
+	IORING_REGISTER_FILES2			= 13,
+	IORING_REGISTER_FILES_UPDATE2		= 14,
+	IORING_REGISTER_BUFFERS2		= 15,
+	IORING_REGISTER_BUFFERS_UPDATE		= 16,
+
+	/* this goes last */
+	IORING_REGISTER_LAST
+};
+
+/* deprecated, see struct io_uring_rsrc_update */
+struct io_uring_files_update {
+	__u32 offset;
+	__u32 resv;
+	__aligned_u64 /* __s32 * */ fds;
+};
+
+struct io_uring_rsrc_register {
+	__u32 nr;
+	__u32 resv;
+	__u64 resv2;
+	__aligned_u64 data;
+	__aligned_u64 tags;
+};
+
+struct io_uring_rsrc_update {
+	__u32 offset;
+	__u32 resv;
+	__aligned_u64 data;
+};
+
+struct io_uring_rsrc_update2 {
+	__u32 offset;
+	__u32 resv;
+	__aligned_u64 data;
+	__aligned_u64 tags;
+	__u32 nr;
+	__u32 resv2;
+};
+
+/* Skip updating fd indexes set to this value in the fd table */
+#define IORING_REGISTER_FILES_SKIP	(-2)
+
+#define IO_URING_OP_SUPPORTED	(1U << 0)
+
+struct io_uring_probe_op {
+	__u8 op;
+	__u8 resv;
+	__u16 flags;	/* IO_URING_OP_* flags */
+	__u32 resv2;
+};
+
+struct io_uring_probe {
+	__u8 last_op;	/* last opcode supported */
+	__u8 ops_len;	/* length of ops[] array below */
+	__u16 resv;
+	__u32 resv2[3];
+	struct io_uring_probe_op ops[];
+};
+
+struct io_uring_restriction {
+	__u16 opcode;
+	union {
+		__u8 register_op; /* IORING_RESTRICTION_REGISTER_OP */
+		__u8 sqe_op;      /* IORING_RESTRICTION_SQE_OP */
+		__u8 sqe_flags;   /* IORING_RESTRICTION_SQE_FLAGS_* */
+	};
+	__u8 resv;
+	__u32 resv2[3];
+};
+
+/*
+ * io_uring_restriction->opcode values
+ */
+enum {
+	/* Allow an io_uring_register(2) opcode */
+	IORING_RESTRICTION_REGISTER_OP		= 0,
+
+	/* Allow an sqe opcode */
+	IORING_RESTRICTION_SQE_OP		= 1,
+
+	/* Allow sqe flags */
+	IORING_RESTRICTION_SQE_FLAGS_ALLOWED	= 2,
+
+	/* Require sqe flags (these flags must be set on each submission) */
+	IORING_RESTRICTION_SQE_FLAGS_REQUIRED	= 3,
+
+	IORING_RESTRICTION_LAST
+};
+
+struct io_uring_getevents_arg {
+	__u64	sigmask;
+	__u32	sigmask_sz;
+	__u32	pad;
+	__u64	ts;
+};
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/src/liburing.map b/src/liburing.map
new file mode 100644
index 0000000..012ac4e
--- /dev/null
+++ b/src/liburing.map
@@ -0,0 +1,39 @@
+LIBURING_2.0 {
+	global:
+		io_uring_get_probe;
+		io_uring_get_probe_ring;
+		io_uring_free_probe;
+		io_uring_get_sqe;
+		io_uring_peek_batch_cqe;
+		io_uring_queue_exit;
+		io_uring_queue_init;
+		io_uring_queue_init_params;
+		io_uring_queue_mmap;
+		io_uring_register_buffers;
+		io_uring_register_eventfd;
+		io_uring_register_eventfd_async;
+		io_uring_register_files;
+		io_uring_register_files_update;
+		io_uring_register_personality;
+		io_uring_register_probe;
+		io_uring_ring_dontfork;
+		io_uring_submit;
+		io_uring_submit_and_wait;
+		io_uring_unregister_buffers;
+		io_uring_unregister_eventfd;
+		io_uring_unregister_files;
+		io_uring_unregister_personality;
+		io_uring_wait_cqe_timeout;
+		io_uring_wait_cqes;
+
+		__io_uring_get_cqe;
+		__io_uring_sqring_wait;
+	local:
+		*;
+};
+
+LIBURING_2.1 {
+	global:
+		io_uring_mlock_size_params;
+		io_uring_mlock_size;
+} LIBURING_2.0;
diff --git a/src/queue.c b/src/queue.c
new file mode 100644
index 0000000..2f0f19b
--- /dev/null
+++ b/src/queue.c
@@ -0,0 +1,404 @@
+/* SPDX-License-Identifier: MIT */
+#define _POSIX_C_SOURCE 200112L
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <stdbool.h>
+
+#include "liburing/compat.h"
+#include "liburing/io_uring.h"
+#include "liburing.h"
+#include "liburing/barrier.h"
+
+#include "syscall.h"
+
+/*
+ * Returns true if we're not using SQ thread (thus nobody submits but us)
+ * or if IORING_SQ_NEED_WAKEUP is set, so submit thread must be explicitly
+ * awakened. For the latter case, we set the thread wakeup flag.
+ */
+static inline bool sq_ring_needs_enter(struct io_uring *ring, unsigned *flags)
+{
+	if (!(ring->flags & IORING_SETUP_SQPOLL))
+		return true;
+
+	if (uring_unlikely(IO_URING_READ_ONCE(*ring->sq.kflags) &
+			   IORING_SQ_NEED_WAKEUP)) {
+		*flags |= IORING_ENTER_SQ_WAKEUP;
+		return true;
+	}
+
+	return false;
+}
+
+static inline bool cq_ring_needs_flush(struct io_uring *ring)
+{
+	return IO_URING_READ_ONCE(*ring->sq.kflags) & IORING_SQ_CQ_OVERFLOW;
+}
+
+static int __io_uring_peek_cqe(struct io_uring *ring,
+			       struct io_uring_cqe **cqe_ptr,
+			       unsigned *nr_available)
+{
+	struct io_uring_cqe *cqe;
+	int err = 0;
+	unsigned available;
+	unsigned mask = *ring->cq.kring_mask;
+
+	do {
+		unsigned tail = io_uring_smp_load_acquire(ring->cq.ktail);
+		unsigned head = *ring->cq.khead;
+
+		cqe = NULL;
+		available = tail - head;
+		if (!available)
+			break;
+
+		cqe = &ring->cq.cqes[head & mask];
+		if (!(ring->features & IORING_FEAT_EXT_ARG) &&
+				cqe->user_data == LIBURING_UDATA_TIMEOUT) {
+			if (cqe->res < 0)
+				err = cqe->res;
+			io_uring_cq_advance(ring, 1);
+			if (!err)
+				continue;
+			cqe = NULL;
+		}
+
+		break;
+	} while (1);
+
+	*cqe_ptr = cqe;
+	*nr_available = available;
+	return err;
+}
+
+struct get_data {
+	unsigned submit;
+	unsigned wait_nr;
+	unsigned get_flags;
+	int sz;
+	void *arg;
+};
+
+static int _io_uring_get_cqe(struct io_uring *ring, struct io_uring_cqe **cqe_ptr,
+			     struct get_data *data)
+{
+	struct io_uring_cqe *cqe = NULL;
+	int err;
+
+	do {
+		bool need_enter = false;
+		bool cq_overflow_flush = false;
+		unsigned flags = 0;
+		unsigned nr_available;
+		int ret;
+
+		err = __io_uring_peek_cqe(ring, &cqe, &nr_available);
+		if (err)
+			break;
+		if (!cqe && !data->wait_nr && !data->submit) {
+			if (!cq_ring_needs_flush(ring)) {
+				err = -EAGAIN;
+				break;
+			}
+			cq_overflow_flush = true;
+		}
+		if (data->wait_nr > nr_available || cq_overflow_flush) {
+			flags = IORING_ENTER_GETEVENTS | data->get_flags;
+			need_enter = true;
+		}
+		if (data->submit) {
+			sq_ring_needs_enter(ring, &flags);
+			need_enter = true;
+		}
+		if (!need_enter)
+			break;
+
+		ret = __sys_io_uring_enter2(ring->ring_fd, data->submit,
+				data->wait_nr, flags, data->arg,
+				data->sz);
+		if (ret < 0) {
+			err = -errno;
+			break;
+		}
+
+		data->submit -= ret;
+		if (cqe)
+			break;
+	} while (1);
+
+	*cqe_ptr = cqe;
+	return err;
+}
+
+int __io_uring_get_cqe(struct io_uring *ring, struct io_uring_cqe **cqe_ptr,
+		       unsigned submit, unsigned wait_nr, sigset_t *sigmask)
+{
+	struct get_data data = {
+		.submit		= submit,
+		.wait_nr 	= wait_nr,
+		.get_flags	= 0,
+		.sz		= _NSIG / 8,
+		.arg		= sigmask,
+	};
+
+	return _io_uring_get_cqe(ring, cqe_ptr, &data);
+}
+
+/*
+ * Fill in an array of IO completions up to count, if any are available.
+ * Returns the amount of IO completions filled.
+ */
+unsigned io_uring_peek_batch_cqe(struct io_uring *ring,
+				 struct io_uring_cqe **cqes, unsigned count)
+{
+	unsigned ready;
+	bool overflow_checked = false;
+
+again:
+	ready = io_uring_cq_ready(ring);
+	if (ready) {
+		unsigned head = *ring->cq.khead;
+		unsigned mask = *ring->cq.kring_mask;
+		unsigned last;
+		int i = 0;
+
+		count = count > ready ? ready : count;
+		last = head + count;
+		for (;head != last; head++, i++)
+			cqes[i] = &ring->cq.cqes[head & mask];
+
+		return count;
+	}
+
+	if (overflow_checked)
+		goto done;
+
+	if (cq_ring_needs_flush(ring)) {
+		__sys_io_uring_enter(ring->ring_fd, 0, 0,
+				     IORING_ENTER_GETEVENTS, NULL);
+		overflow_checked = true;
+		goto again;
+	}
+
+done:
+	return 0;
+}
+
+/*
+ * Sync internal state with kernel ring state on the SQ side. Returns the
+ * number of pending items in the SQ ring, for the shared ring.
+ */
+int __io_uring_flush_sq(struct io_uring *ring)
+{
+	struct io_uring_sq *sq = &ring->sq;
+	const unsigned mask = *sq->kring_mask;
+	unsigned ktail = *sq->ktail;
+	unsigned to_submit = sq->sqe_tail - sq->sqe_head;
+
+	if (!to_submit)
+		goto out;
+
+	/*
+	 * Fill in sqes that we have queued up, adding them to the kernel ring
+	 */
+	do {
+		sq->array[ktail & mask] = sq->sqe_head & mask;
+		ktail++;
+		sq->sqe_head++;
+	} while (--to_submit);
+
+	/*
+	 * Ensure that the kernel sees the SQE updates before it sees the tail
+	 * update.
+	 */
+	io_uring_smp_store_release(sq->ktail, ktail);
+out:
+	/*
+	 * This _may_ look problematic, as we're not supposed to be reading
+	 * SQ->head without acquire semantics. When we're in SQPOLL mode, the
+	 * kernel submitter could be updating this right now. For non-SQPOLL,
+	 * task itself does it, and there's no potential race. But even for
+	 * SQPOLL, the load is going to be potentially out-of-date the very
+	 * instant it's done, regardless or whether or not it's done
+	 * atomically. Worst case, we're going to be over-estimating what
+	 * we can submit. The point is, we need to be able to deal with this
+	 * situation regardless of any perceived atomicity.
+	 */
+	return ktail - *sq->khead;
+}
+
+/*
+ * If we have kernel support for IORING_ENTER_EXT_ARG, then we can use that
+ * more efficiently than queueing an internal timeout command.
+ */
+static int io_uring_wait_cqes_new(struct io_uring *ring,
+				  struct io_uring_cqe **cqe_ptr,
+				  unsigned wait_nr, struct __kernel_timespec *ts,
+				  sigset_t *sigmask)
+{
+	struct io_uring_getevents_arg arg = {
+		.sigmask	= (unsigned long) sigmask,
+		.sigmask_sz	= _NSIG / 8,
+		.ts		= (unsigned long) ts
+	};
+	struct get_data data = {
+		.submit		= __io_uring_flush_sq(ring),
+		.wait_nr	= wait_nr,
+		.get_flags	= IORING_ENTER_EXT_ARG,
+		.sz		= sizeof(arg),
+		.arg		= &arg
+	};
+
+	return _io_uring_get_cqe(ring, cqe_ptr, &data);
+}
+
+/*
+ * Like io_uring_wait_cqe(), except it accepts a timeout value as well. Note
+ * that an sqe is used internally to handle the timeout. For kernel doesn't
+ * support IORING_FEAT_EXT_ARG, applications using this function must never
+ * set sqe->user_data to LIBURING_UDATA_TIMEOUT!
+ *
+ * For kernels without IORING_FEAT_EXT_ARG (5.10 and older), if 'ts' is
+ * specified, the application need not call io_uring_submit() before
+ * calling this function, as we will do that on its behalf. From this it also
+ * follows that this function isn't safe to use for applications that split SQ
+ * and CQ handling between two threads and expect that to work without
+ * synchronization, as this function manipulates both the SQ and CQ side.
+ *
+ * For kernels with IORING_FEAT_EXT_ARG, no implicit submission is done and
+ * hence this function is safe to use for applications that split SQ and CQ
+ * handling between two threads.
+ */
+int io_uring_wait_cqes(struct io_uring *ring, struct io_uring_cqe **cqe_ptr,
+		       unsigned wait_nr, struct __kernel_timespec *ts,
+		       sigset_t *sigmask)
+{
+	unsigned to_submit = 0;
+
+	if (ts) {
+		struct io_uring_sqe *sqe;
+		int ret;
+
+		if (ring->features & IORING_FEAT_EXT_ARG)
+			return io_uring_wait_cqes_new(ring, cqe_ptr, wait_nr,
+							ts, sigmask);
+
+		/*
+		 * If the SQ ring is full, we may need to submit IO first
+		 */
+		sqe = io_uring_get_sqe(ring);
+		if (!sqe) {
+			ret = io_uring_submit(ring);
+			if (ret < 0)
+				return ret;
+			sqe = io_uring_get_sqe(ring);
+			if (!sqe)
+				return -EAGAIN;
+		}
+		io_uring_prep_timeout(sqe, ts, wait_nr, 0);
+		sqe->user_data = LIBURING_UDATA_TIMEOUT;
+		to_submit = __io_uring_flush_sq(ring);
+	}
+
+	return __io_uring_get_cqe(ring, cqe_ptr, to_submit, wait_nr, sigmask);
+}
+
+/*
+ * See io_uring_wait_cqes() - this function is the same, it just always uses
+ * '1' as the wait_nr.
+ */
+int io_uring_wait_cqe_timeout(struct io_uring *ring,
+			      struct io_uring_cqe **cqe_ptr,
+			      struct __kernel_timespec *ts)
+{
+	return io_uring_wait_cqes(ring, cqe_ptr, 1, ts, NULL);
+}
+
+/*
+ * Submit sqes acquired from io_uring_get_sqe() to the kernel.
+ *
+ * Returns number of sqes submitted
+ */
+static int __io_uring_submit(struct io_uring *ring, unsigned submitted,
+			     unsigned wait_nr)
+{
+	unsigned flags;
+	int ret;
+
+	flags = 0;
+	if (sq_ring_needs_enter(ring, &flags) || wait_nr) {
+		if (wait_nr || (ring->flags & IORING_SETUP_IOPOLL))
+			flags |= IORING_ENTER_GETEVENTS;
+
+		ret = __sys_io_uring_enter(ring->ring_fd, submitted, wait_nr,
+						flags, NULL);
+		if (ret < 0)
+			return -errno;
+	} else
+		ret = submitted;
+
+	return ret;
+}
+
+static int __io_uring_submit_and_wait(struct io_uring *ring, unsigned wait_nr)
+{
+	return __io_uring_submit(ring, __io_uring_flush_sq(ring), wait_nr);
+}
+
+/*
+ * Submit sqes acquired from io_uring_get_sqe() to the kernel.
+ *
+ * Returns number of sqes submitted
+ */
+int io_uring_submit(struct io_uring *ring)
+{
+	return __io_uring_submit_and_wait(ring, 0);
+}
+
+/*
+ * Like io_uring_submit(), but allows waiting for events as well.
+ *
+ * Returns number of sqes submitted
+ */
+int io_uring_submit_and_wait(struct io_uring *ring, unsigned wait_nr)
+{
+	return __io_uring_submit_and_wait(ring, wait_nr);
+}
+
+/*
+ * Return an sqe to fill. Application must later call io_uring_submit()
+ * when it's ready to tell the kernel about it. The caller may call this
+ * function multiple times before calling io_uring_submit().
+ *
+ * Returns a vacant sqe, or NULL if we're full.
+ */
+struct io_uring_sqe *io_uring_get_sqe(struct io_uring *ring)
+{
+	struct io_uring_sq *sq = &ring->sq;
+	unsigned int head = io_uring_smp_load_acquire(sq->khead);
+	unsigned int next = sq->sqe_tail + 1;
+	struct io_uring_sqe *sqe = NULL;
+
+	if (next - head <= *sq->kring_entries) {
+		sqe = &sq->sqes[sq->sqe_tail & *sq->kring_mask];
+		sq->sqe_tail = next;
+	}
+	return sqe;
+}
+
+int __io_uring_sqring_wait(struct io_uring *ring)
+{
+	int ret;
+
+	ret = __sys_io_uring_enter(ring->ring_fd, 0, 0, IORING_ENTER_SQ_WAIT,
+					NULL);
+	if (ret < 0)
+		ret = -errno;
+	return ret;
+}
diff --git a/src/register.c b/src/register.c
new file mode 100644
index 0000000..994aaff
--- /dev/null
+++ b/src/register.c
@@ -0,0 +1,189 @@
+/* SPDX-License-Identifier: MIT */
+#define _POSIX_C_SOURCE 200112L
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+
+#include "liburing/compat.h"
+#include "liburing/io_uring.h"
+#include "liburing.h"
+
+#include "syscall.h"
+
+int io_uring_register_buffers(struct io_uring *ring, const struct iovec *iovecs,
+			      unsigned nr_iovecs)
+{
+	int ret;
+
+	ret = __sys_io_uring_register(ring->ring_fd, IORING_REGISTER_BUFFERS,
+					iovecs, nr_iovecs);
+	if (ret < 0)
+		return -errno;
+
+	return 0;
+}
+
+int io_uring_unregister_buffers(struct io_uring *ring)
+{
+	int ret;
+
+	ret = __sys_io_uring_register(ring->ring_fd, IORING_UNREGISTER_BUFFERS,
+					NULL, 0);
+	if (ret < 0)
+		return -errno;
+
+	return 0;
+}
+
+/*
+ * Register an update for an existing file set. The updates will start at
+ * 'off' in the original array, and 'nr_files' is the number of files we'll
+ * update.
+ *
+ * Returns number of files updated on success, -ERROR on failure.
+ */
+int io_uring_register_files_update(struct io_uring *ring, unsigned off,
+				   int *files, unsigned nr_files)
+{
+	struct io_uring_files_update up = {
+		.offset	= off,
+		.fds	= (unsigned long) files,
+	};
+	int ret;
+
+	ret = __sys_io_uring_register(ring->ring_fd,
+					IORING_REGISTER_FILES_UPDATE, &up,
+					nr_files);
+	if (ret < 0)
+		return -errno;
+
+	return ret;
+}
+
+int io_uring_register_files(struct io_uring *ring, const int *files,
+			      unsigned nr_files)
+{
+	int ret;
+
+	ret = __sys_io_uring_register(ring->ring_fd, IORING_REGISTER_FILES,
+					files, nr_files);
+	if (ret < 0)
+		return -errno;
+
+	return 0;
+}
+
+int io_uring_unregister_files(struct io_uring *ring)
+{
+	int ret;
+
+	ret = __sys_io_uring_register(ring->ring_fd, IORING_UNREGISTER_FILES,
+					NULL, 0);
+	if (ret < 0)
+		return -errno;
+
+	return 0;
+}
+
+int io_uring_register_eventfd(struct io_uring *ring, int event_fd)
+{
+	int ret;
+
+	ret = __sys_io_uring_register(ring->ring_fd, IORING_REGISTER_EVENTFD,
+					&event_fd, 1);
+	if (ret < 0)
+		return -errno;
+
+	return 0;
+}
+
+int io_uring_unregister_eventfd(struct io_uring *ring)
+{
+	int ret;
+
+	ret = __sys_io_uring_register(ring->ring_fd, IORING_UNREGISTER_EVENTFD,
+					NULL, 0);
+	if (ret < 0)
+		return -errno;
+
+	return 0;
+}
+
+int io_uring_register_eventfd_async(struct io_uring *ring, int event_fd)
+{
+	int ret;
+
+	ret = __sys_io_uring_register(ring->ring_fd, IORING_REGISTER_EVENTFD_ASYNC,
+			&event_fd, 1);
+	if (ret < 0)
+		return -errno;
+
+	return 0;
+}
+
+int io_uring_register_probe(struct io_uring *ring, struct io_uring_probe *p,
+			    unsigned int nr_ops)
+{
+	int ret;
+
+	ret = __sys_io_uring_register(ring->ring_fd, IORING_REGISTER_PROBE,
+					p, nr_ops);
+	if (ret < 0)
+		return -errno;
+
+	return 0;
+}
+
+int io_uring_register_personality(struct io_uring *ring)
+{
+	int ret;
+
+	ret = __sys_io_uring_register(ring->ring_fd, IORING_REGISTER_PERSONALITY,
+					NULL, 0);
+	if (ret < 0)
+		return -errno;
+
+	return ret;
+}
+
+int io_uring_unregister_personality(struct io_uring *ring, int id)
+{
+	int ret;
+
+	ret = __sys_io_uring_register(ring->ring_fd, IORING_UNREGISTER_PERSONALITY,
+					NULL, id);
+	if (ret < 0)
+		return -errno;
+
+	return ret;
+}
+
+int io_uring_register_restrictions(struct io_uring *ring,
+				   struct io_uring_restriction *res,
+				   unsigned int nr_res)
+{
+	int ret;
+
+	ret = __sys_io_uring_register(ring->ring_fd, IORING_REGISTER_RESTRICTIONS,
+				      res, nr_res);
+	if (ret < 0)
+		return -errno;
+
+	return 0;
+}
+
+int io_uring_enable_rings(struct io_uring *ring)
+{
+	int ret;
+
+	ret = __sys_io_uring_register(ring->ring_fd,
+				      IORING_REGISTER_ENABLE_RINGS, NULL, 0);
+	if (ret < 0)
+		return -errno;
+
+	return ret;
+}
diff --git a/src/setup.c b/src/setup.c
new file mode 100644
index 0000000..54225e8
--- /dev/null
+++ b/src/setup.c
@@ -0,0 +1,356 @@
+/* SPDX-License-Identifier: MIT */
+#define _DEFAULT_SOURCE
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <stdlib.h>
+#include <signal.h>
+
+#include "liburing/compat.h"
+#include "liburing/io_uring.h"
+#include "liburing.h"
+
+#include "syscall.h"
+
+static void io_uring_unmap_rings(struct io_uring_sq *sq, struct io_uring_cq *cq)
+{
+	munmap(sq->ring_ptr, sq->ring_sz);
+	if (cq->ring_ptr && cq->ring_ptr != sq->ring_ptr)
+		munmap(cq->ring_ptr, cq->ring_sz);
+}
+
+static int io_uring_mmap(int fd, struct io_uring_params *p,
+			 struct io_uring_sq *sq, struct io_uring_cq *cq)
+{
+	size_t size;
+	int ret;
+
+	sq->ring_sz = p->sq_off.array + p->sq_entries * sizeof(unsigned);
+	cq->ring_sz = p->cq_off.cqes + p->cq_entries * sizeof(struct io_uring_cqe);
+
+	if (p->features & IORING_FEAT_SINGLE_MMAP) {
+		if (cq->ring_sz > sq->ring_sz)
+			sq->ring_sz = cq->ring_sz;
+		cq->ring_sz = sq->ring_sz;
+	}
+	sq->ring_ptr = mmap(0, sq->ring_sz, PROT_READ | PROT_WRITE,
+			MAP_SHARED | MAP_POPULATE, fd, IORING_OFF_SQ_RING);
+	if (sq->ring_ptr == MAP_FAILED)
+		return -errno;
+
+	if (p->features & IORING_FEAT_SINGLE_MMAP) {
+		cq->ring_ptr = sq->ring_ptr;
+	} else {
+		cq->ring_ptr = mmap(0, cq->ring_sz, PROT_READ | PROT_WRITE,
+				MAP_SHARED | MAP_POPULATE, fd, IORING_OFF_CQ_RING);
+		if (cq->ring_ptr == MAP_FAILED) {
+			cq->ring_ptr = NULL;
+			ret = -errno;
+			goto err;
+		}
+	}
+
+	sq->khead = sq->ring_ptr + p->sq_off.head;
+	sq->ktail = sq->ring_ptr + p->sq_off.tail;
+	sq->kring_mask = sq->ring_ptr + p->sq_off.ring_mask;
+	sq->kring_entries = sq->ring_ptr + p->sq_off.ring_entries;
+	sq->kflags = sq->ring_ptr + p->sq_off.flags;
+	sq->kdropped = sq->ring_ptr + p->sq_off.dropped;
+	sq->array = sq->ring_ptr + p->sq_off.array;
+
+	size = p->sq_entries * sizeof(struct io_uring_sqe);
+	sq->sqes = mmap(0, size, PROT_READ | PROT_WRITE,
+				MAP_SHARED | MAP_POPULATE, fd,
+				IORING_OFF_SQES);
+	if (sq->sqes == MAP_FAILED) {
+		ret = -errno;
+err:
+		io_uring_unmap_rings(sq, cq);
+		return ret;
+	}
+
+	cq->khead = cq->ring_ptr + p->cq_off.head;
+	cq->ktail = cq->ring_ptr + p->cq_off.tail;
+	cq->kring_mask = cq->ring_ptr + p->cq_off.ring_mask;
+	cq->kring_entries = cq->ring_ptr + p->cq_off.ring_entries;
+	cq->koverflow = cq->ring_ptr + p->cq_off.overflow;
+	cq->cqes = cq->ring_ptr + p->cq_off.cqes;
+	if (p->cq_off.flags)
+		cq->kflags = cq->ring_ptr + p->cq_off.flags;
+	return 0;
+}
+
+/*
+ * For users that want to specify sq_thread_cpu or sq_thread_idle, this
+ * interface is a convenient helper for mmap()ing the rings.
+ * Returns -errno on error, or zero on success.  On success, 'ring'
+ * contains the necessary information to read/write to the rings.
+ */
+int io_uring_queue_mmap(int fd, struct io_uring_params *p, struct io_uring *ring)
+{
+	int ret;
+
+	memset(ring, 0, sizeof(*ring));
+	ret = io_uring_mmap(fd, p, &ring->sq, &ring->cq);
+	if (!ret) {
+		ring->flags = p->flags;
+		ring->ring_fd = fd;
+	}
+	return ret;
+}
+
+/*
+ * Ensure that the mmap'ed rings aren't available to a child after a fork(2).
+ * This uses madvise(..., MADV_DONTFORK) on the mmap'ed ranges.
+ */
+int io_uring_ring_dontfork(struct io_uring *ring)
+{
+	size_t len;
+	int ret;
+
+	if (!ring->sq.ring_ptr || !ring->sq.sqes || !ring->cq.ring_ptr)
+		return -EINVAL;
+
+	len = *ring->sq.kring_entries * sizeof(struct io_uring_sqe);
+	ret = madvise(ring->sq.sqes, len, MADV_DONTFORK);
+	if (ret == -1)
+		return -errno;
+
+	len = ring->sq.ring_sz;
+	ret = madvise(ring->sq.ring_ptr, len, MADV_DONTFORK);
+	if (ret == -1)
+		return -errno;
+
+	if (ring->cq.ring_ptr != ring->sq.ring_ptr) {
+		len = ring->cq.ring_sz;
+		ret = madvise(ring->cq.ring_ptr, len, MADV_DONTFORK);
+		if (ret == -1)
+			return -errno;
+	}
+
+	return 0;
+}
+
+int io_uring_queue_init_params(unsigned entries, struct io_uring *ring,
+			       struct io_uring_params *p)
+{
+	int fd, ret;
+
+	fd = __sys_io_uring_setup(entries, p);
+	if (fd < 0)
+		return -errno;
+
+	ret = io_uring_queue_mmap(fd, p, ring);
+	if (ret) {
+		close(fd);
+		return ret;
+	}
+
+	ring->features = p->features;
+	return 0;
+}
+
+/*
+ * Returns -errno on error, or zero on success. On success, 'ring'
+ * contains the necessary information to read/write to the rings.
+ */
+int io_uring_queue_init(unsigned entries, struct io_uring *ring, unsigned flags)
+{
+	struct io_uring_params p;
+
+	memset(&p, 0, sizeof(p));
+	p.flags = flags;
+
+	return io_uring_queue_init_params(entries, ring, &p);
+}
+
+void io_uring_queue_exit(struct io_uring *ring)
+{
+	struct io_uring_sq *sq = &ring->sq;
+	struct io_uring_cq *cq = &ring->cq;
+
+	munmap(sq->sqes, *sq->kring_entries * sizeof(struct io_uring_sqe));
+	io_uring_unmap_rings(sq, cq);
+	close(ring->ring_fd);
+}
+
+struct io_uring_probe *io_uring_get_probe_ring(struct io_uring *ring)
+{
+	struct io_uring_probe *probe;
+	size_t len;
+	int r;
+
+	len = sizeof(*probe) + 256 * sizeof(struct io_uring_probe_op);
+	probe = malloc(len);
+	if (!probe)
+		return NULL;
+	memset(probe, 0, len);
+
+	r = io_uring_register_probe(ring, probe, 256);
+	if (r >= 0)
+		return probe;
+
+	free(probe);
+	return NULL;
+}
+
+struct io_uring_probe *io_uring_get_probe(void)
+{
+	struct io_uring ring;
+	struct io_uring_probe *probe;
+	int r;
+
+	r = io_uring_queue_init(2, &ring, 0);
+	if (r < 0)
+		return NULL;
+
+	probe = io_uring_get_probe_ring(&ring);
+	io_uring_queue_exit(&ring);
+	return probe;
+}
+
+void io_uring_free_probe(struct io_uring_probe *probe)
+{
+	free(probe);
+}
+
+static int __fls(int x)
+{
+	int r = 32;
+
+	if (!x)
+		return 0;
+	if (!(x & 0xffff0000u)) {
+		x <<= 16;
+		r -= 16;
+	}
+	if (!(x & 0xff000000u)) {
+		x <<= 8;
+		r -= 8;
+	}
+	if (!(x & 0xf0000000u)) {
+		x <<= 4;
+		r -= 4;
+	}
+	if (!(x & 0xc0000000u)) {
+		x <<= 2;
+		r -= 2;
+	}
+	if (!(x & 0x80000000u)) {
+		x <<= 1;
+		r -= 1;
+	}
+	return r;
+}
+
+static unsigned roundup_pow2(unsigned depth)
+{
+	return 1UL << __fls(depth - 1);
+}
+
+static size_t npages(size_t size, unsigned page_size)
+{
+	size--;
+	size /= page_size;
+	return __fls(size);
+}
+
+#define KRING_SIZE	320
+
+static size_t rings_size(unsigned entries, unsigned cq_entries, unsigned page_size)
+{
+	size_t pages, sq_size, cq_size;
+
+	cq_size = KRING_SIZE;
+	cq_size += cq_entries * sizeof(struct io_uring_cqe);
+	cq_size = (cq_size + 63) & ~63UL;
+	pages = (size_t) 1 << npages(cq_size, page_size);
+
+	sq_size = sizeof(struct io_uring_sqe) * entries;
+	pages += (size_t) 1 << npages(sq_size, page_size);
+	return pages * page_size;
+}
+
+#define KERN_MAX_ENTRIES	32768
+#define KERN_MAX_CQ_ENTRIES	(2 * KERN_MAX_ENTRIES)
+
+/*
+ * Return the required ulimit -l memlock memory required for a given ring
+ * setup, in bytes. May return -errno on error. On newer (5.12+) kernels,
+ * io_uring no longer requires any memlock memory, and hence this function
+ * will return 0 for that case. On older (5.11 and prior) kernels, this will
+ * return the required memory so that the caller can ensure that enough space
+ * is available before setting up a ring with the specified parameters.
+ */
+ssize_t io_uring_mlock_size_params(unsigned entries, struct io_uring_params *p)
+{
+	struct io_uring_params lp = { };
+	struct io_uring ring;
+	unsigned cq_entries;
+	long page_size;
+	ssize_t ret;
+
+	/*
+	 * We only really use this inited ring to see if the kernel is newer
+	 * or not. Newer kernels don't require memlocked memory. If we fail,
+	 * it's most likely because it's an older kernel and we have no
+	 * available memlock space. Just continue on, lp.features will still
+	 * be zeroed at this point and we'll do the right thing.
+	 */
+	ret = io_uring_queue_init_params(entries, &ring, &lp);
+	if (!ret)
+		io_uring_queue_exit(&ring);
+
+	/*
+	 * Native workers imply using cgroup memory accounting, and hence no
+	 * memlock memory is needed for the ring allocations.
+	 */
+	if (lp.features & IORING_FEAT_NATIVE_WORKERS)
+		return 0;
+
+	if (!entries)
+		return -EINVAL;
+	if (entries > KERN_MAX_ENTRIES) {
+		if (!(p->flags & IORING_SETUP_CLAMP))
+			return -EINVAL;
+		entries = KERN_MAX_ENTRIES;
+	}
+
+	entries = roundup_pow2(entries);
+	if (p->flags & IORING_SETUP_CQSIZE) {
+		if (!p->cq_entries)
+			return -EINVAL;
+		cq_entries = p->cq_entries;
+		if (cq_entries > KERN_MAX_CQ_ENTRIES) {
+			if (!(p->flags & IORING_SETUP_CLAMP))
+				return -EINVAL;
+			cq_entries = KERN_MAX_CQ_ENTRIES;
+		}
+		cq_entries = roundup_pow2(cq_entries);
+		if (cq_entries < entries)
+			return -EINVAL;
+	} else {
+		cq_entries = 2 * entries;
+	}
+
+	page_size = sysconf(_SC_PAGESIZE);
+	if (page_size < 0)
+		page_size = 4096;
+
+	return rings_size(entries, cq_entries, page_size);
+}
+
+/*
+ * Return required ulimit -l memory space for a given ring setup. See
+ * @io_uring_mlock_size_params().
+ */
+ssize_t io_uring_mlock_size(unsigned entries, unsigned flags)
+{
+	struct io_uring_params p = { .flags = flags, };
+
+	return io_uring_mlock_size_params(entries, &p);
+}
diff --git a/src/syscall.c b/src/syscall.c
new file mode 100644
index 0000000..2fd3dd4
--- /dev/null
+++ b/src/syscall.c
@@ -0,0 +1,63 @@
+/* SPDX-License-Identifier: MIT */
+#define _DEFAULT_SOURCE
+
+/*
+ * Will go away once libc support is there
+ */
+#include <unistd.h>
+#include <sys/syscall.h>
+#include <sys/uio.h>
+#include "liburing/compat.h"
+#include "liburing/io_uring.h"
+#include "syscall.h"
+
+#ifdef __alpha__
+/*
+ * alpha is the only exception, all other architectures
+ * have common numbers for new system calls.
+ */
+# ifndef __NR_io_uring_setup
+#  define __NR_io_uring_setup		535
+# endif
+# ifndef __NR_io_uring_enter
+#  define __NR_io_uring_enter		536
+# endif
+# ifndef __NR_io_uring_register
+#  define __NR_io_uring_register	537
+# endif
+#else /* !__alpha__ */
+# ifndef __NR_io_uring_setup
+#  define __NR_io_uring_setup		425
+# endif
+# ifndef __NR_io_uring_enter
+#  define __NR_io_uring_enter		426
+# endif
+# ifndef __NR_io_uring_register
+#  define __NR_io_uring_register	427
+# endif
+#endif
+
+int __sys_io_uring_register(int fd, unsigned opcode, const void *arg,
+			    unsigned nr_args)
+{
+	return syscall(__NR_io_uring_register, fd, opcode, arg, nr_args);
+}
+
+int __sys_io_uring_setup(unsigned entries, struct io_uring_params *p)
+{
+	return syscall(__NR_io_uring_setup, entries, p);
+}
+
+int __sys_io_uring_enter2(int fd, unsigned to_submit, unsigned min_complete,
+			 unsigned flags, sigset_t *sig, int sz)
+{
+	return syscall(__NR_io_uring_enter, fd, to_submit, min_complete,
+			flags, sig, sz);
+}
+
+int __sys_io_uring_enter(int fd, unsigned to_submit, unsigned min_complete,
+			 unsigned flags, sigset_t *sig)
+{
+	return __sys_io_uring_enter2(fd, to_submit, min_complete, flags, sig,
+					_NSIG / 8);
+}
diff --git a/src/syscall.h b/src/syscall.h
new file mode 100644
index 0000000..3b94efc
--- /dev/null
+++ b/src/syscall.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: MIT */
+#ifndef LIBURING_SYSCALL_H
+#define LIBURING_SYSCALL_H
+
+#include <signal.h>
+
+struct io_uring_params;
+
+/*
+ * System calls
+ */
+extern int __sys_io_uring_setup(unsigned entries, struct io_uring_params *p);
+extern int __sys_io_uring_enter(int fd, unsigned to_submit,
+	unsigned min_complete, unsigned flags, sigset_t *sig);
+extern int __sys_io_uring_enter2(int fd, unsigned to_submit,
+	unsigned min_complete, unsigned flags, sigset_t *sig, int sz);
+extern int __sys_io_uring_register(int fd, unsigned int opcode, const void *arg,
+	unsigned int nr_args);
+
+#endif
diff --git a/test/232c93d07b74-test.c b/test/232c93d07b74-test.c
new file mode 100644
index 0000000..cd194cb
--- /dev/null
+++ b/test/232c93d07b74-test.c
@@ -0,0 +1,305 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Test case for socket read/write through IORING_OP_READV and
+ * IORING_OP_WRITEV, using both TCP and sockets and blocking and
+ * non-blocking IO.
+ *
+ * Heavily based on a test case from Hrvoje Zeba <zeba.hrvoje@gmail.com>
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <assert.h>
+
+#include <pthread.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <netinet/tcp.h>
+#include <netinet/in.h>
+
+#include "liburing.h"
+
+#define RECV_BUFF_SIZE 2
+#define SEND_BUFF_SIZE 3
+
+#define PORT	0x1235
+
+struct params {
+	int tcp;
+	int non_blocking;
+};
+
+pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
+pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
+int rcv_ready = 0;
+
+static void set_rcv_ready(void)
+{
+	pthread_mutex_lock(&mutex);
+
+	rcv_ready = 1;
+	pthread_cond_signal(&cond);
+
+	pthread_mutex_unlock(&mutex);
+}
+
+static void wait_for_rcv_ready(void)
+{
+	pthread_mutex_lock(&mutex);
+
+	while (!rcv_ready)
+		pthread_cond_wait(&cond, &mutex);
+
+	pthread_mutex_unlock(&mutex);
+}
+
+static void *rcv(void *arg)
+{
+	struct params *p = arg;
+	int s0;
+	int res;
+
+	if (p->tcp) {
+		int val = 1;
+                
+
+		s0 = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, IPPROTO_TCP);
+		res = setsockopt(s0, SOL_SOCKET, SO_REUSEPORT, &val, sizeof(val));
+		assert(res != -1);
+		res = setsockopt(s0, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
+		assert(res != -1);
+
+		struct sockaddr_in addr;
+
+		addr.sin_family = AF_INET;
+		addr.sin_port = PORT;
+		addr.sin_addr.s_addr = 0x0100007fU;
+		res = bind(s0, (struct sockaddr *) &addr, sizeof(addr));
+		assert(res != -1);
+	} else {
+		s0 = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
+		assert(s0 != -1);
+
+		struct sockaddr_un addr;
+		memset(&addr, 0, sizeof(addr));
+
+		addr.sun_family = AF_UNIX;
+		memcpy(addr.sun_path, "\0sock", 6);
+		res = bind(s0, (struct sockaddr *) &addr, sizeof(addr));
+		assert(res != -1);
+	}
+	res = listen(s0, 128);
+	assert(res != -1);
+
+	set_rcv_ready();
+
+	int s1 = accept(s0, NULL, NULL);
+	assert(s1 != -1);
+
+	if (p->non_blocking) {
+		int flags = fcntl(s1, F_GETFL, 0);
+		assert(flags != -1);
+
+		flags |= O_NONBLOCK;
+		res = fcntl(s1, F_SETFL, flags);
+		assert(res != -1);
+	}
+
+	struct io_uring m_io_uring;
+	void *ret = NULL;
+
+	res = io_uring_queue_init(32, &m_io_uring, 0);
+	assert(res >= 0);
+
+	int bytes_read = 0;
+	int expected_byte = 0;
+	int done = 0;
+
+	while (!done && bytes_read != 33) {
+		char buff[RECV_BUFF_SIZE];
+		struct iovec iov;
+
+		iov.iov_base = buff;
+		iov.iov_len = sizeof(buff);
+
+		struct io_uring_sqe *sqe = io_uring_get_sqe(&m_io_uring);
+		assert(sqe != NULL);
+
+		io_uring_prep_readv(sqe, s1, &iov, 1, 0);
+
+		res = io_uring_submit(&m_io_uring);
+		assert(res != -1);
+
+		struct io_uring_cqe *cqe;
+		unsigned head;
+		unsigned count = 0;
+
+		while (!done && count != 1) {
+			io_uring_for_each_cqe(&m_io_uring, head, cqe) {
+				if (cqe->res < 0)
+					assert(cqe->res == -EAGAIN);
+				else {
+					int i;
+
+					for (i = 0; i < cqe->res; i++) {
+						if (buff[i] != expected_byte) {
+							fprintf(stderr,
+								"Received %d, wanted %d\n",
+								buff[i], expected_byte);
+							ret++;
+							done = 1;
+						 }
+						 expected_byte++;
+					}
+					bytes_read += cqe->res;
+				}
+
+				count++;
+			}
+
+			assert(count <= 1);
+			io_uring_cq_advance(&m_io_uring, count);
+		}
+	}
+
+	shutdown(s1, SHUT_RDWR);
+	close(s1);
+	close(s0);
+	io_uring_queue_exit(&m_io_uring);
+	return ret;
+}
+
+static void *snd(void *arg)
+{
+	struct params *p = arg;
+	int s0;
+	int ret;
+
+	wait_for_rcv_ready();
+
+	if (p->tcp) {
+		int val = 1;
+
+		s0 = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, IPPROTO_TCP);
+		ret = setsockopt(s0, IPPROTO_TCP, TCP_NODELAY, &val, sizeof(val));
+		assert(ret != -1);
+
+		struct sockaddr_in addr;
+
+		addr.sin_family = AF_INET;
+		addr.sin_port = PORT;
+		addr.sin_addr.s_addr = 0x0100007fU;
+		ret = connect(s0, (struct sockaddr*) &addr, sizeof(addr));
+		assert(ret != -1);
+	} else {
+		s0 = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
+		assert(s0 != -1);
+
+		struct sockaddr_un addr;
+		memset(&addr, 0, sizeof(addr));
+
+		addr.sun_family = AF_UNIX;
+		memcpy(addr.sun_path, "\0sock", 6);
+		ret = connect(s0, (struct sockaddr*) &addr, sizeof(addr));
+		assert(ret != -1);
+	}
+
+	if (p->non_blocking) {
+		int flags = fcntl(s0, F_GETFL, 0);
+		assert(flags != -1);
+
+		flags |= O_NONBLOCK;
+		ret = fcntl(s0, F_SETFL, flags);
+		assert(ret != -1);
+	}
+
+	struct io_uring m_io_uring;
+
+	ret = io_uring_queue_init(32, &m_io_uring, 0);
+	assert(ret >= 0);
+
+	int bytes_written = 0;
+	int done = 0;
+
+	while (!done && bytes_written != 33) {
+		char buff[SEND_BUFF_SIZE];
+		int i;
+
+		for (i = 0; i < SEND_BUFF_SIZE; i++)
+			buff[i] = i + bytes_written;
+
+		struct iovec iov;
+
+		iov.iov_base = buff;
+		iov.iov_len = sizeof(buff);
+
+		struct io_uring_sqe *sqe = io_uring_get_sqe(&m_io_uring);
+		assert(sqe != NULL);
+
+		io_uring_prep_writev(sqe, s0, &iov, 1, 0);
+
+		ret = io_uring_submit(&m_io_uring);
+		assert(ret != -1);
+
+		struct io_uring_cqe *cqe;
+		unsigned head;
+		unsigned count = 0;
+
+		while (!done && count != 1) {
+			io_uring_for_each_cqe(&m_io_uring, head, cqe) {
+				if (cqe->res < 0) {
+					if (cqe->res == -EPIPE) {
+						done = 1;
+						break;
+					}
+					assert(cqe->res == -EAGAIN);
+				} else {
+					bytes_written += cqe->res;
+				}
+
+				count++;
+			}
+
+			assert(count <= 1);
+			io_uring_cq_advance(&m_io_uring, count);
+		}
+		usleep(100000);
+	}
+
+	shutdown(s0, SHUT_RDWR);
+	close(s0);
+	io_uring_queue_exit(&m_io_uring);
+	return NULL;
+}
+
+int main(int argc, char *argv[])
+{
+	struct params p;
+	pthread_t t1, t2;
+	void *res1, *res2;
+	int i, exit_val = 0;
+
+	if (argc > 1)
+		return 0;
+
+	for (i = 0; i < 4; i++) {
+		p.tcp = i & 1;
+		p.non_blocking = (i & 2) >> 1;
+
+		rcv_ready = 0;
+
+		pthread_create(&t1, NULL, rcv, &p);
+		pthread_create(&t2, NULL, snd, &p);
+		pthread_join(t1, &res1);
+		pthread_join(t2, &res2);
+		if (res1 || res2) {
+			fprintf(stderr, "Failed tcp=%d, non_blocking=%d\n", p.tcp, p.non_blocking);
+			exit_val = 1;
+		}
+	}
+
+	return exit_val;
+}
diff --git a/test/35fa71a030ca-test.c b/test/35fa71a030ca-test.c
new file mode 100644
index 0000000..f5fcc4d
--- /dev/null
+++ b/test/35fa71a030ca-test.c
@@ -0,0 +1,326 @@
+/* SPDX-License-Identifier: MIT */
+// autogenerated by syzkaller (https://github.com/google/syzkaller)
+
+#include <dirent.h>
+#include <endian.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <pthread.h>
+#include <signal.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/prctl.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <time.h>
+#include <unistd.h>
+#include <sys/mman.h>
+
+#include <linux/futex.h>
+
+#include "liburing.h"
+#include "../src/syscall.h"
+
+#if !defined(SYS_futex) && defined(SYS_futex_time64)
+# define SYS_futex SYS_futex_time64
+#endif
+
+static void sleep_ms(uint64_t ms)
+{
+  usleep(ms * 1000);
+}
+
+static uint64_t current_time_ms(void)
+{
+  struct timespec ts;
+  if (clock_gettime(CLOCK_MONOTONIC, &ts))
+    exit(1);
+  return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000;
+}
+
+static void thread_start(void* (*fn)(void*), void* arg)
+{
+  pthread_t th;
+  pthread_attr_t attr;
+  pthread_attr_init(&attr);
+  pthread_attr_setstacksize(&attr, 128 << 10);
+  int i;
+  for (i = 0; i < 100; i++) {
+    if (pthread_create(&th, &attr, fn, arg) == 0) {
+      pthread_attr_destroy(&attr);
+      return;
+    }
+    if (errno == EAGAIN) {
+      usleep(50);
+      continue;
+    }
+    break;
+  }
+  exit(1);
+}
+
+typedef struct {
+  int state;
+} event_t;
+
+static void event_init(event_t* ev)
+{
+  ev->state = 0;
+}
+
+static void event_reset(event_t* ev)
+{
+  ev->state = 0;
+}
+
+static void event_set(event_t* ev)
+{
+  if (ev->state)
+    exit(1);
+  __atomic_store_n(&ev->state, 1, __ATOMIC_RELEASE);
+  syscall(SYS_futex, &ev->state, FUTEX_WAKE | FUTEX_PRIVATE_FLAG);
+}
+
+static void event_wait(event_t* ev)
+{
+  while (!__atomic_load_n(&ev->state, __ATOMIC_ACQUIRE))
+    syscall(SYS_futex, &ev->state, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, 0, 0);
+}
+
+static int event_isset(event_t* ev)
+{
+  return __atomic_load_n(&ev->state, __ATOMIC_ACQUIRE);
+}
+
+static int event_timedwait(event_t* ev, uint64_t timeout)
+{
+  uint64_t start = current_time_ms();
+  uint64_t now = start;
+  for (;;) {
+    uint64_t remain = timeout - (now - start);
+    struct timespec ts;
+    ts.tv_sec = remain / 1000;
+    ts.tv_nsec = (remain % 1000) * 1000 * 1000;
+    syscall(SYS_futex, &ev->state, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, 0, &ts);
+    if (__atomic_load_n(&ev->state, __ATOMIC_RELAXED))
+      return 1;
+    now = current_time_ms();
+    if (now - start > timeout)
+      return 0;
+  }
+}
+
+static bool write_file(const char* file, const char* what, ...)
+{
+  char buf[1024];
+  va_list args;
+  va_start(args, what);
+  vsnprintf(buf, sizeof(buf), what, args);
+  va_end(args);
+  buf[sizeof(buf) - 1] = 0;
+  int len = strlen(buf);
+  int fd = open(file, O_WRONLY | O_CLOEXEC);
+  if (fd == -1)
+    return false;
+  if (write(fd, buf, len) != len) {
+    int err = errno;
+    close(fd);
+    errno = err;
+    return false;
+  }
+  close(fd);
+  return true;
+}
+
+static void kill_and_wait(int pid, int* status)
+{
+  kill(-pid, SIGKILL);
+  kill(pid, SIGKILL);
+  int i;
+  for (i = 0; i < 100; i++) {
+    if (waitpid(-1, status, WNOHANG | __WALL) == pid)
+      return;
+    usleep(1000);
+  }
+  DIR* dir = opendir("/sys/fs/fuse/connections");
+  if (dir) {
+    for (;;) {
+      struct dirent* ent = readdir(dir);
+      if (!ent)
+        break;
+      if (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0)
+        continue;
+      char abort[300];
+      snprintf(abort, sizeof(abort), "/sys/fs/fuse/connections/%s/abort",
+               ent->d_name);
+      int fd = open(abort, O_WRONLY);
+      if (fd == -1) {
+        continue;
+      }
+      if (write(fd, abort, 1) < 0) {
+      }
+      close(fd);
+    }
+    closedir(dir);
+  } else {
+  }
+  while (waitpid(-1, status, __WALL) != pid) {
+  }
+}
+
+#define SYZ_HAVE_SETUP_TEST 1
+static void setup_test()
+{
+  prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
+  setpgrp();
+  write_file("/proc/self/oom_score_adj", "1000");
+}
+
+struct thread_t {
+  int created, call;
+  event_t ready, done;
+};
+
+static struct thread_t threads[16];
+static void execute_call(int call);
+static int running;
+
+static void* thr(void* arg)
+{
+  struct thread_t* th = (struct thread_t*)arg;
+  for (;;) {
+    event_wait(&th->ready);
+    event_reset(&th->ready);
+    execute_call(th->call);
+    __atomic_fetch_sub(&running, 1, __ATOMIC_RELAXED);
+    event_set(&th->done);
+  }
+  return 0;
+}
+
+static void execute_one(void)
+{
+  int i, call, thread;
+  for (call = 0; call < 3; call++) {
+    for (thread = 0; thread < (int)(sizeof(threads) / sizeof(threads[0]));
+         thread++) {
+      struct thread_t* th = &threads[thread];
+      if (!th->created) {
+        th->created = 1;
+        event_init(&th->ready);
+        event_init(&th->done);
+        event_set(&th->done);
+        thread_start(thr, th);
+      }
+      if (!event_isset(&th->done))
+        continue;
+      event_reset(&th->done);
+      th->call = call;
+      __atomic_fetch_add(&running, 1, __ATOMIC_RELAXED);
+      event_set(&th->ready);
+      event_timedwait(&th->done, 45);
+      break;
+    }
+  }
+  for (i = 0; i < 100 && __atomic_load_n(&running, __ATOMIC_RELAXED); i++)
+    sleep_ms(1);
+}
+
+static void execute_one(void);
+
+#define WAIT_FLAGS __WALL
+
+static void loop(void)
+{
+  int iter;
+  for (iter = 0;; iter++) {
+    int pid = fork();
+    if (pid < 0)
+      exit(1);
+    if (pid == 0) {
+      setup_test();
+      execute_one();
+      exit(0);
+    }
+    int status = 0;
+    uint64_t start = current_time_ms();
+    for (;;) {
+      if (waitpid(-1, &status, WNOHANG | WAIT_FLAGS) == pid)
+        break;
+      sleep_ms(1);
+      if (current_time_ms() - start < 5 * 1000)
+        continue;
+      kill_and_wait(pid, &status);
+      break;
+    }
+  }
+}
+
+uint64_t r[1] = {0xffffffffffffffff};
+
+void execute_call(int call)
+{
+  long res;
+  switch (call) {
+  case 0:
+    *(uint32_t*)0x20000040 = 0;
+    *(uint32_t*)0x20000044 = 0;
+    *(uint32_t*)0x20000048 = 0;
+    *(uint32_t*)0x2000004c = 0;
+    *(uint32_t*)0x20000050 = 0;
+    *(uint32_t*)0x20000054 = 0;
+    *(uint32_t*)0x20000058 = 0;
+    *(uint32_t*)0x2000005c = 0;
+    *(uint32_t*)0x20000060 = 0;
+    *(uint32_t*)0x20000064 = 0;
+    *(uint32_t*)0x20000068 = 0;
+    *(uint32_t*)0x2000006c = 0;
+    *(uint32_t*)0x20000070 = 0;
+    *(uint32_t*)0x20000074 = 0;
+    *(uint32_t*)0x20000078 = 0;
+    *(uint32_t*)0x2000007c = 0;
+    *(uint32_t*)0x20000080 = 0;
+    *(uint32_t*)0x20000084 = 0;
+    *(uint64_t*)0x20000088 = 0;
+    *(uint32_t*)0x20000090 = 0;
+    *(uint32_t*)0x20000094 = 0;
+    *(uint32_t*)0x20000098 = 0;
+    *(uint32_t*)0x2000009c = 0;
+    *(uint32_t*)0x200000a0 = 0;
+    *(uint32_t*)0x200000a4 = 0;
+    *(uint32_t*)0x200000a8 = 0;
+    *(uint32_t*)0x200000ac = 0;
+    *(uint64_t*)0x200000b0 = 0;
+    res = __sys_io_uring_setup(0x64, (struct io_uring_params *) 0x20000040UL);
+    if (res != -1)
+      r[0] = res;
+    break;
+  case 1:
+    __sys_io_uring_register((long)r[0], 0, 0, 0);
+    break;
+  case 2:
+    __sys_io_uring_register((long)r[0], 0, 0, 0);
+    break;
+  }
+}
+
+static void sig_int(int sig)
+{
+	exit(0);
+}
+
+int main(int argc, char *argv[])
+{
+	if (argc > 1)
+		return 0;
+	signal(SIGINT, sig_int);
+	mmap((void *) 0x20000000, 0x1000000, 3, 0x32, -1, 0);
+	loop();
+	return 0;
+}
diff --git a/test/500f9fbadef8-test.c b/test/500f9fbadef8-test.c
new file mode 100644
index 0000000..dbd5751
--- /dev/null
+++ b/test/500f9fbadef8-test.c
@@ -0,0 +1,89 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: Single depth submit+wait poll hang test
+ *
+ */
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+
+#include "helpers.h"
+#include "liburing.h"
+
+#define BLOCKS	4096
+
+int main(int argc, char *argv[])
+{
+	struct io_uring ring;
+	struct io_uring_sqe *sqe;
+	struct io_uring_cqe *cqe;
+	struct iovec iov;
+	char buf[32];
+	off_t offset;
+	unsigned blocks;
+	int ret, fd;
+
+	if (argc > 1)
+		return 0;
+
+	t_posix_memalign(&iov.iov_base, 4096, 4096);
+	iov.iov_len = 4096;
+
+	ret = io_uring_queue_init(1, &ring, IORING_SETUP_IOPOLL);
+	if (ret) {
+		fprintf(stderr, "ring setup failed\n");
+		return 1;
+
+	}
+
+	sprintf(buf, "./XXXXXX");
+	fd = mkostemp(buf, O_WRONLY | O_DIRECT | O_CREAT);
+	if (fd < 0) {
+		perror("mkostemp");
+		return 1;
+	}
+
+	offset = 0;
+	blocks = BLOCKS;
+	do {
+		sqe = io_uring_get_sqe(&ring);
+		if (!sqe) {
+			fprintf(stderr, "get sqe failed\n");
+			goto err;
+		}
+		io_uring_prep_writev(sqe, fd, &iov, 1, offset);
+		ret = io_uring_submit_and_wait(&ring, 1);
+		if (ret < 0) {
+			fprintf(stderr, "submit_and_wait: %d\n", ret);
+			goto err;
+		}
+		ret = io_uring_wait_cqe(&ring, &cqe);
+		if (ret < 0) {
+			fprintf(stderr, "wait completion: %d\n", ret);
+			goto err;
+		}
+		if (cqe->res != 4096) {
+			if (cqe->res == -EOPNOTSUPP)
+				goto skipped;
+			goto err;
+		}
+		io_uring_cqe_seen(&ring, cqe);
+		offset += 4096;
+	} while (--blocks);
+		
+	close(fd);
+	unlink(buf);
+	return 0;
+err:
+	close(fd);
+	unlink(buf);
+	return 1;
+skipped:
+	fprintf(stderr, "Polling not supported in current dir, test skipped\n");
+	close(fd);
+	unlink(buf);
+	return 0;
+}
diff --git a/test/7ad0e4b2f83c-test.c b/test/7ad0e4b2f83c-test.c
new file mode 100644
index 0000000..4d760e1
--- /dev/null
+++ b/test/7ad0e4b2f83c-test.c
@@ -0,0 +1,93 @@
+/* SPDX-License-Identifier: MIT */
+#include <stdio.h>
+#include <time.h>
+#include <sys/time.h>
+#include "liburing.h"
+
+static unsigned long long mtime_since(const struct timeval *s,
+				      const struct timeval *e)
+{
+	long long sec, usec;
+
+	sec = e->tv_sec - s->tv_sec;
+	usec = (e->tv_usec - s->tv_usec);
+	if (sec > 0 && usec < 0) {
+		sec--;
+		usec += 1000000;
+	}
+
+	sec *= 1000;
+	usec /= 1000;
+	return sec + usec;
+}
+
+static unsigned long long mtime_since_now(struct timeval *tv)
+{
+	struct timeval end;
+
+	gettimeofday(&end, NULL);
+	return mtime_since(tv, &end);
+}
+
+int main(int argc, char *argv[])
+{
+	struct __kernel_timespec ts1, ts2;
+	struct io_uring_cqe *cqe;
+	struct io_uring_sqe *sqe;
+	struct io_uring ring;
+	unsigned long msec;
+	struct timeval tv;
+	int ret;
+
+	if (argc > 1)
+		return 0;
+
+	ret = io_uring_queue_init(32, &ring, 0);
+	if (ret) {
+		fprintf(stderr, "io_uring_queue_init=%d\n", ret);
+		return 1;
+	}
+
+	sqe = io_uring_get_sqe(&ring);
+	io_uring_prep_nop(sqe);
+	ret = io_uring_submit(&ring);
+	if (ret != 1) {
+		fprintf(stderr, "io_uring_submit1=%d\n", ret);
+		return 1;
+	}
+
+
+	ts1.tv_sec = 5,
+	ts1.tv_nsec = 0;
+	ret = io_uring_wait_cqe_timeout(&ring, &cqe, &ts1);
+	if (ret) {
+		fprintf(stderr, "io_uring_wait_cqe_timeout=%d\n", ret);
+		return 1;
+	}
+	io_uring_cqe_seen(&ring, cqe);
+	gettimeofday(&tv, NULL);
+
+	ts2.tv_sec = 1;
+	ts2.tv_nsec = 0;
+	sqe = io_uring_get_sqe(&ring);
+	io_uring_prep_timeout(sqe, &ts2, 0, 0);
+	sqe->user_data = 89;
+	ret = io_uring_submit(&ring);
+	if (ret != 1) {
+		fprintf(stderr, "io_uring_submit2=%d\n", ret);
+		return 1;
+	}
+
+	io_uring_wait_cqe(&ring, &cqe);
+	io_uring_cqe_seen(&ring, cqe);
+	msec = mtime_since_now(&tv);
+	if (msec >= 900 && msec <= 1100) {
+		io_uring_queue_exit(&ring);
+		return 0;
+	}
+
+	fprintf(stderr, "%s: Timeout seems wonky (got %lu)\n", __FUNCTION__,
+								msec);
+	io_uring_queue_exit(&ring);
+	return 1;
+}
diff --git a/test/8a9973408177-test.c b/test/8a9973408177-test.c
new file mode 100644
index 0000000..94bf781
--- /dev/null
+++ b/test/8a9973408177-test.c
@@ -0,0 +1,106 @@
+/* SPDX-License-Identifier: MIT */
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+
+#include "liburing.h"
+
+static int register_file(struct io_uring *ring)
+{
+	char buf[32];
+	int ret, fd;
+
+	sprintf(buf, "./XXXXXX");
+	fd = mkstemp(buf);
+	if (fd < 0) {
+		perror("open");
+		return 1;
+	}
+
+	ret = io_uring_register_files(ring, &fd, 1);
+	if (ret) {
+		fprintf(stderr, "file register %d\n", ret);
+		return 1;
+	}
+
+	ret = io_uring_unregister_files(ring);
+	if (ret) {
+		fprintf(stderr, "file register %d\n", ret);
+		return 1;
+	}
+
+	unlink(buf);
+	close(fd);
+	return 0;
+}
+
+static int test_single_fsync(struct io_uring *ring)
+{
+	struct io_uring_cqe *cqe;
+	struct io_uring_sqe *sqe;
+	char buf[32];
+	int fd, ret;
+
+	sprintf(buf, "./XXXXXX");
+	fd = mkstemp(buf);
+	if (fd < 0) {
+		perror("open");
+		return 1;
+	}
+
+	sqe = io_uring_get_sqe(ring);
+	if (!sqe) {
+		printf("get sqe failed\n");
+		goto err;
+	}
+
+	io_uring_prep_fsync(sqe, fd, 0);
+
+	ret = io_uring_submit(ring);
+	if (ret <= 0) {
+		printf("sqe submit failed: %d\n", ret);
+		goto err;
+	}
+
+	ret = io_uring_wait_cqe(ring, &cqe);
+	if (ret < 0) {
+		printf("wait completion %d\n", ret);
+		goto err;
+	}
+
+	io_uring_cqe_seen(ring, cqe);
+	unlink(buf);
+	return 0;
+err:
+	unlink(buf);
+	return 1;
+}
+
+int main(int argc, char *argv[])
+{
+	struct io_uring ring;
+	int ret;
+
+	if (argc > 1)
+		return 0;
+
+	ret = io_uring_queue_init(8, &ring, 0);
+	if (ret) {
+		printf("ring setup failed\n");
+		return 1;
+	}
+
+	ret = register_file(&ring);
+	if (ret)
+		return ret;
+	ret = test_single_fsync(&ring);
+	if (ret) {
+		printf("test_single_fsync failed\n");
+		return ret;
+	}
+
+	return 0;
+}
diff --git a/test/917257daa0fe-test.c b/test/917257daa0fe-test.c
new file mode 100644
index 0000000..1d00ef1
--- /dev/null
+++ b/test/917257daa0fe-test.c
@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: MIT */
+// autogenerated by syzkaller (https://github.com/google/syzkaller)
+
+#include <endian.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+#include "liburing.h"
+#include "../src/syscall.h"
+
+int main(int argc, char *argv[])
+{
+  if (argc > 1)
+    return 0;
+
+  mmap((void *) 0x20000000, 0x1000000, 3, 0x32, -1, 0);
+
+  *(uint32_t*)0x20000000 = 0;
+  *(uint32_t*)0x20000004 = 0;
+  *(uint32_t*)0x20000008 = 6;
+  *(uint32_t*)0x2000000c = 0;
+  *(uint32_t*)0x20000010 = 0x3af;
+  *(uint32_t*)0x20000014 = 0;
+  *(uint32_t*)0x20000018 = 0;
+  *(uint32_t*)0x2000001c = 0;
+  *(uint32_t*)0x20000020 = 0;
+  *(uint32_t*)0x20000024 = 0;
+  *(uint32_t*)0x20000028 = 0;
+  *(uint32_t*)0x2000002c = 0;
+  *(uint32_t*)0x20000030 = 0;
+  *(uint32_t*)0x20000034 = 0;
+  *(uint32_t*)0x20000038 = 0;
+  *(uint32_t*)0x2000003c = 0;
+  *(uint32_t*)0x20000040 = 0;
+  *(uint32_t*)0x20000044 = 0;
+  *(uint64_t*)0x20000048 = 0;
+  *(uint32_t*)0x20000050 = 0;
+  *(uint32_t*)0x20000054 = 0;
+  *(uint32_t*)0x20000058 = 0;
+  *(uint32_t*)0x2000005c = 0;
+  *(uint32_t*)0x20000060 = 0;
+  *(uint32_t*)0x20000064 = 0;
+  *(uint32_t*)0x20000068 = 0;
+  *(uint32_t*)0x2000006c = 0;
+  *(uint64_t*)0x20000070 = 0;
+  __sys_io_uring_setup(0x7a6, (struct io_uring_params *) 0x20000000UL);
+  return 0;
+}
diff --git a/test/Makefile b/test/Makefile
new file mode 100644
index 0000000..2f0a694
--- /dev/null
+++ b/test/Makefile
@@ -0,0 +1,296 @@
+prefix ?= /usr
+datadir ?= $(prefix)/share
+
+INSTALL=install
+
+CPPFLAGS ?=
+override CPPFLAGS += -D_GNU_SOURCE -D__SANE_USERSPACE_TYPES__ \
+	-I../src/include/ -include ../config-host.h
+CFLAGS ?= -g -O2
+XCFLAGS =
+override CFLAGS += -Wall -Wextra -Wno-unused-parameter -Wno-sign-compare \
+	-L../src/
+CXXFLAGS ?=
+override CXXFLAGS += $(CFLAGS) -std=c++11
+
+test_targets += \
+	232c93d07b74-test \
+	35fa71a030ca-test \
+	500f9fbadef8-test \
+	7ad0e4b2f83c-test \
+	8a9973408177-test \
+	917257daa0fe-test \
+	a0908ae19763-test \
+	a4c0b3decb33-test \
+	accept \
+	accept-link \
+	accept-reuse \
+	accept-test \
+	across-fork splice \
+	b19062a56726-test \
+	b5837bd5311d-test \
+	ce593a6c480a-test \
+	close-opath \
+	connect \
+	cq-full \
+	cq-overflow \
+	cq-peek-batch \
+	cq-ready \
+	cq-size \
+	d4ae271dfaae-test \
+	d77a67ed5f27-test \
+	defer \
+	double-poll-crash \
+	eeed8b54e0df-test \
+	eventfd \
+	eventfd-disable \
+	eventfd-ring \
+	fadvise \
+	fallocate \
+	fc2a85cb02ef-test \
+	file-register \
+	file-update \
+	files-exit-hang-poll \
+	files-exit-hang-timeout \
+	fixed-link \
+	fsync \
+	hardlink \
+	io-cancel \
+	io_uring_enter \
+	io_uring_register \
+	io_uring_setup \
+	iopoll \
+	lfs-openat \
+	lfs-openat-write \
+	link \
+	link-timeout \
+	link_drain \
+	madvise \
+	mkdir \
+	multicqes_drain \
+	nop \
+	nop-all-sizes \
+	open-close \
+	openat2 \
+	personality \
+	pipe-eof \
+	pipe-reuse \
+	poll \
+	poll-cancel \
+	poll-cancel-ton \
+	poll-link \
+	poll-many \
+	poll-mshot-update \
+	poll-ring \
+	poll-v-poll \
+	probe \
+	read-write \
+	register-restrictions \
+	rename \
+	ring-leak \
+	ring-leak2 \
+	rw_merge_test \
+	self \
+	send_recv \
+	send_recvmsg \
+	shared-wq \
+	short-read \
+	shutdown \
+	sigfd-deadlock \
+	socket-rw \
+	socket-rw-eagain \
+	sq-full \
+	sq-poll-dup \
+	sq-poll-kthread \
+	sq-poll-share \
+	sqpoll-disable-exit \
+	sqpoll-exit-hang \
+	sqpoll-sleep \
+	sq-space_left \
+	stdout \
+	submit-reuse \
+	symlink \
+	teardowns \
+	thread-exit \
+	timeout \
+	timeout-new \
+	timeout-overflow \
+	unlink \
+	wakeup-hang \
+	sendmsg_fs_cve \
+	rsrc_tags \
+	# EOL
+
+all_targets += $(test_targets)
+
+include ../Makefile.quiet
+
+ifneq ($(MAKECMDGOALS),clean)
+include ../config-host.mak
+endif
+
+ifdef CONFIG_HAVE_STATX
+test_targets += statx
+endif
+all_targets += statx
+
+ifdef CONFIG_HAVE_CXX
+test_targets += sq-full-cpp
+endif
+all_targets += sq-full-cpp
+
+helpers = helpers.o
+
+all: ${helpers} $(test_targets)
+
+helpers.o: helpers.c helpers.c
+	$(QUIET_CC)$(CC) $(CPPFLAGS) $(CFLAGS) -o $@ -c $< -luring
+
+%: %.c ${helpers} helpers.h
+	$(QUIET_CC)$(CC) $(CPPFLAGS) $(CFLAGS) -o $@ $< ${helpers} -luring $(XCFLAGS)
+
+%: %.cc ${helpers} helpers.h
+	$(QUIET_CXX)$(CXX) $(CPPFLAGS) $(CXXFLAGS) -o $@ $< ${helpers} -luring $(XCFLAGS)
+
+test_srcs := \
+	helpers.c \
+	232c93d07b74-test.c \
+	35fa71a030ca-test.c \
+	500f9fbadef8-test.c \
+	7ad0e4b2f83c-test.c \
+	8a9973408177-test.c \
+	917257daa0fe-test.c \
+	a0908ae19763-test.c \
+	a4c0b3decb33-test.c \
+	accept-link.c \
+	accept-reuse.c \
+	accept-test.c \
+	accept.c \
+	across-fork.c \
+	b19062a56726-test.c \
+	b5837bd5311d-test.c \
+	ce593a6c480a-test.c \
+	close-opath.c \
+	connect.c \
+	cq-full.c \
+	cq-overflow.c \
+	cq-peek-batch.c \
+	cq-ready.c\
+	cq-size.c \
+	d4ae271dfaae-test.c \
+	d77a67ed5f27-test.c \
+	defer.c \
+	double-poll-crash.c \
+	eeed8b54e0df-test.c \
+	eventfd-disable.c \
+	eventfd-ring.c \
+	eventfd.c \
+	fadvise.c \
+	fallocate.c \
+	fc2a85cb02ef-test.c \
+	file-register.c \
+	file-update.c \
+	files-exit-hang-poll.c \
+	files-exit-hang-timeout.c \
+	fixed-link.c \
+	fsync.c \
+	hardlink.c \
+	io-cancel.c \
+	io_uring_enter.c \
+	io_uring_register.c \
+	io_uring_setup.c \
+	iopoll.c \
+	lfs-openat-write.c \
+	lfs-openat.c \
+	link-timeout.c \
+	link.c \
+	link_drain.c \
+	madvise.c \
+	mkdir.c \
+	multicqes_drain.c \
+	nop-all-sizes.c \
+	nop.c \
+	open-close.c \
+	openat2.c \
+	personality.c \
+	pipe-eof.c \
+	pipe-reuse.c \
+	poll-cancel-ton.c \
+	poll-cancel.c \
+	poll-link.c \
+	poll-many.c \
+	poll-mshot-update.c \
+	poll-ring.c \
+	poll-v-poll.c \
+	poll.c \
+	probe.c \
+	read-write.c \
+	register-restrictions.c \
+	rename.c \
+	ring-leak.c \
+	ring-leak2.c \
+	rw_merge_test.c \
+	self.c \
+	send_recvmsg.c \
+	shared-wq.c \
+	short-read.c \
+	shutdown.c \
+	sigfd-deadlock.c \
+	socket-rw.c \
+	socket-rw-eagain.c \
+	splice.c \
+	sq-full-cpp.cc \
+	sq-full.c \
+	sq-poll-dup.c \
+	sq-poll-kthread.c \
+	sq-poll-share.c \
+	sqpoll-disable-exit.c \
+	sqpoll-exit-hang.c \
+	sqpoll-sleep.c \
+	sq-space_left.c \
+	statx.c \
+	stdout.c \
+	submit-reuse.c \
+	symlink.c \
+	teardowns.c \
+	thread-exit.c \
+	timeout-new.c \
+	timeout-overflow.c \
+	timeout.c \
+	unlink.c \
+	wakeup-hang.c \
+	sendmsg_fs_cve.c \
+	rsrc_tags.c \
+	# EOL
+
+test_objs := $(patsubst %.c,%.ol,$(patsubst %.cc,%.ol,$(test_srcs)))
+
+35fa71a030ca-test: XCFLAGS = -lpthread
+232c93d07b74-test: XCFLAGS = -lpthread
+send_recv: XCFLAGS = -lpthread
+send_recvmsg: XCFLAGS = -lpthread
+poll-link: XCFLAGS = -lpthread
+accept-link: XCFLAGS = -lpthread
+submit-reuse: XCFLAGS = -lpthread
+poll-v-poll: XCFLAGS = -lpthread
+across-fork: XCFLAGS = -lpthread
+ce593a6c480a-test: XCFLAGS = -lpthread
+wakeup-hang: XCFLAGS = -lpthread
+pipe-eof: XCFLAGS = -lpthread
+timeout-new: XCFLAGS = -lpthread
+thread-exit: XCFLAGS = -lpthread
+ring-leak2: XCFLAGS = -lpthread
+poll-mshot-update: XCFLAGS = -lpthread
+
+install: $(test_targets) runtests.sh runtests-loop.sh
+	$(INSTALL) -D -d -m 755 $(datadir)/liburing-test/
+	$(INSTALL) -D -m 755 $(test_targets) $(datadir)/liburing-test/
+	$(INSTALL) -D -m 755 runtests.sh  $(datadir)/liburing-test/
+	$(INSTALL) -D -m 755 runtests-loop.sh  $(datadir)/liburing-test/
+clean:
+	@rm -f $(all_targets) $(test_objs) helpers.o
+
+runtests: all
+	@./runtests.sh $(test_targets)
+runtests-loop: all
+	@./runtests-loop.sh $(test_targets)
diff --git a/test/a0908ae19763-test.c b/test/a0908ae19763-test.c
new file mode 100644
index 0000000..00cb559
--- /dev/null
+++ b/test/a0908ae19763-test.c
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: MIT */
+// autogenerated by syzkaller (https://github.com/google/syzkaller)
+
+#include <endian.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+#include "liburing.h"
+#include "../src/syscall.h"
+
+uint64_t r[1] = {0xffffffffffffffff};
+
+int main(int argc, char *argv[])
+{
+  if (argc > 1)
+    return 0;
+  mmap((void *) 0x20000000, 0x1000000, 3, 0x32, -1, 0);
+  intptr_t res = 0;
+  *(uint32_t*)0x20000080 = 0;
+  *(uint32_t*)0x20000084 = 0;
+  *(uint32_t*)0x20000088 = 0;
+  *(uint32_t*)0x2000008c = 0;
+  *(uint32_t*)0x20000090 = 0;
+  *(uint32_t*)0x20000094 = 0;
+  *(uint32_t*)0x20000098 = 0;
+  *(uint32_t*)0x2000009c = 0;
+  *(uint32_t*)0x200000a0 = 0;
+  *(uint32_t*)0x200000a4 = 0;
+  *(uint32_t*)0x200000a8 = 0;
+  *(uint32_t*)0x200000ac = 0;
+  *(uint32_t*)0x200000b0 = 0;
+  *(uint32_t*)0x200000b4 = 0;
+  *(uint32_t*)0x200000b8 = 0;
+  *(uint32_t*)0x200000bc = 0;
+  *(uint32_t*)0x200000c0 = 0;
+  *(uint32_t*)0x200000c4 = 0;
+  *(uint64_t*)0x200000c8 = 0;
+  *(uint32_t*)0x200000d0 = 0;
+  *(uint32_t*)0x200000d4 = 0;
+  *(uint32_t*)0x200000d8 = 0;
+  *(uint32_t*)0x200000dc = 0;
+  *(uint32_t*)0x200000e0 = 0;
+  *(uint32_t*)0x200000e4 = 0;
+  *(uint32_t*)0x200000e8 = 0;
+  *(uint32_t*)0x200000ec = 0;
+  *(uint64_t*)0x200000f0 = 0;
+  res = __sys_io_uring_setup(0xa4, (struct io_uring_params *) 0x20000080);
+  if (res != -1)
+    r[0] = res;
+  *(uint32_t*)0x20000280 = -1;
+  __sys_io_uring_register(r[0], 2, (const void *) 0x20000280, 1);
+  return 0;
+}
diff --git a/test/a4c0b3decb33-test.c b/test/a4c0b3decb33-test.c
new file mode 100644
index 0000000..34b0af2
--- /dev/null
+++ b/test/a4c0b3decb33-test.c
@@ -0,0 +1,180 @@
+/* SPDX-License-Identifier: MIT */
+// autogenerated by syzkaller (https://github.com/google/syzkaller)
+
+#include <dirent.h>
+#include <endian.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/prctl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/mman.h>
+#include <time.h>
+#include <unistd.h>
+
+#include "liburing.h"
+#include "../src/syscall.h"
+
+static void sleep_ms(uint64_t ms)
+{
+	usleep(ms * 1000);
+}
+
+static uint64_t current_time_ms(void)
+{
+	struct timespec ts;
+	if (clock_gettime(CLOCK_MONOTONIC, &ts))
+		exit(1);
+	return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000;
+}
+
+static bool write_file(const char* file, const char* what, ...)
+{
+	char buf[1024];
+	va_list args;
+	va_start(args, what);
+	vsnprintf(buf, sizeof(buf), what, args);
+	va_end(args);
+	buf[sizeof(buf) - 1] = 0;
+	int len = strlen(buf);
+	int fd = open(file, O_WRONLY | O_CLOEXEC);
+	if (fd == -1)
+		return false;
+	if (write(fd, buf, len) != len) {
+		int err = errno;
+		close(fd);
+		errno = err;
+		return false;
+	}
+	close(fd);
+	return true;
+}
+
+static void kill_and_wait(int pid, int* status)
+{
+	kill(-pid, SIGKILL);
+	kill(pid, SIGKILL);
+	int i;
+	for (i = 0; i < 100; i++) {
+		if (waitpid(-1, status, WNOHANG | __WALL) == pid)
+			return;
+		usleep(1000);
+	}
+	DIR* dir = opendir("/sys/fs/fuse/connections");
+	if (dir) {
+		for (;;) {
+			struct dirent* ent = readdir(dir);
+			if (!ent)
+				break;
+			if (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0)
+				continue;
+			char abort[300];
+			snprintf(abort, sizeof(abort), "/sys/fs/fuse/connections/%s/abort",
+					ent->d_name);
+			int fd = open(abort, O_WRONLY);
+			if (fd == -1) {
+				continue;
+			}
+			if (write(fd, abort, 1) < 0) {
+			}
+			close(fd);
+		}
+		closedir(dir);
+	} else {
+	}
+	while (waitpid(-1, status, __WALL) != pid) {
+	}
+}
+
+static void setup_test()
+{
+	prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
+	setpgrp();
+	write_file("/proc/self/oom_score_adj", "1000");
+}
+
+static void execute_one(void);
+
+#define WAIT_FLAGS __WALL
+
+static void loop(void)
+{
+	int iter;
+	for (iter = 0; iter < 5000; iter++) {
+		int pid = fork();
+		if (pid < 0)
+			exit(1);
+		if (pid == 0) {
+			setup_test();
+			execute_one();
+			exit(0);
+		}
+		int status = 0;
+		uint64_t start = current_time_ms();
+		for (;;) {
+			if (waitpid(-1, &status, WNOHANG | WAIT_FLAGS) == pid)
+				break;
+			sleep_ms(1);
+			if (current_time_ms() - start < 5 * 1000)
+				continue;
+			kill_and_wait(pid, &status);
+			break;
+		}
+	}
+}
+
+void execute_one(void)
+{
+	*(uint32_t*)0x20000080 = 0;
+	*(uint32_t*)0x20000084 = 0;
+	*(uint32_t*)0x20000088 = 3;
+	*(uint32_t*)0x2000008c = 3;
+	*(uint32_t*)0x20000090 = 0x175;
+	*(uint32_t*)0x20000094 = 0;
+	*(uint32_t*)0x20000098 = 0;
+	*(uint32_t*)0x2000009c = 0;
+	*(uint32_t*)0x200000a0 = 0;
+	*(uint32_t*)0x200000a4 = 0;
+	*(uint32_t*)0x200000a8 = 0;
+	*(uint32_t*)0x200000ac = 0;
+	*(uint32_t*)0x200000b0 = 0;
+	*(uint32_t*)0x200000b4 = 0;
+	*(uint32_t*)0x200000b8 = 0;
+	*(uint32_t*)0x200000bc = 0;
+	*(uint32_t*)0x200000c0 = 0;
+	*(uint32_t*)0x200000c4 = 0;
+	*(uint64_t*)0x200000c8 = 0;
+	*(uint32_t*)0x200000d0 = 0;
+	*(uint32_t*)0x200000d4 = 0;
+	*(uint32_t*)0x200000d8 = 0;
+	*(uint32_t*)0x200000dc = 0;
+	*(uint32_t*)0x200000e0 = 0;
+	*(uint32_t*)0x200000e4 = 0;
+	*(uint32_t*)0x200000e8 = 0;
+	*(uint32_t*)0x200000ec = 0;
+	*(uint64_t*)0x200000f0 = 0;
+	__sys_io_uring_setup(0x983, (struct io_uring_params *) 0x20000080);
+}
+
+static void sig_int(int sig)
+{
+	exit(0);
+}
+
+int main(int argc, char *argv[])
+{
+	if (argc > 1)
+		return 0;
+	signal(SIGINT, sig_int);
+	mmap((void *) 0x20000000, 0x1000000, 3, 0x32, -1, 0);
+	loop();
+	return 0;
+}
diff --git a/test/accept-link.c b/test/accept-link.c
new file mode 100644
index 0000000..605e0ec
--- /dev/null
+++ b/test/accept-link.c
@@ -0,0 +1,251 @@
+/* SPDX-License-Identifier: MIT */
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <assert.h>
+#include <pthread.h>
+#include <sys/socket.h>
+#include <netinet/tcp.h>
+#include <netinet/in.h>
+#include <poll.h>
+
+#include "liburing.h"
+
+pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
+pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
+
+static int recv_thread_ready = 0;
+static int recv_thread_done = 0;
+
+static void signal_var(int *var)
+{
+        pthread_mutex_lock(&mutex);
+        *var = 1;
+        pthread_cond_signal(&cond);
+        pthread_mutex_unlock(&mutex);
+}
+
+static void wait_for_var(int *var)
+{
+        pthread_mutex_lock(&mutex);
+
+        while (!*var)
+                pthread_cond_wait(&cond, &mutex);
+
+        pthread_mutex_unlock(&mutex);
+}
+
+struct data {
+	unsigned expected[2];
+	unsigned just_positive[2];
+	unsigned long timeout;
+	int port;
+	int stop;
+};
+
+static void *send_thread(void *arg)
+{
+	struct data *data = arg;
+	int ret;
+
+	wait_for_var(&recv_thread_ready);
+
+	if (data->stop)
+		return NULL;
+
+	int s0 = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+	assert(s0 != -1);
+
+	struct sockaddr_in addr;
+
+	addr.sin_family = AF_INET;
+	addr.sin_port = data->port;
+	addr.sin_addr.s_addr = 0x0100007fU;
+
+	ret = connect(s0, (struct sockaddr*)&addr, sizeof(addr));
+	assert(ret != -1);
+
+	wait_for_var(&recv_thread_done);
+
+	close(s0);
+	return NULL;
+}
+
+void *recv_thread(void *arg)
+{
+	struct data *data = arg;
+	struct io_uring ring;
+	int i, ret;
+
+	ret = io_uring_queue_init(8, &ring, 0);
+	assert(ret == 0);
+
+	int s0 = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+	assert(s0 != -1);
+
+	int32_t val = 1;
+	ret = setsockopt(s0, SOL_SOCKET, SO_REUSEPORT, &val, sizeof(val));
+	assert(ret != -1);
+	ret = setsockopt(s0, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
+	assert(ret != -1);
+
+	struct sockaddr_in addr;
+
+	addr.sin_family = AF_INET;
+	addr.sin_addr.s_addr = 0x0100007fU;
+
+	i = 0;
+	do {
+		data->port = 1025 + (rand() % 64510);
+		addr.sin_port = data->port;
+
+		if (bind(s0, (struct sockaddr*)&addr, sizeof(addr)) != -1)
+			break;
+	} while (++i < 100);
+
+	if (i >= 100) {
+		printf("Can't find good port, skipped\n");
+		data->stop = 1;
+		signal_var(&recv_thread_ready);
+		goto out;
+	}
+
+	ret = listen(s0, 128);
+	assert(ret != -1);
+
+	signal_var(&recv_thread_ready);
+
+	struct io_uring_sqe *sqe;
+
+	sqe = io_uring_get_sqe(&ring);
+	assert(sqe != NULL);
+
+	io_uring_prep_accept(sqe, s0, NULL, NULL, 0);
+	sqe->flags |= IOSQE_IO_LINK;
+	sqe->user_data = 1;
+
+	sqe = io_uring_get_sqe(&ring);
+	assert(sqe != NULL);
+
+	struct __kernel_timespec ts;
+	ts.tv_sec = data->timeout / 1000000000;
+	ts.tv_nsec = data->timeout % 1000000000;
+	io_uring_prep_link_timeout(sqe, &ts, 0);
+	sqe->user_data = 2;
+
+	ret = io_uring_submit(&ring);
+	assert(ret == 2);
+
+	for (i = 0; i < 2; i++) {
+		struct io_uring_cqe *cqe;
+		int idx;
+
+		if (io_uring_wait_cqe(&ring, &cqe)) {
+			fprintf(stderr, "wait cqe failed\n");
+			goto err;
+		}
+		idx = cqe->user_data - 1;
+		if (cqe->res != data->expected[idx]) {
+			if (cqe->res > 0 && data->just_positive[idx])
+				goto ok;
+			if (cqe->res == -EBADF) {
+				fprintf(stdout, "Accept not supported, skipping\n");
+				data->stop = 1;
+				goto out;
+			}
+			fprintf(stderr, "cqe %" PRIu64 " got %d, wanted %d\n",
+					(uint64_t) cqe->user_data, cqe->res,
+					data->expected[idx]);
+			goto err;
+		}
+ok:
+		if (cqe->user_data == 1 && cqe->res > 0)
+			close(cqe->res);
+
+		io_uring_cqe_seen(&ring, cqe);
+	}
+
+	signal_var(&recv_thread_done);
+
+out:
+	close(s0);
+	return NULL;
+err:
+	close(s0);
+	return (void *) 1;
+}
+
+static int test_accept_timeout(int do_connect, unsigned long timeout)
+{
+	struct io_uring ring;
+	struct io_uring_params p = {};
+	pthread_t t1, t2;
+	struct data d;
+	void *tret;
+	int ret, fast_poll;
+
+	ret = io_uring_queue_init_params(1, &ring, &p);
+	if (ret) {
+		fprintf(stderr, "queue_init: %d\n", ret);
+		return 1;
+	};
+
+	fast_poll = (p.features & IORING_FEAT_FAST_POLL) != 0;
+	io_uring_queue_exit(&ring);
+
+	recv_thread_ready = 0;
+	recv_thread_done = 0;
+
+	memset(&d, 0, sizeof(d));
+	d.timeout = timeout;
+	if (!do_connect) {
+		if (fast_poll) {
+			d.expected[0] = -ECANCELED;
+			d.expected[1] = -ETIME;
+		} else {
+			d.expected[0] = -EINTR;
+			d.expected[1] = -EALREADY;
+		}
+	} else {
+		d.expected[0] = -1U;
+		d.just_positive[0] = 1;
+		d.expected[1] = -ECANCELED;
+	}
+
+	pthread_create(&t1, NULL, recv_thread, &d);
+
+	if (do_connect)
+		pthread_create(&t2, NULL, send_thread, &d);
+
+	pthread_join(t1, &tret);
+	if (tret)
+		ret++;
+
+	if (do_connect) {
+		pthread_join(t2, &tret);
+		if (tret)
+			ret++;
+	}
+
+	return ret;
+}
+
+int main(int argc, char *argv[])
+{
+	if (argc > 1)
+		return 0;
+	if (test_accept_timeout(0, 200000000)) {
+		fprintf(stderr, "accept timeout 0 failed\n");
+		return 1;
+	}
+
+	if (test_accept_timeout(1, 1000000000)) {
+		fprintf(stderr, "accept and connect timeout 0 failed\n");
+		return 1;
+	}
+
+	return 0;
+}
diff --git a/test/accept-reuse.c b/test/accept-reuse.c
new file mode 100644
index 0000000..c95ac70
--- /dev/null
+++ b/test/accept-reuse.c
@@ -0,0 +1,164 @@
+/* SPDX-License-Identifier: MIT */
+#include <liburing.h>
+#include <netdb.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <errno.h>
+#include "liburing.h"
+#include "../src/syscall.h"
+
+struct io_uring io_uring;
+
+int sys_io_uring_enter(const int fd,
+		       const unsigned to_submit,
+		       const unsigned min_complete,
+		       const unsigned flags, sigset_t * const sig)
+{
+	return __sys_io_uring_enter(fd, to_submit, min_complete, flags, sig);
+}
+
+int submit_sqe(void)
+{
+	struct io_uring_sq *sq = &io_uring.sq;
+	const unsigned tail = *sq->ktail;
+
+	sq->array[tail & *sq->kring_mask] = 0;
+	io_uring_smp_store_release(sq->ktail, tail + 1);
+
+	return sys_io_uring_enter(io_uring.ring_fd, 1, 0, 0, NULL);
+}
+
+int main(int argc, char **argv)
+{
+	struct addrinfo *addr_info_list = NULL;
+	struct addrinfo *ai, *addr_info = NULL;
+	struct io_uring_params params;
+	struct io_uring_sqe *sqe;
+	struct addrinfo hints;
+	struct sockaddr sa;
+	socklen_t sa_size = sizeof(sa);
+	int ret, listen_fd, connect_fd, val, i;
+
+	if (argc > 1)
+		return 0;
+
+	memset(&params, 0, sizeof(params));
+	ret = io_uring_queue_init_params(4, &io_uring, &params);
+	if (ret) {
+		fprintf(stderr, "io_uring_init_failed: %d\n", ret);
+		return 1;
+	}
+	if (!(params.features & IORING_FEAT_SUBMIT_STABLE)) {
+		fprintf(stdout, "FEAT_SUBMIT_STABLE not there, skipping\n");
+		return 0;
+	}
+
+	memset(&hints, 0, sizeof(hints));
+	hints.ai_family = AF_UNSPEC;
+	hints.ai_socktype = SOCK_STREAM;
+	hints.ai_flags = AI_PASSIVE | AI_NUMERICSERV;
+
+	ret = getaddrinfo(NULL, "12345", &hints, &addr_info_list);
+	if (ret < 0) {
+		perror("getaddrinfo");
+		return 1;
+	}
+
+	for (ai = addr_info_list; ai; ai = ai->ai_next) {
+		if (ai->ai_family == AF_INET || ai->ai_family == AF_INET6) {
+			addr_info = ai;
+			break;
+		}
+	}
+	if (!addr_info) {
+		fprintf(stderr, "addrinfo not found\n");
+		return 1;
+	}
+
+	sqe = &io_uring.sq.sqes[0];
+	listen_fd = -1;
+
+	ret = socket(addr_info->ai_family, SOCK_STREAM,
+			   addr_info->ai_protocol);
+	if (ret < 0) {
+		perror("socket");
+		return 1;
+	}
+	listen_fd = ret;
+
+	val = 1;
+	setsockopt(listen_fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(int));
+	setsockopt(listen_fd, SOL_SOCKET, SO_REUSEPORT, &val, sizeof(int));
+
+	ret = bind(listen_fd, addr_info->ai_addr, addr_info->ai_addrlen);
+	if (ret < 0) {
+		perror("bind");
+		return 1;
+	}
+
+	ret = listen(listen_fd, SOMAXCONN);
+	if (ret < 0) {
+		perror("listen");
+		return 1;
+	}
+
+	memset(&sa, 0, sizeof(sa));
+
+	io_uring_prep_accept(sqe, listen_fd, &sa, &sa_size, 0);
+	sqe->user_data = 1;
+	ret = submit_sqe();
+	if (ret != 1) {
+		fprintf(stderr, "submit failed: %d\n", ret);
+		return 1;
+	}
+
+	connect_fd = -1;
+	ret = socket(addr_info->ai_family, SOCK_STREAM, addr_info->ai_protocol);
+	if (ret < 0) {
+		perror("socket");
+		return 1;
+	}
+	connect_fd = ret;
+
+	io_uring_prep_connect(sqe, connect_fd, addr_info->ai_addr,
+				addr_info->ai_addrlen);
+	sqe->user_data = 2;
+	ret = submit_sqe();
+	if (ret != 1) {
+		fprintf(stderr, "submit failed: %d\n", ret);
+		return 1;
+	}
+
+	for (i = 0; i < 2; i++) {
+		struct io_uring_cqe *cqe = NULL;
+
+		ret = io_uring_wait_cqe(&io_uring, &cqe);
+		if (ret) {
+			fprintf(stderr, "io_uring_wait_cqe: %d\n", ret);
+			return 1;
+		}
+
+		switch (cqe->user_data) {
+		case 1:
+			if (cqe->res < 0) {
+				fprintf(stderr, "accept failed: %d\n", cqe->res);
+				return 1;
+			}
+			break;
+		case 2:
+			if (cqe->res) {
+				fprintf(stderr, "connect failed: %d\n", cqe->res);
+				return 1;
+			}
+			break;
+		}
+		io_uring_cq_advance(&io_uring, 1);
+	}
+
+	freeaddrinfo(addr_info_list);
+	io_uring_queue_exit(&io_uring);
+	return 0;
+}
diff --git a/test/accept-test.c b/test/accept-test.c
new file mode 100644
index 0000000..71d9d80
--- /dev/null
+++ b/test/accept-test.c
@@ -0,0 +1,79 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: Check to see if accept handles addr and addrlen
+ */
+#include <stdio.h>
+#include <errno.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <assert.h>
+#include "liburing.h"
+
+int main(int argc, char *argv[])
+{
+	struct io_uring_sqe *sqe;
+	struct io_uring_cqe *cqe;
+	struct io_uring ring;
+	struct sockaddr_un addr;
+	socklen_t addrlen = sizeof(addr);
+	int ret, fd;
+	struct __kernel_timespec ts = {
+		.tv_sec = 0,
+		.tv_nsec = 1000000
+	};
+
+	if (argc > 1)
+		return 0;
+
+	if (io_uring_queue_init(4, &ring, 0) != 0) {
+		fprintf(stderr, "ring setup failed\n");
+		return 1;
+	}
+
+	fd = socket(AF_UNIX, SOCK_STREAM, 0);
+	assert(fd != -1);
+
+	memset(&addr, 0, sizeof(addr));
+	addr.sun_family = AF_UNIX;
+	memcpy(addr.sun_path, "\0sock", 6);
+
+	ret = bind(fd, (struct sockaddr *)&addr, addrlen);
+	assert(ret != -1);
+	ret = listen(fd, 128);
+	assert(ret != -1);
+
+	sqe = io_uring_get_sqe(&ring);
+	if (!sqe) {
+		fprintf(stderr, "get sqe failed\n");
+		return 1;
+	}
+	io_uring_prep_accept(sqe, fd, (struct sockaddr*)&addr, &addrlen, 0);
+	sqe->user_data = 1;
+
+	ret = io_uring_submit(&ring);
+	if (ret != 1) {
+		fprintf(stderr, "Got submit %d, expected 1\n", ret);
+		return 1;
+	}
+
+	ret = io_uring_wait_cqe_timeout(&ring, &cqe, &ts);
+	if (!ret) {
+		if (cqe->res == -EBADF || cqe->res == -EINVAL) {
+			fprintf(stdout, "Accept not supported, skipping\n");
+			goto out;
+		} else if (cqe->res < 0) {
+			fprintf(stderr, "cqe error %d\n", cqe->res);
+			goto err;
+		}
+	} else if (ret != -ETIME) {
+		fprintf(stderr, "accept() failed to use addr & addrlen parameters!\n");
+		return 1;
+	}
+
+out:
+	io_uring_queue_exit(&ring);
+	return 0;
+err:
+	io_uring_queue_exit(&ring);
+	return 1;
+}
diff --git a/test/accept.c b/test/accept.c
new file mode 100644
index 0000000..f096f8a
--- /dev/null
+++ b/test/accept.c
@@ -0,0 +1,437 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Check that IORING_OP_ACCEPT works, and send some data across to verify we
+ * didn't get a junk fd.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <assert.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <sys/un.h>
+#include <netinet/tcp.h>
+#include <netinet/in.h>
+
+#include "helpers.h"
+#include "liburing.h"
+
+static int no_accept;
+
+struct data {
+	char buf[128];
+	struct iovec iov;
+};
+
+static void queue_send(struct io_uring *ring, int fd)
+{
+	struct io_uring_sqe *sqe;
+	struct data *d;
+
+	d = t_malloc(sizeof(*d));
+	d->iov.iov_base = d->buf;
+	d->iov.iov_len = sizeof(d->buf);
+
+	sqe = io_uring_get_sqe(ring);
+	io_uring_prep_writev(sqe, fd, &d->iov, 1, 0);
+}
+
+static void queue_recv(struct io_uring *ring, int fd)
+{
+	struct io_uring_sqe *sqe;
+	struct data *d;
+
+	d = t_malloc(sizeof(*d));
+	d->iov.iov_base = d->buf;
+	d->iov.iov_len = sizeof(d->buf);
+
+	sqe = io_uring_get_sqe(ring);
+	io_uring_prep_readv(sqe, fd, &d->iov, 1, 0);
+}
+
+static int accept_conn(struct io_uring *ring, int fd)
+{
+	struct io_uring_sqe *sqe;
+	struct io_uring_cqe *cqe;
+	int ret;
+
+	sqe = io_uring_get_sqe(ring);
+	io_uring_prep_accept(sqe, fd, NULL, NULL, 0);
+
+	ret = io_uring_submit(ring);
+	assert(ret != -1);
+
+	ret = io_uring_wait_cqe(ring, &cqe);
+	assert(!ret);
+	ret = cqe->res;
+	io_uring_cqe_seen(ring, cqe);
+	return ret;
+}
+
+static int start_accept_listen(struct sockaddr_in *addr, int port_off)
+{
+	int fd, ret;
+
+	fd = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, IPPROTO_TCP);
+
+	int32_t val = 1;
+	ret = setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &val, sizeof(val));
+	assert(ret != -1);
+	ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
+	assert(ret != -1);
+
+	struct sockaddr_in laddr;
+
+	if (!addr)
+		addr = &laddr;
+
+	addr->sin_family = AF_INET;
+	addr->sin_port = 0x1235 + port_off;
+	addr->sin_addr.s_addr = 0x0100007fU;
+
+	ret = bind(fd, (struct sockaddr*)addr, sizeof(*addr));
+	assert(ret != -1);
+	ret = listen(fd, 128);
+	assert(ret != -1);
+
+	return fd;
+}
+
+static int test(struct io_uring *ring, int accept_should_error)
+{
+	struct io_uring_cqe *cqe;
+	struct sockaddr_in addr;
+	uint32_t head;
+	uint32_t count = 0;
+	int done = 0;
+	int p_fd[2];
+        int ret;
+
+	int32_t val, recv_s0 = start_accept_listen(&addr, 0);
+
+	p_fd[1] = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, IPPROTO_TCP);
+
+	val = 1;
+	ret = setsockopt(p_fd[1], IPPROTO_TCP, TCP_NODELAY, &val, sizeof(val));
+	assert(ret != -1);
+
+	int32_t flags = fcntl(p_fd[1], F_GETFL, 0);
+	assert(flags != -1);
+
+	flags |= O_NONBLOCK;
+	ret = fcntl(p_fd[1], F_SETFL, flags);
+	assert(ret != -1);
+
+	ret = connect(p_fd[1], (struct sockaddr*)&addr, sizeof(addr));
+	assert(ret == -1);
+
+	flags = fcntl(p_fd[1], F_GETFL, 0);
+	assert(flags != -1);
+
+	flags &= ~O_NONBLOCK;
+	ret = fcntl(p_fd[1], F_SETFL, flags);
+	assert(ret != -1);
+
+	p_fd[0] = accept_conn(ring, recv_s0);
+	if (p_fd[0] == -EINVAL) {
+		if (accept_should_error)
+			goto out;
+		fprintf(stdout, "Accept not supported, skipping\n");
+		no_accept = 1;
+		goto out;
+	} else if (p_fd[0] < 0) {
+		if (accept_should_error &&
+		    (p_fd[0] == -EBADF || p_fd[0] == -EINVAL))
+			goto out;
+		fprintf(stderr, "Accept got %d\n", p_fd[0]);
+		goto err;
+	}
+
+	queue_send(ring, p_fd[1]);
+	queue_recv(ring, p_fd[0]);
+
+	ret = io_uring_submit_and_wait(ring, 2);
+	assert(ret != -1);
+
+	while (count < 2) {
+		io_uring_for_each_cqe(ring, head, cqe) {
+			if (cqe->res < 0) {
+				fprintf(stderr, "Got cqe res %d\n", cqe->res);
+				done = 1;
+				break;
+			}
+			assert(cqe->res == 128);
+			count++;
+		}
+
+		assert(count <= 2);
+		io_uring_cq_advance(ring, count);
+		if (done)
+			goto err;
+	}
+
+out:
+	close(p_fd[0]);
+	close(p_fd[1]);
+	close(recv_s0);
+	return 0;
+err:
+	close(p_fd[0]);
+	close(p_fd[1]);
+	close(recv_s0);
+	return 1;
+}
+
+static void sig_alrm(int sig)
+{
+	exit(0);
+}
+
+static int test_accept_pending_on_exit(void)
+{
+	struct io_uring m_io_uring;
+	struct io_uring_cqe *cqe;
+	struct io_uring_sqe *sqe;
+	int fd, ret;
+
+	ret = io_uring_queue_init(32, &m_io_uring, 0);
+	assert(ret >= 0);
+
+	fd = start_accept_listen(NULL, 0);
+
+	sqe = io_uring_get_sqe(&m_io_uring);
+	io_uring_prep_accept(sqe, fd, NULL, NULL, 0);
+	ret = io_uring_submit(&m_io_uring);
+	assert(ret != -1);
+
+	signal(SIGALRM, sig_alrm);
+	alarm(1);
+	ret = io_uring_wait_cqe(&m_io_uring, &cqe);
+	assert(!ret);
+	io_uring_cqe_seen(&m_io_uring, cqe);
+
+	io_uring_queue_exit(&m_io_uring);
+	return 0;
+}
+
+/*
+ * Test issue many accepts and see if we handle cancellation on exit
+ */
+static int test_accept_many(unsigned nr, unsigned usecs)
+{
+	struct io_uring m_io_uring;
+	struct io_uring_cqe *cqe;
+	struct io_uring_sqe *sqe;
+	unsigned long cur_lim;
+	struct rlimit rlim;
+	int *fds, i, ret;
+
+	if (getrlimit(RLIMIT_NPROC, &rlim) < 0) {
+		perror("getrlimit");
+		return 1;
+	}
+
+	cur_lim = rlim.rlim_cur;
+	rlim.rlim_cur = nr / 4;
+
+	if (setrlimit(RLIMIT_NPROC, &rlim) < 0) {
+		perror("setrlimit");
+		return 1;
+	}
+
+	ret = io_uring_queue_init(2 * nr, &m_io_uring, 0);
+	assert(ret >= 0);
+
+	fds = t_calloc(nr, sizeof(int));
+
+	for (i = 0; i < nr; i++)
+		fds[i] = start_accept_listen(NULL, i);
+
+	for (i = 0; i < nr; i++) {
+		sqe = io_uring_get_sqe(&m_io_uring);
+		io_uring_prep_accept(sqe, fds[i], NULL, NULL, 0);
+		sqe->user_data = 1 + i;
+		ret = io_uring_submit(&m_io_uring);
+		assert(ret == 1);
+	}
+
+	if (usecs)
+		usleep(usecs);
+
+	for (i = 0; i < nr; i++) {
+		if (io_uring_peek_cqe(&m_io_uring, &cqe))
+			break;
+		if (cqe->res != -ECANCELED) {
+			fprintf(stderr, "Expected cqe to be cancelled\n");
+			goto err;
+		}
+		io_uring_cqe_seen(&m_io_uring, cqe);
+	}
+out:
+	rlim.rlim_cur = cur_lim;
+	if (setrlimit(RLIMIT_NPROC, &rlim) < 0) {
+		perror("setrlimit");
+		return 1;
+	}
+
+	free(fds);
+	io_uring_queue_exit(&m_io_uring);
+	return 0;
+err:
+	ret = 1;
+	goto out;
+}
+
+static int test_accept_cancel(unsigned usecs)
+{
+	struct io_uring m_io_uring;
+	struct io_uring_cqe *cqe;
+	struct io_uring_sqe *sqe;
+	int fd, i, ret;
+
+	ret = io_uring_queue_init(32, &m_io_uring, 0);
+	assert(ret >= 0);
+
+	fd = start_accept_listen(NULL, 0);
+
+	sqe = io_uring_get_sqe(&m_io_uring);
+	io_uring_prep_accept(sqe, fd, NULL, NULL, 0);
+	sqe->user_data = 1;
+        ret = io_uring_submit(&m_io_uring);
+	assert(ret == 1);
+
+	if (usecs)
+		usleep(usecs);
+
+	sqe = io_uring_get_sqe(&m_io_uring);
+	io_uring_prep_cancel(sqe, (void *) 1, 0);
+	sqe->user_data = 2;
+	ret = io_uring_submit(&m_io_uring);
+	assert(ret == 1);
+
+	for (i = 0; i < 2; i++) {
+		ret = io_uring_wait_cqe(&m_io_uring, &cqe);
+		assert(!ret);
+		/*
+		 * Two cases here:
+		 *
+		 * 1) We cancel the accept4() before it got started, we should
+		 *    get '0' for the cancel request and '-ECANCELED' for the
+		 *    accept request.
+		 * 2) We cancel the accept4() after it's already running, we
+		 *    should get '-EALREADY' for the cancel request and
+		 *    '-EINTR' for the accept request.
+		 */
+		if (cqe->user_data == 1) {
+			if (cqe->res != -EINTR && cqe->res != -ECANCELED) {
+				fprintf(stderr, "Cancelled accept got %d\n", cqe->res);
+				goto err;
+			}
+		} else if (cqe->user_data == 2) {
+			if (cqe->res != -EALREADY && cqe->res != 0) {
+				fprintf(stderr, "Cancel got %d\n", cqe->res);
+				goto err;
+			}
+		}
+		io_uring_cqe_seen(&m_io_uring, cqe);
+	}
+
+	io_uring_queue_exit(&m_io_uring);
+	return 0;
+err:
+	io_uring_queue_exit(&m_io_uring);
+	return 1;
+}
+
+static int test_accept(void)
+{
+	struct io_uring m_io_uring;
+	int ret;
+
+	ret = io_uring_queue_init(32, &m_io_uring, 0);
+	assert(ret >= 0);
+	ret = test(&m_io_uring, 0);
+	io_uring_queue_exit(&m_io_uring);
+	return ret;
+}
+
+static int test_accept_sqpoll(void)
+{
+	struct io_uring m_io_uring;
+	struct io_uring_params p = { };
+	int ret, should_fail;
+
+	p.flags = IORING_SETUP_SQPOLL;
+	ret = t_create_ring_params(32, &m_io_uring, &p);
+	if (ret == T_SETUP_SKIP)
+		return 0;
+	else if (ret < 0)
+		return ret;
+
+	should_fail = 1;
+	if (p.features & IORING_FEAT_SQPOLL_NONFIXED)
+		should_fail = 0;
+
+	ret = test(&m_io_uring, should_fail);
+	io_uring_queue_exit(&m_io_uring);
+	return ret;
+}
+
+int main(int argc, char *argv[])
+{
+	int ret;
+
+	if (argc > 1)
+		return 0;
+
+	ret = test_accept();
+	if (ret) {
+		fprintf(stderr, "test_accept failed\n");
+		return ret;
+	}
+	if (no_accept)
+		return 0;
+
+	ret = test_accept_sqpoll();
+	if (ret) {
+		fprintf(stderr, "test_accept_sqpoll failed\n");
+		return ret;
+	}
+
+	ret = test_accept_cancel(0);
+	if (ret) {
+		fprintf(stderr, "test_accept_cancel nodelay failed\n");
+		return ret;
+	}
+
+	ret = test_accept_cancel(10000);
+	if (ret) {
+		fprintf(stderr, "test_accept_cancel delay failed\n");
+		return ret;
+	}
+
+	ret = test_accept_many(128, 0);
+	if (ret) {
+		fprintf(stderr, "test_accept_many failed\n");
+		return ret;
+	}
+
+	ret = test_accept_many(128, 100000);
+	if (ret) {
+		fprintf(stderr, "test_accept_many failed\n");
+		return ret;
+	}
+
+	ret = test_accept_pending_on_exit();
+	if (ret) {
+		fprintf(stderr, "test_accept_pending_on_exit failed\n");
+		return ret;
+	}
+
+	return 0;
+}
diff --git a/test/across-fork.c b/test/across-fork.c
new file mode 100644
index 0000000..009fe52
--- /dev/null
+++ b/test/across-fork.c
@@ -0,0 +1,283 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: test sharing a ring across a fork
+ */
+#include <fcntl.h>
+#include <pthread.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "liburing.h"
+
+
+struct forktestmem
+{
+	struct io_uring ring;
+	pthread_barrier_t barrier;
+	pthread_barrierattr_t barrierattr;
+};
+
+static int open_tempfile(const char *dir, const char *fname)
+{
+	int fd;
+	char buf[32];
+
+	snprintf(buf, sizeof(buf), "%s/%s",
+		 dir, fname);
+	fd = open(buf, O_RDWR | O_CREAT | O_APPEND, S_IRUSR | S_IWUSR);
+	if (fd < 0) {
+		perror("open");
+		exit(1);
+	}
+
+	return fd;
+}
+
+static int submit_write(struct io_uring *ring, int fd, const char *str,
+			int wait)
+{
+	struct io_uring_sqe *sqe;
+	struct iovec iovec;
+	int ret;
+
+	sqe = io_uring_get_sqe(ring);
+	if (!sqe) {
+		fprintf(stderr, "could not get sqe\n");
+		return 1;
+	}
+
+	iovec.iov_base = (char *) str;
+	iovec.iov_len = strlen(str);
+	io_uring_prep_writev(sqe, fd, &iovec, 1, 0);
+	ret = io_uring_submit_and_wait(ring, wait);
+	if (ret < 0) {
+		fprintf(stderr, "submit failed: %s\n", strerror(-ret));
+		return 1;
+	}
+
+	return 0;
+}
+
+static int wait_cqe(struct io_uring *ring, const char *stage)
+{
+	struct io_uring_cqe *cqe;
+	int ret;
+
+	ret = io_uring_wait_cqe(ring, &cqe);
+	if (ret) {
+		fprintf(stderr, "%s wait_cqe failed %d\n", stage, ret);
+		return 1;
+	}
+	if (cqe->res < 0) {
+		fprintf(stderr, "%s cqe failed %d\n", stage, cqe->res);
+		return 1;
+	}
+
+	io_uring_cqe_seen(ring, cqe);
+	return 0;
+}
+
+static int verify_file(const char *tmpdir, const char *fname, const char* expect)
+{
+	int fd;
+	char buf[512];
+	int err = 0;
+
+	memset(buf, 0, sizeof(buf));
+
+	fd = open_tempfile(tmpdir, fname);
+	if (fd < 0)
+		return 1;
+
+	if (read(fd, buf, sizeof(buf) - 1) < 0)
+		return 1;
+
+	if (strcmp(buf, expect) != 0) {
+		fprintf(stderr, "content mismatch for %s\n"
+			"got:\n%s\n"
+			"expected:\n%s\n",
+			fname, buf, expect);
+		err = 1;
+	}
+
+	close(fd);
+	return err;
+}
+
+static void cleanup(const char *tmpdir)
+{
+	char buf[32];
+
+	/* don't check errors, called during partial runs */
+
+	snprintf(buf, sizeof(buf), "%s/%s", tmpdir, "shared");
+	unlink(buf);
+
+	snprintf(buf, sizeof(buf), "%s/%s", tmpdir, "parent1");
+	unlink(buf);
+
+	snprintf(buf, sizeof(buf), "%s/%s", tmpdir, "parent2");
+	unlink(buf);
+
+	snprintf(buf, sizeof(buf), "%s/%s", tmpdir, "child");
+	unlink(buf);
+
+	rmdir(tmpdir);
+}
+
+int main(int argc, char *argv[])
+{
+	struct forktestmem *shmem;
+	char tmpdir[] = "forktmpXXXXXX";
+	int shared_fd;
+	int ret;
+	pid_t p;
+
+	if (argc > 1)
+		return 0;
+
+	shmem = mmap(0, sizeof(struct forktestmem), PROT_READ|PROT_WRITE,
+		   MAP_SHARED | MAP_ANONYMOUS, 0, 0);
+	if (!shmem) {
+		fprintf(stderr, "mmap failed\n");
+		exit(1);
+	}
+
+	pthread_barrierattr_init(&shmem->barrierattr);
+	pthread_barrierattr_setpshared(&shmem->barrierattr, 1);
+	pthread_barrier_init(&shmem->barrier, &shmem->barrierattr, 2);
+
+	ret = io_uring_queue_init(10, &shmem->ring, 0);
+	if (ret < 0) {
+		fprintf(stderr, "queue init failed\n");
+		exit(1);
+	}
+
+	if (mkdtemp(tmpdir) == NULL) {
+		fprintf(stderr, "temp directory creation failed\n");
+		exit(1);
+	}
+
+	shared_fd = open_tempfile(tmpdir, "shared");
+
+	/*
+	 * First do a write before the fork, to test whether child can
+	 * reap that
+	 */
+	if (submit_write(&shmem->ring, shared_fd, "before fork: write shared fd\n", 0))
+		goto errcleanup;
+
+	p = fork();
+	switch (p) {
+	case -1:
+		fprintf(stderr, "fork failed\n");
+		goto errcleanup;
+
+	default: {
+		/* parent */
+		int parent_fd1;
+		int parent_fd2;
+		int wstatus;
+
+		/* wait till fork is started up */
+		pthread_barrier_wait(&shmem->barrier);
+
+		parent_fd1 = open_tempfile(tmpdir, "parent1");
+		parent_fd2 = open_tempfile(tmpdir, "parent2");
+
+		/* do a parent write to the shared fd */
+		if (submit_write(&shmem->ring, shared_fd, "parent: write shared fd\n", 0))
+			goto errcleanup;
+
+		/* do a parent write to an fd where same numbered fd exists in child */
+		if (submit_write(&shmem->ring, parent_fd1, "parent: write parent fd 1\n", 0))
+			goto errcleanup;
+
+		/* do a parent write to an fd where no same numbered fd exists in child */
+		if (submit_write(&shmem->ring, parent_fd2, "parent: write parent fd 2\n", 0))
+			goto errcleanup;
+
+		/* wait to switch read/writ roles with child */
+		pthread_barrier_wait(&shmem->barrier);
+
+		/* now wait for child to exit, to ensure we still can read completion */
+		waitpid(p, &wstatus, 0);
+		if (WEXITSTATUS(wstatus) != 0) {
+			fprintf(stderr, "child failed\n");
+			goto errcleanup;
+		}
+
+		if (wait_cqe(&shmem->ring, "p cqe 1"))
+			goto errcleanup;
+
+		if (wait_cqe(&shmem->ring, "p cqe 2"))
+			goto errcleanup;
+
+		/* check that IO can still be submitted after child exited */
+		if (submit_write(&shmem->ring, shared_fd, "parent: write shared fd after child exit\n", 0))
+			goto errcleanup;
+
+		if (wait_cqe(&shmem->ring, "p cqe 3"))
+			goto errcleanup;
+
+		break;
+	}
+	case 0: {
+		/* child */
+		int child_fd;
+
+		/* wait till fork is started up */
+		pthread_barrier_wait(&shmem->barrier);
+
+		child_fd = open_tempfile(tmpdir, "child");
+
+		if (wait_cqe(&shmem->ring, "c cqe shared"))
+			exit(1);
+
+		if (wait_cqe(&shmem->ring, "c cqe parent 1"))
+			exit(1);
+
+		if (wait_cqe(&shmem->ring, "c cqe parent 2"))
+			exit(1);
+
+		if (wait_cqe(&shmem->ring, "c cqe parent 3"))
+			exit(1);
+
+		/* wait to switch read/writ roles with parent */
+		pthread_barrier_wait(&shmem->barrier);
+
+		if (submit_write(&shmem->ring, child_fd, "child: write child fd\n", 0))
+			exit(1);
+
+		/* ensure both writes have finished before child exits */
+		if (submit_write(&shmem->ring, shared_fd, "child: write shared fd\n", 2))
+			exit(1);
+
+		exit(0);
+	}
+	}
+
+	if (verify_file(tmpdir, "shared",
+			 "before fork: write shared fd\n"
+			 "parent: write shared fd\n"
+			 "child: write shared fd\n"
+			 "parent: write shared fd after child exit\n") ||
+	    verify_file(tmpdir, "parent1", "parent: write parent fd 1\n") ||
+	    verify_file(tmpdir, "parent2", "parent: write parent fd 2\n") ||
+	    verify_file(tmpdir, "child", "child: write child fd\n"))
+		goto errcleanup;
+
+	cleanup(tmpdir);
+	exit(0);
+
+errcleanup:
+	cleanup(tmpdir);
+	exit(1);
+}
diff --git a/test/b19062a56726-test.c b/test/b19062a56726-test.c
new file mode 100644
index 0000000..6a0f686
--- /dev/null
+++ b/test/b19062a56726-test.c
@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: MIT */
+// autogenerated by syzkaller (https://github.com/google/syzkaller)
+
+#include <endian.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+#include "liburing.h"
+#include "../src/syscall.h"
+
+int main(int argc, char *argv[])
+{
+  if (argc > 1)
+    return 0;
+
+  mmap((void *) 0x20000000, 0x1000000, 3, 0x32, -1, 0);
+
+  *(uint32_t*)0x20000200 = 0;
+  *(uint32_t*)0x20000204 = 0;
+  *(uint32_t*)0x20000208 = 5;
+  *(uint32_t*)0x2000020c = 0x400;
+  *(uint32_t*)0x20000210 = 0;
+  *(uint32_t*)0x20000214 = 0;
+  *(uint32_t*)0x20000218 = 0;
+  *(uint32_t*)0x2000021c = 0;
+  *(uint32_t*)0x20000220 = 0;
+  *(uint32_t*)0x20000224 = 0;
+  *(uint32_t*)0x20000228 = 0;
+  *(uint32_t*)0x2000022c = 0;
+  *(uint32_t*)0x20000230 = 0;
+  *(uint32_t*)0x20000234 = 0;
+  *(uint32_t*)0x20000238 = 0;
+  *(uint32_t*)0x2000023c = 0;
+  *(uint32_t*)0x20000240 = 0;
+  *(uint32_t*)0x20000244 = 0;
+  *(uint64_t*)0x20000248 = 0;
+  *(uint32_t*)0x20000250 = 0;
+  *(uint32_t*)0x20000254 = 0;
+  *(uint32_t*)0x20000258 = 0;
+  *(uint32_t*)0x2000025c = 0;
+  *(uint32_t*)0x20000260 = 0;
+  *(uint32_t*)0x20000264 = 0;
+  *(uint32_t*)0x20000268 = 0;
+  *(uint32_t*)0x2000026c = 0;
+  *(uint64_t*)0x20000270 = 0;
+  __sys_io_uring_setup(0xc9f, (struct io_uring_params *) 0x20000200);
+  return 0;
+}
diff --git a/test/b5837bd5311d-test.c b/test/b5837bd5311d-test.c
new file mode 100644
index 0000000..57a2b58
--- /dev/null
+++ b/test/b5837bd5311d-test.c
@@ -0,0 +1,77 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: Check to see if wait_nr is being honored.
+ */
+#include <stdio.h>
+#include "liburing.h"
+
+int main(int argc, char *argv[])
+{
+	struct io_uring_sqe *sqe;
+	struct io_uring_cqe *cqe;
+	struct io_uring ring;
+	int ret;
+	struct __kernel_timespec ts = {
+		.tv_sec = 0,
+		.tv_nsec = 10000000
+	};
+
+	if (argc > 1)
+		return 0;
+
+	if (io_uring_queue_init(4, &ring, 0) != 0) {
+		fprintf(stderr, "ring setup failed\n");
+		return 1;
+	}
+
+	/*
+	 * First, submit the timeout sqe so we can actually finish the test
+	 * if everything is in working order.
+	 */
+	sqe = io_uring_get_sqe(&ring);
+	if (!sqe) {
+		fprintf(stderr, "get sqe failed\n");
+		return 1;
+	}
+	io_uring_prep_timeout(sqe, &ts, (unsigned)-1, 0);
+
+	ret = io_uring_submit(&ring);
+	if (ret != 1) {
+		fprintf(stderr, "Got submit %d, expected 1\n", ret);
+		return 1;
+	}
+
+	/*
+	 * Next, submit a nop and wait for two events. If everything is working
+	 * as it should, we should be waiting for more than a millisecond and we
+	 * should see two cqes. Otherwise, execution continues immediately
+	 * and we see only one cqe.
+	 */
+	sqe = io_uring_get_sqe(&ring);
+	if (!sqe) {
+		fprintf(stderr, "get sqe failed\n");
+		return 1;
+	}
+	io_uring_prep_nop(sqe);
+
+	ret = io_uring_submit_and_wait(&ring, 2);
+	if (ret != 1) {
+		fprintf(stderr, "Got submit %d, expected 1\n", ret);
+		return 1;
+	}
+
+	if (io_uring_peek_cqe(&ring, &cqe) != 0) {
+		fprintf(stderr, "Unable to peek cqe!\n");
+		return 1;
+	}
+
+	io_uring_cqe_seen(&ring, cqe);
+
+	if (io_uring_peek_cqe(&ring, &cqe) != 0) {
+		fprintf(stderr, "Unable to peek cqe!\n");
+		return 1;
+	}
+
+	io_uring_queue_exit(&ring);
+	return 0;
+}
diff --git a/test/ce593a6c480a-test.c b/test/ce593a6c480a-test.c
new file mode 100644
index 0000000..c6949f0
--- /dev/null
+++ b/test/ce593a6c480a-test.c
@@ -0,0 +1,135 @@
+/*
+ * Test 5.7 regression with task_work not being run while a task is
+ * waiting on another event in the kernel.
+ */
+#include <errno.h>
+#include <poll.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/eventfd.h>
+#include <unistd.h>
+#include <pthread.h>
+#include "liburing.h"
+#include "helpers.h"
+
+static int use_sqpoll = 0;
+
+void notify_fd(int fd)
+{
+	char buf[8] = {0, 0, 0, 0, 0, 0, 1};
+	int ret;
+
+	ret = write(fd, &buf, 8);
+	if (ret < 0)
+		perror("write");
+}
+
+void *delay_set_fd_from_thread(void *data)
+{
+	int fd = (intptr_t) data;
+
+	sleep(1);
+	notify_fd(fd);
+	return NULL;
+}
+
+int main(int argc, char *argv[])
+{
+	struct io_uring_params p = {};
+	struct io_uring ring;
+	int loop_fd, other_fd;
+	struct io_uring_sqe *sqe;
+	struct io_uring_cqe *cqe = NULL;
+	int ret, use_fd;
+	char buf[8] = {0, 0, 0, 0, 0, 0, 1};
+	pthread_t tid;
+
+	if (argc > 1)
+		return 0;
+
+	/* Create an eventfd to be registered with the loop to be
+	 * notified of events being ready
+	 */
+	loop_fd = eventfd(0, EFD_CLOEXEC);
+	if (loop_fd == -1) {
+		fprintf(stderr, "eventfd errno=%d\n", errno);
+		return 1;
+	}
+
+	/* Create an eventfd that can create events */
+	use_fd = other_fd = eventfd(0, EFD_CLOEXEC);
+	if (other_fd == -1) {
+		fprintf(stderr, "eventfd errno=%d\n", errno);
+		return 1;
+	}
+
+	if (use_sqpoll)
+		p.flags = IORING_SETUP_SQPOLL;
+
+	/* Setup the ring with a registered event fd to be notified on events */
+	ret = t_create_ring_params(8, &ring, &p);
+	if (ret == T_SETUP_SKIP)
+		return 0;
+	else if (ret < 0)
+		return ret;
+
+	ret = io_uring_register_eventfd(&ring, loop_fd);
+	if (ret < 0) {
+		fprintf(stderr, "register_eventfd=%d\n", ret);
+		return 1;
+	}
+
+	if (use_sqpoll) {
+		ret = io_uring_register_files(&ring, &other_fd, 1);
+		if (ret < 0) {
+			fprintf(stderr, "register_files=%d\n", ret);
+			return 1;
+		}
+		use_fd = 0;
+	}
+
+	/* Submit a poll operation to wait on an event in other_fd */
+	sqe = io_uring_get_sqe(&ring);
+	io_uring_prep_poll_add(sqe, use_fd, POLLIN);
+	sqe->user_data = 1;
+	if (use_sqpoll)
+		sqe->flags |= IOSQE_FIXED_FILE;
+	ret = io_uring_submit(&ring);
+	if (ret != 1) {
+		fprintf(stderr, "submit=%d\n", ret);
+		return 1;
+	}
+
+	/*
+	 * CASE 3: Hangs forever in Linux 5.7.5; Works in Linux 5.6.0 When this
+	 * code is uncommented, we don't se a notification on other_fd until
+	 * _after_ we have started the read on loop_fd. In that case, the read() on
+	 * loop_fd seems to hang forever.
+	*/
+    	pthread_create(&tid, NULL, delay_set_fd_from_thread,
+			(void*) (intptr_t) other_fd);
+
+	/* Wait on the event fd for an event to be ready */
+	ret = read(loop_fd, buf, 8);
+	if (ret < 0) {
+		perror("read");
+		return 1;
+	} else if (ret != 8) {
+		fprintf(stderr, "Odd-sized eventfd read: %d\n", ret);
+		return 1;
+	}
+
+
+	ret = io_uring_wait_cqe(&ring, &cqe);
+	if (ret) {
+		fprintf(stderr, "wait_cqe=%d\n", ret);
+		return ret;
+	}
+	if (cqe->res < 0) {
+		fprintf(stderr, "cqe->res=%d\n", cqe->res);
+		return 1;
+	}
+
+	io_uring_cqe_seen(&ring, cqe);
+	return 0;
+}
diff --git a/test/close-opath.c b/test/close-opath.c
new file mode 100644
index 0000000..f267dad
--- /dev/null
+++ b/test/close-opath.c
@@ -0,0 +1,122 @@
+// SPDX-License-Identifier: MIT
+
+#define _GNU_SOURCE 1
+#define _FILE_OFFSET_BITS 64
+
+// Test program for io_uring IORING_OP_CLOSE with O_PATH file.
+// Author: Clayton Harris <bugs@claycon.org>, 2020-06-07
+
+// linux                5.6.14-300.fc32.x86_64
+// gcc                  10.1.1-1.fc32
+// liburing.x86_64      0.5-1.fc32
+
+// gcc -O2 -Wall -Wextra -std=c11 -o close_opath close_opath.c -luring
+// ./close_opath testfilepath
+
+#include <errno.h>
+#include <fcntl.h>
+#include <liburing.h>
+#include <sys/stat.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+typedef struct
+{
+	const char *const flnames;
+	const int oflags;
+} oflgs_t;
+
+static int test_io_uring_close(struct io_uring *ring, int fd)
+{
+	struct io_uring_sqe *sqe;
+	struct io_uring_cqe *cqe;
+	int ret;
+
+	sqe = io_uring_get_sqe(ring);
+	if (!sqe) {
+		fprintf(stderr, "io_uring_get_sqe() failed\n");
+		return -ENOENT;
+	}
+
+	io_uring_prep_close(sqe, fd);
+
+	ret = io_uring_submit(ring);
+	if (ret < 0) {
+		fprintf(stderr, "io_uring_submit() failed, errno %d: %s\n",
+			-ret, strerror(-ret));
+		return ret;
+	}
+
+	ret = io_uring_wait_cqe(ring, &cqe);
+	if (ret < 0) {
+		fprintf(stderr, "io_uring_wait_cqe() failed, errno %d: %s\n",
+			-ret, strerror(-ret));
+		return ret;
+	}
+
+	ret = cqe->res;
+	io_uring_cqe_seen(ring, cqe);
+
+	if (ret < 0 && ret != -EOPNOTSUPP && ret != -EINVAL && ret != -EBADF) {
+		fprintf(stderr, "io_uring close() failed, errno %d: %s\n",
+			-ret, strerror(-ret));
+		return ret;
+	}
+
+	return 0;
+}
+
+static int open_file(const char *path, const oflgs_t *oflgs)
+{
+	int fd;
+
+	fd = openat(AT_FDCWD, path, oflgs->oflags, 0);
+	if (fd < 0) {
+		int err = errno;
+		fprintf(stderr, "openat(%s, %s) failed, errno %d: %s\n",
+			path, oflgs->flnames, err, strerror(err));
+		return -err;
+	}
+
+	return fd;
+}
+
+int main(int argc, char *argv[])
+{
+	const char *fname = ".";
+	struct io_uring ring;
+	int ret, i;
+	static const oflgs_t oflgs[] = {
+		{ "O_RDONLY", O_RDONLY },
+		{ "O_PATH", O_PATH }
+	};
+
+	ret = io_uring_queue_init(2, &ring, 0);
+	if (ret < 0) {
+		fprintf(stderr, "io_uring_queue_init() failed, errno %d: %s\n",
+			-ret, strerror(-ret));
+		return 0x02;
+	}
+
+#define OFLGS_SIZE (sizeof(oflgs) / sizeof(oflgs[0]))
+
+	ret = 0;
+	for (i = 0; i < OFLGS_SIZE; i++) {
+		int fd;
+
+		fd = open_file(fname, &oflgs[i]);
+		if (fd < 0) {
+			ret |= 0x02;
+			break;
+		}
+
+		/* Should always succeed */
+		if (test_io_uring_close(&ring, fd) < 0)
+			ret |= 0x04 << i;
+	}
+#undef OFLGS_SIZE
+
+	io_uring_queue_exit(&ring);
+	return ret;
+}
diff --git a/test/config b/test/config
new file mode 100644
index 0000000..6c0925a
--- /dev/null
+++ b/test/config
@@ -0,0 +1,10 @@
+# Copy this to config.local, uncomment and define values
+#
+# Define tests to exclude from running
+# TEST_EXCLUDE=""
+#
+# Define raw test devices (or files) for test cases, if any
+# declare -A TEST_MAP=()
+#
+# If no TEST_MAP entry exists for a test, use the ones given in TEST_FILES
+# TEST_FILES="/dev/somedevice /data/somefile"
diff --git a/test/connect.c b/test/connect.c
new file mode 100644
index 0000000..0ba3ee6
--- /dev/null
+++ b/test/connect.c
@@ -0,0 +1,395 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Check that IORING_OP_CONNECT works, with and without other side
+ * being open.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <poll.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+#include <arpa/inet.h>
+
+#include "liburing.h"
+
+static int no_connect;
+static int use_port;
+
+static int create_socket(void)
+{
+	int fd;
+
+	fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+	if (fd == -1) {
+		perror("socket()");
+		return -1;
+	}
+
+	return fd;
+}
+
+static int submit_and_wait(struct io_uring *ring, int *res)
+{
+	struct io_uring_cqe *cqe;
+	int ret;
+
+	ret = io_uring_submit_and_wait(ring, 1);
+	if (ret != 1) {
+		fprintf(stderr, "io_using_submit: got %d\n", ret);
+		return 1;
+	}
+
+	ret = io_uring_peek_cqe(ring, &cqe);
+	if (ret) {
+		fprintf(stderr, "io_uring_peek_cqe(): no cqe returned");
+		return 1;
+	}
+
+	*res = cqe->res;
+	io_uring_cqe_seen(ring, cqe);
+	return 0;
+}
+
+static int wait_for(struct io_uring *ring, int fd, int mask)
+{
+	struct io_uring_sqe *sqe;
+	int ret, res;
+
+	sqe = io_uring_get_sqe(ring);
+	if (!sqe) {
+		fprintf(stderr, "unable to get sqe\n");
+		return -1;
+	}
+
+	io_uring_prep_poll_add(sqe, fd, mask);
+	sqe->user_data = 2;
+
+	ret = submit_and_wait(ring, &res);
+	if (ret)
+		return -1;
+
+	if (res < 0) {
+		fprintf(stderr, "poll(): failed with %d\n", res);
+		return -1;
+	}
+
+	return res;
+}
+
+static int listen_on_socket(int fd)
+{
+	struct sockaddr_in addr;
+	int ret;
+
+	memset(&addr, 0, sizeof(addr));
+	addr.sin_family = AF_INET;
+	addr.sin_port = use_port;
+	addr.sin_addr.s_addr = 0x0100007fU;
+
+	ret = bind(fd, (struct sockaddr*)&addr, sizeof(addr));
+	if (ret == -1) {
+		perror("bind()");
+		return -1;
+	}
+
+	ret = listen(fd, 128);
+	if (ret == -1) {
+		perror("listen()");
+		return -1;
+	}
+
+	return 0;
+}
+
+static int configure_connect(int fd, struct sockaddr_in* addr)
+{
+	int ret, val = 1;
+
+	ret = setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &val, sizeof(val));
+	if (ret == -1) {
+		perror("setsockopt()");
+		return -1;
+	}
+
+	ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
+	if (ret == -1) {
+		perror("setsockopt()");
+		return -1;
+	}
+
+	memset(addr, 0, sizeof(*addr));
+	addr->sin_family = AF_INET;
+	addr->sin_port = use_port;
+	ret = inet_aton("127.0.0.1", &addr->sin_addr);
+	return ret;
+}
+
+static int connect_socket(struct io_uring *ring, int fd, int *code)
+{
+	struct sockaddr_in addr;
+	int ret, res;
+	socklen_t code_len = sizeof(*code);
+	struct io_uring_sqe *sqe;
+
+	if (configure_connect(fd, &addr) == -1)
+		return -1;
+
+	sqe = io_uring_get_sqe(ring);
+	if (!sqe) {
+		fprintf(stderr, "unable to get sqe\n");
+		return -1;
+	}
+
+	io_uring_prep_connect(sqe, fd, (struct sockaddr*)&addr, sizeof(addr));
+	sqe->user_data = 1;
+
+	ret = submit_and_wait(ring, &res);
+	if (ret)
+		return -1;
+
+	if (res == -EINPROGRESS) {
+		ret = wait_for(ring, fd, POLLOUT | POLLHUP | POLLERR);
+		if (ret == -1)
+			return -1;
+
+		int ev = (ret & POLLOUT) || (ret & POLLHUP) || (ret & POLLERR);
+		if (!ev) {
+			fprintf(stderr, "poll(): returned invalid value %#x\n", ret);
+			return -1;
+		}
+
+		ret = getsockopt(fd, SOL_SOCKET, SO_ERROR, code, &code_len);
+		if (ret == -1) {
+			perror("getsockopt()");
+			return -1;
+		}
+	} else
+		*code = res;
+	return 0;
+}
+
+static int test_connect_with_no_peer(struct io_uring *ring)
+{
+	int connect_fd;
+	int ret, code;
+
+	connect_fd = create_socket();
+	if (connect_fd == -1)
+		return -1;
+
+	ret = connect_socket(ring, connect_fd, &code);
+	if (ret == -1)
+		goto err;
+
+	if (code != -ECONNREFUSED) {
+		if (code == -EINVAL || code == -EBADF || code == -EOPNOTSUPP) {
+			fprintf(stdout, "No connect support, skipping\n");
+			no_connect = 1;
+			goto out;
+		}
+		fprintf(stderr, "connect failed with %d\n", code);
+		goto err;
+	}
+
+out:
+	close(connect_fd);
+	return 0;
+
+err:
+	close(connect_fd);
+	return -1;
+}
+
+static int test_connect(struct io_uring *ring)
+{
+	int accept_fd;
+	int connect_fd;
+	int ret, code;
+
+	accept_fd = create_socket();
+	if (accept_fd == -1)
+		return -1;
+
+	ret = listen_on_socket(accept_fd);
+	if (ret == -1)
+		goto err1;
+
+	connect_fd = create_socket();
+	if (connect_fd == -1)
+		goto err1;
+
+	ret = connect_socket(ring, connect_fd, &code);
+	if (ret == -1)
+		goto err2;
+
+	if (code != 0) {
+		fprintf(stderr, "connect failed with %d\n", code);
+		goto err2;
+	}
+
+	close(connect_fd);
+	close(accept_fd);
+
+	return 0;
+
+err2:
+	close(connect_fd);
+
+err1:
+	close(accept_fd);
+	return -1;
+}
+
+static int test_connect_timeout(struct io_uring *ring)
+{
+	int connect_fd[2] = {-1, -1};
+	int accept_fd = -1;
+	int ret, code;
+	struct sockaddr_in addr;
+	struct io_uring_sqe *sqe;
+	struct __kernel_timespec ts = {.tv_sec = 0, .tv_nsec = 100000};
+
+	connect_fd[0] = create_socket();
+	if (connect_fd[0] == -1)
+		return -1;
+
+	connect_fd[1] = create_socket();
+	if (connect_fd[1] == -1)
+		goto err;
+
+	accept_fd = create_socket();
+	if (accept_fd == -1)
+		goto err;
+
+	if (configure_connect(connect_fd[0], &addr) == -1)
+		goto err;
+
+	if (configure_connect(connect_fd[1], &addr) == -1)
+		goto err;
+
+	ret = bind(accept_fd, (struct sockaddr*)&addr, sizeof(addr));
+	if (ret == -1) {
+		perror("bind()");
+		goto err;
+	}
+
+	ret = listen(accept_fd, 0);  // no backlog in order to block connect_fd[1]
+	if (ret == -1) {
+		perror("listen()");
+		goto err;
+	}
+
+	// We first connect with one client socket in order to fill the accept queue.
+	ret = connect_socket(ring, connect_fd[0], &code);
+	if (ret == -1 || code != 0) {
+		fprintf(stderr, "unable to connect\n");
+		goto err;
+	}
+
+	// We do not offload completion events from listening socket on purpose. 
+	// This way we create a state where the second connect request being stalled by OS.  
+	sqe = io_uring_get_sqe(ring);
+	if (!sqe) {
+		fprintf(stderr, "unable to get sqe\n");
+		goto err;
+	}
+
+	io_uring_prep_connect(sqe, connect_fd[1], (struct sockaddr*)&addr, sizeof(addr));
+	sqe->user_data = 1;
+	sqe->flags |= IOSQE_IO_LINK;
+
+	sqe = io_uring_get_sqe(ring);
+	if (!sqe) {
+		fprintf(stderr, "unable to get sqe\n");
+		goto err;
+	}
+	io_uring_prep_link_timeout(sqe, &ts, 0);
+	sqe->user_data = 2;
+
+	ret = io_uring_submit(ring);
+	if (ret != 2) {
+		fprintf(stderr, "submitted %d\n", ret);
+		return -1;
+	}
+
+	for (int i = 0; i < 2; i++) {
+		int expected;
+		struct io_uring_cqe *cqe;
+
+		ret = io_uring_wait_cqe(ring, &cqe);
+		if (ret) {
+			fprintf(stderr, "wait_cqe=%d\n", ret);
+			return -1;
+		}
+
+		expected = (cqe->user_data == 1) ? -ECANCELED : -ETIME;
+		if (expected != cqe->res) {
+			fprintf(stderr, "cqe %d, res %d, wanted %d\n", 
+					(int)cqe->user_data, cqe->res, expected);
+			goto err;
+		}
+		io_uring_cqe_seen(ring, cqe);
+	}
+
+	close(connect_fd[0]);
+	close(connect_fd[1]);
+	close(accept_fd);
+	return 0;
+
+err:
+	if (connect_fd[0] != -1)
+		close(connect_fd[0]);
+	if (connect_fd[1] != -1)
+		close(connect_fd[1]);
+		
+	if (accept_fd != -1)
+		close(accept_fd);
+	return -1;
+}
+
+int main(int argc, char *argv[])
+{
+	struct io_uring ring;
+	int ret;
+
+	if (argc > 1)
+		return 0;
+
+	ret = io_uring_queue_init(8, &ring, 0);
+	if (ret) {
+		fprintf(stderr, "io_uring_queue_setup() = %d\n", ret);
+		return 1;
+	}
+
+	srand(getpid());
+	use_port = (rand() % 61440) + 4096;
+
+	ret = test_connect_with_no_peer(&ring);
+	if (ret == -1) {
+		fprintf(stderr, "test_connect_with_no_peer(): failed\n");
+		return 1;
+	}
+	if (no_connect)
+		return 0;
+
+	ret = test_connect(&ring);
+	if (ret == -1) {
+		fprintf(stderr, "test_connect(): failed\n");
+		return 1;
+	}
+
+	ret = test_connect_timeout(&ring);
+	if (ret == -1) {
+		fprintf(stderr, "test_connect_timeout(): failed\n");
+		return 1;
+	}
+
+	io_uring_queue_exit(&ring);
+	return 0;
+}
diff --git a/test/cq-full.c b/test/cq-full.c
new file mode 100644
index 0000000..5c4041b
--- /dev/null
+++ b/test/cq-full.c
@@ -0,0 +1,96 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: test CQ ring overflow
+ *
+ */
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+
+#include "liburing.h"
+
+static int queue_n_nops(struct io_uring *ring, int n)
+{
+	struct io_uring_sqe *sqe;
+	int i, ret;
+
+	for (i = 0; i < n; i++) {
+		sqe = io_uring_get_sqe(ring);
+		if (!sqe) {
+			printf("get sqe failed\n");
+			goto err;
+		}
+
+		io_uring_prep_nop(sqe);
+	}
+
+	ret = io_uring_submit(ring);
+	if (ret < n) {
+		printf("Submitted only %d\n", ret);
+		goto err;
+	} else if (ret < 0) {
+		printf("sqe submit failed: %d\n", ret);
+		goto err;
+	}
+
+	return 0;
+err:
+	return 1;
+}
+
+int main(int argc, char *argv[])
+{
+	struct io_uring_cqe *cqe;
+	struct io_uring_params p;
+	struct io_uring ring;
+	int i, ret;
+
+	if (argc > 1)
+		return 0;
+
+	memset(&p, 0, sizeof(p));
+	ret = io_uring_queue_init_params(4, &ring, &p);
+	if (ret) {
+		printf("ring setup failed\n");
+		return 1;
+
+	}
+
+	if (queue_n_nops(&ring, 4))
+		goto err;
+	if (queue_n_nops(&ring, 4))
+		goto err;
+	if (queue_n_nops(&ring, 4))
+		goto err;
+
+	i = 0;
+	do {
+		ret = io_uring_peek_cqe(&ring, &cqe);
+		if (ret < 0) {
+			if (ret == -EAGAIN)
+				break;
+			printf("wait completion %d\n", ret);
+			goto err;
+		}
+		io_uring_cqe_seen(&ring, cqe);
+		if (!cqe)
+			break;
+		i++;
+	} while (1);
+
+	if (i < 8 ||
+	    ((*ring.cq.koverflow != 4) && !(p.features & IORING_FEAT_NODROP))) {
+		printf("CQ overflow fail: %d completions, %u overflow\n", i,
+				*ring.cq.koverflow);
+		goto err;
+	}
+
+	io_uring_queue_exit(&ring);
+	return 0;
+err:
+	io_uring_queue_exit(&ring);
+	return 1;
+}
diff --git a/test/cq-overflow.c b/test/cq-overflow.c
new file mode 100644
index 0000000..945dc93
--- /dev/null
+++ b/test/cq-overflow.c
@@ -0,0 +1,293 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: run various CQ ring overflow tests
+ *
+ */
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+
+#include "helpers.h"
+#include "liburing.h"
+
+#define FILE_SIZE	(256 * 1024)
+#define BS		4096
+#define BUFFERS		(FILE_SIZE / BS)
+
+static struct iovec *vecs;
+
+#define ENTRIES	8
+
+static int test_io(const char *file, unsigned long usecs, unsigned *drops, int fault)
+{
+	struct io_uring_sqe *sqe;
+	struct io_uring_cqe *cqe;
+	struct io_uring_params p;
+	unsigned reaped, total;
+	struct io_uring ring;
+	int nodrop, i, fd, ret;
+
+	fd = open(file, O_RDONLY | O_DIRECT);
+	if (fd < 0) {
+		perror("file open");
+		goto err;
+	}
+
+	memset(&p, 0, sizeof(p));
+	ret = io_uring_queue_init_params(ENTRIES, &ring, &p);
+	if (ret) {
+		fprintf(stderr, "ring create failed: %d\n", ret);
+		goto err;
+	}
+	nodrop = 0;
+	if (p.features & IORING_FEAT_NODROP)
+		nodrop = 1;
+
+	total = 0;
+	for (i = 0; i < BUFFERS / 2; i++) {
+		off_t offset;
+
+		sqe = io_uring_get_sqe(&ring);
+		if (!sqe) {
+			fprintf(stderr, "sqe get failed\n");
+			goto err;
+		}
+		offset = BS * (rand() % BUFFERS);
+		if (fault && i == ENTRIES + 4)
+			vecs[i].iov_base = NULL;
+		io_uring_prep_readv(sqe, fd, &vecs[i], 1, offset);
+
+		ret = io_uring_submit(&ring);
+		if (nodrop && ret == -EBUSY) {
+			*drops = 1;
+			total = i;
+			break;
+		} else if (ret != 1) {
+			fprintf(stderr, "submit got %d, wanted %d\n", ret, 1);
+			total = i;
+			break;
+		}
+		total++;
+	}
+
+	if (*drops)
+		goto reap_it;
+
+	usleep(usecs);
+
+	for (i = total; i < BUFFERS; i++) {
+		off_t offset;
+
+		sqe = io_uring_get_sqe(&ring);
+		if (!sqe) {
+			fprintf(stderr, "sqe get failed\n");
+			goto err;
+		}
+		offset = BS * (rand() % BUFFERS);
+		io_uring_prep_readv(sqe, fd, &vecs[i], 1, offset);
+
+		ret = io_uring_submit(&ring);
+		if (nodrop && ret == -EBUSY) {
+			*drops = 1;
+			break;
+		} else if (ret != 1) {
+			fprintf(stderr, "submit got %d, wanted %d\n", ret, 1);
+			break;
+		}
+		total++;
+	}
+
+reap_it:
+	reaped = 0;
+	do {
+		if (nodrop) {
+			/* nodrop should never lose events */
+			if (reaped == total)
+				break;
+		} else {
+			if (reaped + *ring.cq.koverflow == total)
+				break;
+		}
+		ret = io_uring_wait_cqe(&ring, &cqe);
+		if (ret) {
+			fprintf(stderr, "wait_cqe=%d\n", ret);
+			goto err;
+		}
+		if (cqe->res != BS) {
+			if (!(fault && cqe->res == -EFAULT)) {
+				fprintf(stderr, "cqe res %d, wanted %d\n",
+						cqe->res, BS);
+				goto err;
+			}
+		}
+		io_uring_cqe_seen(&ring, cqe);
+		reaped++;
+	} while (1);
+
+	if (!io_uring_peek_cqe(&ring, &cqe)) {
+		fprintf(stderr, "found unexpected completion\n");
+		goto err;
+	}
+
+	if (!nodrop) {
+		*drops = *ring.cq.koverflow;
+	} else if (*ring.cq.koverflow) {
+		fprintf(stderr, "Found %u overflows\n", *ring.cq.koverflow);
+		goto err;
+	}
+
+	io_uring_queue_exit(&ring);
+	close(fd);
+	return 0;
+err:
+	if (fd != -1)
+		close(fd);
+	io_uring_queue_exit(&ring);
+	return 1;
+}
+
+static int reap_events(struct io_uring *ring, unsigned nr_events, int do_wait)
+{
+	struct io_uring_cqe *cqe;
+	int i, ret = 0, seq = 0;
+
+	for (i = 0; i < nr_events; i++) {
+		if (do_wait)
+			ret = io_uring_wait_cqe(ring, &cqe);
+		else
+			ret = io_uring_peek_cqe(ring, &cqe);
+		if (ret) {
+			if (ret != -EAGAIN)
+				fprintf(stderr, "cqe peek failed: %d\n", ret);
+			break;
+		}
+		if (cqe->user_data != seq) {
+			fprintf(stderr, "cqe sequence out-of-order\n");
+			fprintf(stderr, "got %d, wanted %d\n", (int) cqe->user_data,
+					seq);
+			return -EINVAL;
+		}
+		seq++;
+		io_uring_cqe_seen(ring, cqe);
+	}
+
+	return i ? i : ret;
+}
+
+/*
+ * Submit some NOPs and watch if the overflow is correct
+ */
+static int test_overflow(void)
+{
+	struct io_uring ring;
+	struct io_uring_params p;
+	struct io_uring_sqe *sqe;
+	unsigned pending;
+	int ret, i, j;
+
+	memset(&p, 0, sizeof(p));
+	ret = io_uring_queue_init_params(4, &ring, &p);
+	if (ret) {
+		fprintf(stderr, "io_uring_queue_init failed %d\n", ret);
+		return 1;
+	}
+
+	/* submit 4x4 SQEs, should overflow the ring by 8 */
+	pending = 0;
+	for (i = 0; i < 4; i++) {
+		for (j = 0; j < 4; j++) {
+			sqe = io_uring_get_sqe(&ring);
+			if (!sqe) {
+				fprintf(stderr, "get sqe failed\n");
+				goto err;
+			}
+
+			io_uring_prep_nop(sqe);
+			sqe->user_data = (i * 4) + j;
+		}
+
+		ret = io_uring_submit(&ring);
+		if (ret == 4) {
+			pending += 4;
+			continue;
+		}
+		if (p.features & IORING_FEAT_NODROP) {
+			if (ret == -EBUSY)
+				break;
+		}
+		fprintf(stderr, "sqe submit failed: %d\n", ret);
+		goto err;
+	}
+
+	/* we should now have 8 completions ready */
+	ret = reap_events(&ring, pending, 0);
+	if (ret < 0)
+		goto err;
+
+	if (!(p.features & IORING_FEAT_NODROP)) {
+		if (*ring.cq.koverflow != 8) {
+			fprintf(stderr, "cq ring overflow %d, expected 8\n",
+					*ring.cq.koverflow);
+			goto err;
+		}
+	}
+	io_uring_queue_exit(&ring);
+	return 0;
+err:
+	io_uring_queue_exit(&ring);
+	return 1;
+}
+
+int main(int argc, char *argv[])
+{
+	unsigned iters, drops;
+	unsigned long usecs;
+	int ret;
+
+	if (argc > 1)
+		return 0;
+
+	ret = test_overflow();
+	if (ret) {
+		printf("test_overflow failed\n");
+		return ret;
+	}
+
+	t_create_file(".basic-rw", FILE_SIZE);
+
+	vecs = t_create_buffers(BUFFERS, BS);
+
+	iters = 0;
+	usecs = 1000;
+	do {
+		drops = 0;
+
+		if (test_io(".basic-rw", usecs, &drops, 0)) {
+			fprintf(stderr, "test_io nofault failed\n");
+			goto err;
+		}
+		if (drops)
+			break;
+		usecs = (usecs * 12) / 10;
+		iters++;
+	} while (iters < 40);
+
+	if (test_io(".basic-rw", usecs, &drops, 0)) {
+		fprintf(stderr, "test_io nofault failed\n");
+		goto err;
+	}
+
+	if (test_io(".basic-rw", usecs, &drops, 1)) {
+		fprintf(stderr, "test_io fault failed\n");
+		goto err;
+	}
+
+	unlink(".basic-rw");
+	return 0;
+err:
+	unlink(".basic-rw");
+	return 1;
+}
diff --git a/test/cq-peek-batch.c b/test/cq-peek-batch.c
new file mode 100644
index 0000000..6c47bec
--- /dev/null
+++ b/test/cq-peek-batch.c
@@ -0,0 +1,102 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: test CQ peek-batch
+ *
+ */
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+
+#include "liburing.h"
+
+static int queue_n_nops(struct io_uring *ring, int n, int offset)
+{
+	struct io_uring_sqe *sqe;
+	int i, ret;
+
+	for (i = 0; i < n; i++) {
+		sqe = io_uring_get_sqe(ring);
+		if (!sqe) {
+			printf("get sqe failed\n");
+			goto err;
+		}
+
+		io_uring_prep_nop(sqe);
+		sqe->user_data = i + offset;
+	}
+
+	ret = io_uring_submit(ring);
+	if (ret < n) {
+		printf("Submitted only %d\n", ret);
+		goto err;
+	} else if (ret < 0) {
+		printf("sqe submit failed: %d\n", ret);
+		goto err;
+	}
+
+	return 0;
+err:
+	return 1;
+}
+
+#define CHECK_BATCH(ring, got, cqes, count, expected) do {\
+	got = io_uring_peek_batch_cqe((ring), cqes, count);\
+	if (got != expected) {\
+		printf("Got %d CQs, expected %d\n", got, expected);\
+		goto err;\
+	}\
+} while(0)
+
+int main(int argc, char *argv[])
+{
+	struct io_uring_cqe *cqes[8];
+	struct io_uring ring;
+	int ret, i;
+	unsigned got;
+
+	if (argc > 1)
+		return 0;
+
+	ret = io_uring_queue_init(4, &ring, 0);
+	if (ret) {
+		printf("ring setup failed\n");
+		return 1;
+
+	}
+
+	CHECK_BATCH(&ring, got, cqes, 4, 0);
+	if (queue_n_nops(&ring, 4, 0))
+		goto err;
+
+	CHECK_BATCH(&ring, got, cqes, 4, 4);
+	for (i=0;i<4;i++) {
+		if (i != cqes[i]->user_data) {
+			printf("Got user_data %" PRIu64 ", expected %d\n",
+				(uint64_t) cqes[i]->user_data, i);
+			goto err;
+		}
+	}
+
+	if (queue_n_nops(&ring, 4, 4))
+		goto err;
+
+	io_uring_cq_advance(&ring, 4);
+	CHECK_BATCH(&ring, got, cqes, 4, 4);
+	for (i=0;i<4;i++) {
+		if (i + 4 != cqes[i]->user_data) {
+			printf("Got user_data %" PRIu64 ", expected %d\n",
+				(uint64_t) cqes[i]->user_data, i + 4);
+			goto err;
+		}
+	}
+
+	io_uring_cq_advance(&ring, 8);
+	io_uring_queue_exit(&ring);
+	return 0;
+err:
+	io_uring_queue_exit(&ring);
+	return 1;
+}
diff --git a/test/cq-ready.c b/test/cq-ready.c
new file mode 100644
index 0000000..7af7e54
--- /dev/null
+++ b/test/cq-ready.c
@@ -0,0 +1,94 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: test CQ ready
+ *
+ */
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+
+#include "liburing.h"
+
+static int queue_n_nops(struct io_uring *ring, int n)
+{
+	struct io_uring_sqe *sqe;
+	int i, ret;
+
+	for (i = 0; i < n; i++) {
+		sqe = io_uring_get_sqe(ring);
+		if (!sqe) {
+			printf("get sqe failed\n");
+			goto err;
+		}
+
+		io_uring_prep_nop(sqe);
+	}
+
+	ret = io_uring_submit(ring);
+	if (ret < n) {
+		printf("Submitted only %d\n", ret);
+		goto err;
+	} else if (ret < 0) {
+		printf("sqe submit failed: %d\n", ret);
+		goto err;
+	}
+
+	return 0;
+err:
+	return 1;
+}
+
+#define CHECK_READY(ring, expected) do {\
+	ready = io_uring_cq_ready((ring));\
+	if (ready != expected) {\
+		printf("Got %d CQs ready, expected %d\n", ready, expected);\
+		goto err;\
+	}\
+} while(0)
+
+int main(int argc, char *argv[])
+{
+	struct io_uring ring;
+	int ret;
+	unsigned ready;
+
+	if (argc > 1)
+		return 0;
+
+	ret = io_uring_queue_init(4, &ring, 0);
+	if (ret) {
+		printf("ring setup failed\n");
+		return 1;
+
+	}
+
+	CHECK_READY(&ring, 0);
+	if (queue_n_nops(&ring, 4))
+		goto err;
+
+	CHECK_READY(&ring, 4);
+	io_uring_cq_advance(&ring, 4);
+	CHECK_READY(&ring, 0);
+	if (queue_n_nops(&ring, 4))
+		goto err;
+
+	CHECK_READY(&ring, 4);
+
+	io_uring_cq_advance(&ring, 1);
+	CHECK_READY(&ring, 3);
+
+	io_uring_cq_advance(&ring, 2);
+	CHECK_READY(&ring, 1);
+
+	io_uring_cq_advance(&ring, 1);
+	CHECK_READY(&ring, 0);
+
+	io_uring_queue_exit(&ring);
+	return 0;
+err:
+	io_uring_queue_exit(&ring);
+	return 1;
+}
diff --git a/test/cq-size.c b/test/cq-size.c
new file mode 100644
index 0000000..b7dd5b4
--- /dev/null
+++ b/test/cq-size.c
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: test CQ ring sizing
+ */
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+
+#include "liburing.h"
+
+int main(int argc, char *argv[])
+{
+	struct io_uring_params p;
+	struct io_uring ring;
+	int ret;
+
+	if (argc > 1)
+		return 0;
+
+	memset(&p, 0, sizeof(p));
+	p.flags = IORING_SETUP_CQSIZE;
+	p.cq_entries = 64;
+
+	ret = io_uring_queue_init_params(4, &ring, &p);
+	if (ret) {
+		if (ret == -EINVAL) {
+			printf("Skipped, not supported on this kernel\n");
+			goto done;
+		}
+		printf("ring setup failed\n");
+		return 1;
+	}
+
+	if (p.cq_entries < 64) {
+		printf("cq entries invalid (%d)\n", p.cq_entries);
+		goto err;
+	}
+	io_uring_queue_exit(&ring);
+
+	memset(&p, 0, sizeof(p));
+	p.flags = IORING_SETUP_CQSIZE;
+	p.cq_entries = 0;
+
+	ret = io_uring_queue_init_params(4, &ring, &p);
+	if (ret >= 0 || errno != EINVAL) {
+		printf("zero sized cq ring succeeded\n");
+		goto err;
+	}
+
+done:
+	return 0;
+err:
+	io_uring_queue_exit(&ring);
+	return 1;
+}
diff --git a/test/d4ae271dfaae-test.c b/test/d4ae271dfaae-test.c
new file mode 100644
index 0000000..80d3f71
--- /dev/null
+++ b/test/d4ae271dfaae-test.c
@@ -0,0 +1,101 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Test case for SQPOLL missing a 'ret' clear in case of busy.
+ *
+ * Heavily based on a test case from
+ * Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+
+#include "helpers.h"
+#include "liburing.h"
+
+#define FILE_SIZE	(128 * 1024)
+
+int main(int argc, char *argv[])
+{
+	struct io_uring ring;
+	int i, fd, ret;
+	struct io_uring_sqe *sqe;
+	struct io_uring_cqe *cqe;
+	struct iovec *iovecs;
+	struct io_uring_params p;
+	char *fname;
+	void *buf;
+
+	if (geteuid()) {
+		fprintf(stdout, "Test requires root, skipping\n");
+		return 0;
+	}
+
+	memset(&p, 0, sizeof(p));
+	p.flags = IORING_SETUP_SQPOLL;
+	ret = t_create_ring_params(4, &ring, &p);
+	if (ret == T_SETUP_SKIP)
+		return 0;
+	else if (ret < 0)
+		return 1;
+
+	if (argc > 1) {
+		fname = argv[1];
+	} else {
+		fname = ".sqpoll.tmp";
+		t_create_file(fname, FILE_SIZE);
+	}
+
+	fd = open(fname, O_RDONLY | O_DIRECT);
+	if (fd < 0) {
+		perror("open");
+		goto out;
+	}
+
+	iovecs = t_calloc(10, sizeof(struct iovec));
+	for (i = 0; i < 10; i++) {
+		t_posix_memalign(&buf, 4096, 4096);
+		iovecs[i].iov_base = buf;
+		iovecs[i].iov_len = 4096;
+	}
+
+	ret = io_uring_register_files(&ring, &fd, 1);
+	if (ret < 0) {
+		fprintf(stderr, "register files %d\n", ret);
+		goto out;
+	}
+
+	for (i = 0; i < 10; i++) {
+		sqe = io_uring_get_sqe(&ring);
+		if (!sqe)
+			break;
+
+		io_uring_prep_readv(sqe, 0, &iovecs[i], 1, 0);
+		sqe->flags |= IOSQE_FIXED_FILE;
+
+		ret = io_uring_submit(&ring);
+		usleep(1000);
+	}
+
+	for (i = 0; i < 10; i++) {
+		ret = io_uring_wait_cqe(&ring, &cqe);
+		if (ret) {
+			fprintf(stderr, "wait_cqe=%d\n", ret);
+			break;
+		}
+		if (cqe->res != 4096) {
+			fprintf(stderr, "ret=%d, wanted 4096\n", cqe->res);
+			ret = 1;
+			break;
+		}
+		io_uring_cqe_seen(&ring, cqe);
+	}
+
+	close(fd);
+out:
+	if (fname != argv[1])
+		unlink(fname);
+	io_uring_queue_exit(&ring);
+	return ret;
+}
diff --git a/test/d77a67ed5f27-test.c b/test/d77a67ed5f27-test.c
new file mode 100644
index 0000000..e56fdcd
--- /dev/null
+++ b/test/d77a67ed5f27-test.c
@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: MIT */
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <signal.h>
+#include <stdlib.h>
+#include "liburing.h"
+#include "helpers.h"
+
+static void sig_alrm(int sig)
+{
+	fprintf(stderr, "Timed out!\n");
+	exit(1);
+}
+
+int main(int argc, char *argv[])
+{
+	struct io_uring_sqe *sqe;
+	struct io_uring_cqe *cqe;
+	struct io_uring_params p;
+	struct io_uring ring;
+	int ret, data;
+
+	if (argc > 1)
+		return 0;
+
+	signal(SIGALRM, sig_alrm);
+
+	memset(&p, 0, sizeof(p));
+	p.sq_thread_idle = 100;
+	p.flags = IORING_SETUP_SQPOLL;
+	ret = t_create_ring_params(4, &ring, &p);
+	if (ret == T_SETUP_SKIP)
+		return 0;
+	else if (ret < 0)
+		return 1;
+
+	/* make sure sq thread is sleeping at this point */
+	usleep(150000);
+	alarm(1);
+
+	sqe = io_uring_get_sqe(&ring);
+	if (!sqe) {
+		fprintf(stderr, "sqe get failed\n");
+		return 1;
+	}
+
+	io_uring_prep_nop(sqe);
+	io_uring_sqe_set_data(sqe, (void *) (unsigned long) 42);
+	io_uring_submit_and_wait(&ring, 1);
+
+	ret = io_uring_peek_cqe(&ring, &cqe);
+	if (ret) {
+		fprintf(stderr, "cqe get failed\n");
+		return 1;
+	}
+
+	data = (unsigned long) io_uring_cqe_get_data(cqe);
+	if (data != 42) {
+		fprintf(stderr, "invalid data: %d\n", data);
+		return 1;
+	}
+
+	return 0;
+}
diff --git a/test/defer.c b/test/defer.c
new file mode 100644
index 0000000..885cf5c
--- /dev/null
+++ b/test/defer.c
@@ -0,0 +1,308 @@
+/* SPDX-License-Identifier: MIT */
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <sys/uio.h>
+#include <stdbool.h>
+
+#include "helpers.h"
+#include "liburing.h"
+
+struct test_context {
+	struct io_uring *ring;
+	struct io_uring_sqe **sqes;
+	struct io_uring_cqe *cqes;
+	int nr;
+};
+
+static void free_context(struct test_context *ctx)
+{
+	free(ctx->sqes);
+	free(ctx->cqes);
+	memset(ctx, 0, sizeof(*ctx));
+}
+
+static int init_context(struct test_context *ctx, struct io_uring *ring, int nr)
+{
+	struct io_uring_sqe *sqe;
+	int i;
+
+	memset(ctx, 0, sizeof(*ctx));
+	ctx->nr = nr;
+	ctx->ring = ring;
+	ctx->sqes = t_malloc(nr * sizeof(*ctx->sqes));
+	ctx->cqes = t_malloc(nr * sizeof(*ctx->cqes));
+
+	if (!ctx->sqes || !ctx->cqes)
+		goto err;
+
+	for (i = 0; i < nr; i++) {
+		sqe = io_uring_get_sqe(ring);
+		if (!sqe)
+			goto err;
+		io_uring_prep_nop(sqe);
+		sqe->user_data = i;
+		ctx->sqes[i] = sqe;
+	}
+
+	return 0;
+err:
+	free_context(ctx);
+	printf("init context failed\n");
+	return 1;
+}
+
+static int wait_cqes(struct test_context *ctx)
+{
+	int ret, i;
+	struct io_uring_cqe *cqe;
+
+	for (i = 0; i < ctx->nr; i++) {
+		ret = io_uring_wait_cqe(ctx->ring, &cqe);
+
+		if (ret < 0) {
+			printf("wait_cqes: wait completion %d\n", ret);
+			return 1;
+		}
+		memcpy(&ctx->cqes[i], cqe, sizeof(*cqe));
+		io_uring_cqe_seen(ctx->ring, cqe);
+	}
+
+	return 0;
+}
+
+static int test_cancelled_userdata(struct io_uring *ring)
+{
+	struct test_context ctx;
+	int ret, i, nr = 100;
+
+	if (init_context(&ctx, ring, nr))
+		return 1;
+
+	for (i = 0; i < nr; i++)
+		ctx.sqes[i]->flags |= IOSQE_IO_LINK;
+
+	ret = io_uring_submit(ring);
+	if (ret <= 0) {
+		printf("sqe submit failed: %d\n", ret);
+		goto err;
+	}
+
+	if (wait_cqes(&ctx))
+		goto err;
+
+	for (i = 0; i < nr; i++) {
+		if (i != ctx.cqes[i].user_data) {
+			printf("invalid user data\n");
+			goto err;
+		}
+	}
+
+	free_context(&ctx);
+	return 0;
+err:
+	free_context(&ctx);
+	return 1;
+}
+
+static int test_thread_link_cancel(struct io_uring *ring)
+{
+	struct test_context ctx;
+	int ret, i, nr = 100;
+
+	if (init_context(&ctx, ring, nr))
+		return 1;
+
+	for (i = 0; i < nr; i++)
+		ctx.sqes[i]->flags |= IOSQE_IO_LINK;
+
+	ret = io_uring_submit(ring);
+	if (ret <= 0) {
+		printf("sqe submit failed: %d\n", ret);
+		goto err;
+	}
+
+	if (wait_cqes(&ctx))
+		goto err;
+
+	for (i = 0; i < nr; i++) {
+		bool fail = false;
+
+		if (i == 0)
+			fail = (ctx.cqes[i].res != -EINVAL);
+		else
+			fail = (ctx.cqes[i].res != -ECANCELED);
+
+		if (fail) {
+			printf("invalid status\n");
+			goto err;
+		}
+	}
+
+	free_context(&ctx);
+	return 0;
+err:
+	free_context(&ctx);
+	return 1;
+}
+
+static int test_drain_with_linked_timeout(struct io_uring *ring)
+{
+	const int nr = 3;
+	struct __kernel_timespec ts = { .tv_sec = 1, .tv_nsec = 0, };
+	struct test_context ctx;
+	int ret, i;
+
+	if (init_context(&ctx, ring, nr * 2))
+		return 1;
+
+	for (i = 0; i < nr; i++) {
+		io_uring_prep_timeout(ctx.sqes[2 * i], &ts, 0, 0);
+		ctx.sqes[2 * i]->flags |= IOSQE_IO_LINK | IOSQE_IO_DRAIN;
+		io_uring_prep_link_timeout(ctx.sqes[2 * i + 1], &ts, 0);
+	}
+
+	ret = io_uring_submit(ring);
+	if (ret <= 0) {
+		printf("sqe submit failed: %d\n", ret);
+		goto err;
+	}
+
+	if (wait_cqes(&ctx))
+		goto err;
+
+	free_context(&ctx);
+	return 0;
+err:
+	free_context(&ctx);
+	return 1;
+}
+
+static int run_drained(struct io_uring *ring, int nr)
+{
+	struct test_context ctx;
+	int ret, i;
+
+	if (init_context(&ctx, ring, nr))
+		return 1;
+
+	for (i = 0; i < nr; i++)
+		ctx.sqes[i]->flags |= IOSQE_IO_DRAIN;
+
+	ret = io_uring_submit(ring);
+	if (ret <= 0) {
+		printf("sqe submit failed: %d\n", ret);
+		goto err;
+	}
+
+	if (wait_cqes(&ctx))
+		goto err;
+
+	free_context(&ctx);
+	return 0;
+err:
+	free_context(&ctx);
+	return 1;
+}
+
+static int test_overflow_hung(struct io_uring *ring)
+{
+	struct io_uring_sqe *sqe;
+	int ret, nr = 10;
+
+	while (*ring->cq.koverflow != 1000) {
+		sqe = io_uring_get_sqe(ring);
+		if (!sqe) {
+			printf("get sqe failed\n");
+			return 1;
+		}
+
+		io_uring_prep_nop(sqe);
+		ret = io_uring_submit(ring);
+		if (ret <= 0) {
+			printf("sqe submit failed: %d\n", ret);
+			return 1;
+		}
+	}
+
+	return run_drained(ring, nr);
+}
+
+static int test_dropped_hung(struct io_uring *ring)
+{
+	int nr = 10;
+
+	*ring->sq.kdropped = 1000;
+	return run_drained(ring, nr);
+}
+
+int main(int argc, char *argv[])
+{
+	struct io_uring ring, poll_ring, sqthread_ring;
+	struct io_uring_params p;
+	int ret, no_sqthread = 0;
+
+	if (argc > 1)
+		return 0;
+
+	memset(&p, 0, sizeof(p));
+	ret = io_uring_queue_init_params(1000, &ring, &p);
+	if (ret) {
+		printf("ring setup failed\n");
+		return 1;
+	}
+
+	ret = io_uring_queue_init(1000, &poll_ring, IORING_SETUP_IOPOLL);
+	if (ret) {
+		printf("poll_ring setup failed\n");
+		return 1;
+	}
+
+	ret = t_create_ring(1000, &sqthread_ring,
+				IORING_SETUP_SQPOLL | IORING_SETUP_IOPOLL);
+	if (ret == T_SETUP_SKIP)
+		return 0;
+	else if (ret < 0)
+		return 1;
+
+	ret = test_cancelled_userdata(&poll_ring);
+	if (ret) {
+		printf("test_cancelled_userdata failed\n");
+		return ret;
+	}
+
+	if (no_sqthread) {
+		printf("test_thread_link_cancel: skipped, not root\n");
+	} else {
+		ret = test_thread_link_cancel(&sqthread_ring);
+		if (ret) {
+			printf("test_thread_link_cancel failed\n");
+			return ret;
+		}
+	}
+
+	if (!(p.features & IORING_FEAT_NODROP)) {
+		ret = test_overflow_hung(&ring);
+		if (ret) {
+			printf("test_overflow_hung failed\n");
+			return ret;
+		}
+	}
+
+	ret = test_dropped_hung(&ring);
+	if (ret) {
+		printf("test_dropped_hung failed\n");
+		return ret;
+	}
+
+	ret = test_drain_with_linked_timeout(&ring);
+	if (ret) {
+		printf("test_drain_with_linked_timeout failed\n");
+		return ret;
+	}
+
+	return 0;
+}
diff --git a/test/double-poll-crash.c b/test/double-poll-crash.c
new file mode 100644
index 0000000..2a012e5
--- /dev/null
+++ b/test/double-poll-crash.c
@@ -0,0 +1,186 @@
+// https://syzkaller.appspot.com/bug?id=5c9918d20f771265ad0ffae3c8f3859d24850692
+// autogenerated by syzkaller (https://github.com/google/syzkaller)
+
+#include <endian.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+#include "liburing.h"
+#include "../src/syscall.h"
+
+#define SIZEOF_IO_URING_SQE 64
+#define SIZEOF_IO_URING_CQE 16
+#define SQ_HEAD_OFFSET 0
+#define SQ_TAIL_OFFSET 64
+#define SQ_RING_MASK_OFFSET 256
+#define SQ_RING_ENTRIES_OFFSET 264
+#define SQ_FLAGS_OFFSET 276
+#define SQ_DROPPED_OFFSET 272
+#define CQ_HEAD_OFFSET 128
+#define CQ_TAIL_OFFSET 192
+#define CQ_RING_MASK_OFFSET 260
+#define CQ_RING_ENTRIES_OFFSET 268
+#define CQ_RING_OVERFLOW_OFFSET 284
+#define CQ_FLAGS_OFFSET 280
+#define CQ_CQES_OFFSET 320
+
+static long syz_io_uring_setup(volatile long a0, volatile long a1,
+                               volatile long a2, volatile long a3,
+                               volatile long a4, volatile long a5)
+{
+  uint32_t entries = (uint32_t)a0;
+  struct io_uring_params* setup_params = (struct io_uring_params*)a1;
+  void* vma1 = (void*)a2;
+  void* vma2 = (void*)a3;
+  void** ring_ptr_out = (void**)a4;
+  void** sqes_ptr_out = (void**)a5;
+  uint32_t fd_io_uring = __sys_io_uring_setup(entries, setup_params);
+  uint32_t sq_ring_sz =
+      setup_params->sq_off.array + setup_params->sq_entries * sizeof(uint32_t);
+  uint32_t cq_ring_sz = setup_params->cq_off.cqes +
+                        setup_params->cq_entries * SIZEOF_IO_URING_CQE;
+  uint32_t ring_sz = sq_ring_sz > cq_ring_sz ? sq_ring_sz : cq_ring_sz;
+  *ring_ptr_out = mmap(vma1, ring_sz, PROT_READ | PROT_WRITE,
+                       MAP_SHARED | MAP_POPULATE | MAP_FIXED, fd_io_uring,
+                       IORING_OFF_SQ_RING);
+  uint32_t sqes_sz = setup_params->sq_entries * SIZEOF_IO_URING_SQE;
+  *sqes_ptr_out =
+      mmap(vma2, sqes_sz, PROT_READ | PROT_WRITE,
+           MAP_SHARED | MAP_POPULATE | MAP_FIXED, fd_io_uring, IORING_OFF_SQES);
+  return fd_io_uring;
+}
+
+static long syz_io_uring_submit(volatile long a0, volatile long a1,
+                                volatile long a2, volatile long a3)
+{
+  char* ring_ptr = (char*)a0;
+  char* sqes_ptr = (char*)a1;
+  char* sqe = (char*)a2;
+  uint32_t sqes_index = (uint32_t)a3;
+  uint32_t sq_ring_entries = *(uint32_t*)(ring_ptr + SQ_RING_ENTRIES_OFFSET);
+  uint32_t cq_ring_entries = *(uint32_t*)(ring_ptr + CQ_RING_ENTRIES_OFFSET);
+  uint32_t sq_array_off =
+      (CQ_CQES_OFFSET + cq_ring_entries * SIZEOF_IO_URING_CQE + 63) & ~63;
+  if (sq_ring_entries)
+    sqes_index %= sq_ring_entries;
+  char* sqe_dest = sqes_ptr + sqes_index * SIZEOF_IO_URING_SQE;
+  memcpy(sqe_dest, sqe, SIZEOF_IO_URING_SQE);
+  uint32_t sq_ring_mask = *(uint32_t*)(ring_ptr + SQ_RING_MASK_OFFSET);
+  uint32_t* sq_tail_ptr = (uint32_t*)(ring_ptr + SQ_TAIL_OFFSET);
+  uint32_t sq_tail = *sq_tail_ptr & sq_ring_mask;
+  uint32_t sq_tail_next = *sq_tail_ptr + 1;
+  uint32_t* sq_array = (uint32_t*)(ring_ptr + sq_array_off);
+  *(sq_array + sq_tail) = sqes_index;
+  __atomic_store_n(sq_tail_ptr, sq_tail_next, __ATOMIC_RELEASE);
+  return 0;
+}
+
+static long syz_open_dev(volatile long a0, volatile long a1, volatile long a2)
+{
+  if (a0 == 0xc || a0 == 0xb) {
+    char buf[128];
+    sprintf(buf, "/dev/%s/%d:%d", a0 == 0xc ? "char" : "block", (uint8_t)a1,
+            (uint8_t)a2);
+    return open(buf, O_RDWR, 0);
+  } else {
+    char buf[1024];
+    char* hash;
+    strncpy(buf, (char*)a0, sizeof(buf) - 1);
+    buf[sizeof(buf) - 1] = 0;
+    while ((hash = strchr(buf, '#'))) {
+      *hash = '0' + (char)(a1 % 10);
+      a1 /= 10;
+    }
+    return open(buf, a2, 0);
+  }
+}
+
+#ifndef __NR_io_uring_enter
+#define __NR_io_uring_enter 426
+#endif
+
+uint64_t r[4] = {0xffffffffffffffff, 0x0, 0x0, 0xffffffffffffffff};
+
+int main(int argc, char *argv[])
+{
+
+  if (argc > 1)
+    return 0;
+
+  mmap((void *)0x1ffff000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul);
+  mmap((void *)0x20000000ul, 0x1000000ul, 7ul, 0x32ul, -1, 0ul);
+  mmap((void *)0x21000000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul);
+  intptr_t res = 0;
+  *(uint32_t*)0x20000484 = 0;
+  *(uint32_t*)0x20000488 = 0;
+  *(uint32_t*)0x2000048c = 0;
+  *(uint32_t*)0x20000490 = 0;
+  *(uint32_t*)0x20000498 = -1;
+  *(uint32_t*)0x2000049c = 0;
+  *(uint32_t*)0x200004a0 = 0;
+  *(uint32_t*)0x200004a4 = 0;
+  res = -1;
+  res = syz_io_uring_setup(0x6ad4, 0x20000480, 0x20ee7000, 0x20ffb000,
+                           0x20000180, 0x20000040);
+  if (res != -1) {
+    r[0] = res;
+    r[1] = *(uint64_t*)0x20000180;
+    r[2] = *(uint64_t*)0x20000040;
+  }
+  res = -1;
+  res = syz_open_dev(0xc, 4, 0x15);
+  if (res != -1)
+    r[3] = res;
+  *(uint8_t*)0x20000000 = 6;
+  *(uint8_t*)0x20000001 = 0;
+  *(uint16_t*)0x20000002 = 0;
+  *(uint32_t*)0x20000004 = r[3];
+  *(uint64_t*)0x20000008 = 0;
+  *(uint64_t*)0x20000010 = 0;
+  *(uint32_t*)0x20000018 = 0;
+  *(uint16_t*)0x2000001c = 0;
+  *(uint16_t*)0x2000001e = 0;
+  *(uint64_t*)0x20000020 = 0;
+  *(uint16_t*)0x20000028 = 0;
+  *(uint16_t*)0x2000002a = 0;
+  *(uint8_t*)0x2000002c = 0;
+  *(uint8_t*)0x2000002d = 0;
+  *(uint8_t*)0x2000002e = 0;
+  *(uint8_t*)0x2000002f = 0;
+  *(uint8_t*)0x20000030 = 0;
+  *(uint8_t*)0x20000031 = 0;
+  *(uint8_t*)0x20000032 = 0;
+  *(uint8_t*)0x20000033 = 0;
+  *(uint8_t*)0x20000034 = 0;
+  *(uint8_t*)0x20000035 = 0;
+  *(uint8_t*)0x20000036 = 0;
+  *(uint8_t*)0x20000037 = 0;
+  *(uint8_t*)0x20000038 = 0;
+  *(uint8_t*)0x20000039 = 0;
+  *(uint8_t*)0x2000003a = 0;
+  *(uint8_t*)0x2000003b = 0;
+  *(uint8_t*)0x2000003c = 0;
+  *(uint8_t*)0x2000003d = 0;
+  *(uint8_t*)0x2000003e = 0;
+  *(uint8_t*)0x2000003f = 0;
+  syz_io_uring_submit(r[1], r[2], 0x20000000, 0);
+  __sys_io_uring_enter(r[0], 0x20450c, 0, 0ul, 0ul);
+  *(uint32_t*)0x20000080 = 0x7ff;
+  *(uint32_t*)0x20000084 = 0x8b7;
+  *(uint32_t*)0x20000088 = 3;
+  *(uint32_t*)0x2000008c = 0x101;
+  *(uint8_t*)0x20000090 = 9;
+  memcpy((void*)0x20000091, "\xaf\x09\x01\xbc\xf9\xc6\xe4\x92\x86\x51\x7d\x7f"
+                            "\xbd\x43\x7d\x16\x69\x3e\x05",
+         19);
+  ioctl(r[3], 0x5404, 0x20000080ul);
+  return 0;
+}
diff --git a/test/eeed8b54e0df-test.c b/test/eeed8b54e0df-test.c
new file mode 100644
index 0000000..b6e27cc
--- /dev/null
+++ b/test/eeed8b54e0df-test.c
@@ -0,0 +1,119 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: -EAGAIN handling
+ *
+ */
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+
+#include "helpers.h"
+#include "liburing.h"
+
+#define BLOCK	4096
+
+#ifndef RWF_NOWAIT
+#define RWF_NOWAIT	8
+#endif
+
+static int get_file_fd(void)
+{
+	ssize_t ret;
+	char *buf;
+	int fd;
+
+	fd = open("testfile", O_RDWR | O_CREAT, 0644);
+	if (fd < 0) {
+		perror("open file");
+		return -1;
+	}
+
+	buf = t_malloc(BLOCK);
+	ret = write(fd, buf, BLOCK);
+	if (ret != BLOCK) {
+		if (ret < 0)
+			perror("write");
+		else
+			printf("Short write\n");
+		goto err;
+	}
+	fsync(fd);
+
+	if (posix_fadvise(fd, 0, 4096, POSIX_FADV_DONTNEED)) {
+		perror("fadvise");
+err:
+		close(fd);
+		free(buf);
+		return -1;
+	}
+
+	free(buf);
+	return fd;
+}
+
+static void put_file_fd(int fd)
+{
+	close(fd);
+	unlink("testfile");
+}
+
+int main(int argc, char *argv[])
+{
+	struct io_uring ring;
+	struct io_uring_sqe *sqe;
+	struct io_uring_cqe *cqe;
+	struct iovec iov;
+	int ret, fd;
+
+	if (argc > 1)
+		return 0;
+
+	iov.iov_base = t_malloc(4096);
+	iov.iov_len = 4096;
+
+	ret = io_uring_queue_init(2, &ring, 0);
+	if (ret) {
+		printf("ring setup failed\n");
+		return 1;
+
+	}
+
+	sqe = io_uring_get_sqe(&ring);
+	if (!sqe) {
+		printf("get sqe failed\n");
+		return 1;
+	}
+
+	fd = get_file_fd();
+	if (fd < 0)
+		return 1;
+
+	io_uring_prep_readv(sqe, fd, &iov, 1, 0);
+	sqe->rw_flags = RWF_NOWAIT;
+
+	ret = io_uring_submit(&ring);
+	if (ret != 1) {
+		printf("Got submit %d, expected 1\n", ret);
+		goto err;
+	}
+
+	ret = io_uring_peek_cqe(&ring, &cqe);
+	if (ret) {
+		printf("Ring peek got %d\n", ret);
+		goto err;
+	}
+
+	if (cqe->res != -EAGAIN && cqe->res != 4096) {
+		printf("cqe error: %d\n", cqe->res);
+		goto err;
+	}
+
+	put_file_fd(fd);
+	return 0;
+err:
+	put_file_fd(fd);
+	return 1;
+}
diff --git a/test/eventfd-disable.c b/test/eventfd-disable.c
new file mode 100644
index 0000000..f172fd7
--- /dev/null
+++ b/test/eventfd-disable.c
@@ -0,0 +1,151 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: test disable/enable notifications through eventfd
+ *
+ */
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <sys/poll.h>
+#include <sys/eventfd.h>
+
+#include "liburing.h"
+
+int main(int argc, char *argv[])
+{
+	struct io_uring_params p = {};
+	struct io_uring_sqe *sqe;
+	struct io_uring_cqe *cqe;
+	struct io_uring ring;
+	uint64_t ptr;
+	struct iovec vec = {
+		.iov_base = &ptr,
+		.iov_len = sizeof(ptr)
+	};
+	int ret, evfd, i;
+
+	if (argc > 1)
+		return 0;
+
+	ret = io_uring_queue_init_params(64, &ring, &p);
+	if (ret) {
+		fprintf(stderr, "ring setup failed: %d\n", ret);
+		return 1;
+	}
+
+	evfd = eventfd(0, EFD_CLOEXEC);
+	if (evfd < 0) {
+		perror("eventfd");
+		return 1;
+	}
+
+	ret = io_uring_register_eventfd(&ring, evfd);
+	if (ret) {
+		fprintf(stderr, "failed to register evfd: %d\n", ret);
+		return 1;
+	}
+
+	if (!io_uring_cq_eventfd_enabled(&ring)) {
+		fprintf(stderr, "eventfd disabled\n");
+		return 1;
+	}
+
+	ret = io_uring_cq_eventfd_toggle(&ring, false);
+	if (ret) {
+		fprintf(stdout, "Skipping, CQ flags not available!\n");
+		return 0;
+	}
+
+	sqe = io_uring_get_sqe(&ring);
+	io_uring_prep_readv(sqe, evfd, &vec, 1, 0);
+	sqe->user_data = 1;
+
+	ret = io_uring_submit(&ring);
+	if (ret != 1) {
+		fprintf(stderr, "submit: %d\n", ret);
+		return 1;
+	}
+
+	for (i = 0; i < 63; i++) {
+		sqe = io_uring_get_sqe(&ring);
+		io_uring_prep_nop(sqe);
+		sqe->user_data = 2;
+	}
+
+	ret = io_uring_submit(&ring);
+	if (ret != 63) {
+		fprintf(stderr, "submit: %d\n", ret);
+		return 1;
+	}
+
+	for (i = 0; i < 63; i++) {
+		ret = io_uring_wait_cqe(&ring, &cqe);
+		if (ret) {
+			fprintf(stderr, "wait: %d\n", ret);
+			return 1;
+		}
+
+		switch (cqe->user_data) {
+		case 1: /* eventfd */
+			fprintf(stderr, "eventfd unexpected: %d\n", (int)ptr);
+			return 1;
+		case 2:
+			if (cqe->res) {
+				fprintf(stderr, "nop: %d\n", cqe->res);
+				return 1;
+			}
+			break;
+		}
+		io_uring_cqe_seen(&ring, cqe);
+	}
+
+	ret = io_uring_cq_eventfd_toggle(&ring, true);
+	if (ret) {
+		fprintf(stderr, "io_uring_cq_eventfd_toggle: %d\n", ret);
+		return 1;
+	}
+
+	sqe = io_uring_get_sqe(&ring);
+	io_uring_prep_nop(sqe);
+	sqe->user_data = 2;
+
+	ret = io_uring_submit(&ring);
+	if (ret != 1) {
+		fprintf(stderr, "submit: %d\n", ret);
+		return 1;
+	}
+
+	for (i = 0; i < 2; i++) {
+		ret = io_uring_wait_cqe(&ring, &cqe);
+		if (ret) {
+			fprintf(stderr, "wait: %d\n", ret);
+			return 1;
+		}
+
+		switch (cqe->user_data) {
+		case 1: /* eventfd */
+			if (cqe->res != sizeof(ptr)) {
+				fprintf(stderr, "read res: %d\n", cqe->res);
+				return 1;
+			}
+
+			if (ptr != 1) {
+				fprintf(stderr, "eventfd: %d\n", (int)ptr);
+				return 1;
+			}
+			break;
+		case 2:
+			if (cqe->res) {
+				fprintf(stderr, "nop: %d\n", cqe->res);
+				return 1;
+			}
+			break;
+		}
+		io_uring_cqe_seen(&ring, cqe);
+	}
+
+	return 0;
+}
diff --git a/test/eventfd-ring.c b/test/eventfd-ring.c
new file mode 100644
index 0000000..67e102c
--- /dev/null
+++ b/test/eventfd-ring.c
@@ -0,0 +1,97 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: run various nop tests
+ *
+ */
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <sys/poll.h>
+#include <sys/eventfd.h>
+
+#include "liburing.h"
+
+int main(int argc, char *argv[])
+{
+	struct io_uring_params p = {};
+	struct io_uring ring1, ring2;
+	struct io_uring_sqe *sqe;
+	int ret, evfd1, evfd2;
+
+	if (argc > 1)
+		return 0;
+
+	ret = io_uring_queue_init_params(8, &ring1, &p);
+	if (ret) {
+		fprintf(stderr, "ring setup failed: %d\n", ret);
+		return 1;
+	}
+	if (!(p.features & IORING_FEAT_CUR_PERSONALITY)) {
+		fprintf(stdout, "Skipping\n");
+		return 0;
+	}
+	ret = io_uring_queue_init(8, &ring2, 0);
+	if (ret) {
+		fprintf(stderr, "ring setup failed: %d\n", ret);
+		return 1;
+	}
+
+	evfd1 = eventfd(0, EFD_CLOEXEC);
+	if (evfd1 < 0) {
+		perror("eventfd");
+		return 1;
+	}
+
+	evfd2 = eventfd(0, EFD_CLOEXEC);
+	if (evfd2 < 0) {
+		perror("eventfd");
+		return 1;
+	}
+
+	ret = io_uring_register_eventfd(&ring1, evfd1);
+	if (ret) {
+		fprintf(stderr, "failed to register evfd: %d\n", ret);
+		return 1;
+	}
+
+	ret = io_uring_register_eventfd(&ring2, evfd2);
+	if (ret) {
+		fprintf(stderr, "failed to register evfd: %d\n", ret);
+		return 1;
+	}
+
+	sqe = io_uring_get_sqe(&ring1);
+	io_uring_prep_poll_add(sqe, evfd2, POLLIN);
+	sqe->user_data = 1;
+
+	sqe = io_uring_get_sqe(&ring2);
+	io_uring_prep_poll_add(sqe, evfd1, POLLIN);
+	sqe->user_data = 1;
+
+	ret = io_uring_submit(&ring1);
+	if (ret != 1) {
+		fprintf(stderr, "submit: %d\n", ret);
+		return 1;
+	}
+
+	ret = io_uring_submit(&ring2);
+	if (ret != 1) {
+		fprintf(stderr, "submit: %d\n", ret);
+		return 1;
+	}
+
+	sqe = io_uring_get_sqe(&ring1);
+	io_uring_prep_nop(sqe);
+	sqe->user_data = 3;
+
+	ret = io_uring_submit(&ring1);
+	if (ret != 1) {
+		fprintf(stderr, "submit: %d\n", ret);
+		return 1;
+	}
+
+	return 0;
+}
diff --git a/test/eventfd.c b/test/eventfd.c
new file mode 100644
index 0000000..1a7e3f3
--- /dev/null
+++ b/test/eventfd.c
@@ -0,0 +1,112 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: run various nop tests
+ *
+ */
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <sys/poll.h>
+#include <sys/eventfd.h>
+
+#include "liburing.h"
+
+int main(int argc, char *argv[])
+{
+	struct io_uring_params p = {};
+	struct io_uring_sqe *sqe;
+	struct io_uring_cqe *cqe;
+	struct io_uring ring;
+	uint64_t ptr;
+	struct iovec vec = {
+		.iov_base = &ptr,
+		.iov_len = sizeof(ptr)
+	};
+	int ret, evfd, i;
+
+	if (argc > 1)
+		return 0;
+
+	ret = io_uring_queue_init_params(8, &ring, &p);
+	if (ret) {
+		fprintf(stderr, "ring setup failed: %d\n", ret);
+		return 1;
+	}
+	if (!(p.features & IORING_FEAT_CUR_PERSONALITY)) {
+		fprintf(stdout, "Skipping\n");
+		return 0;
+	}
+
+	evfd = eventfd(0, EFD_CLOEXEC);
+	if (evfd < 0) {
+		perror("eventfd");
+		return 1;
+	}
+
+	ret = io_uring_register_eventfd(&ring, evfd);
+	if (ret) {
+		fprintf(stderr, "failed to register evfd: %d\n", ret);
+		return 1;
+	}
+
+	sqe = io_uring_get_sqe(&ring);
+	io_uring_prep_poll_add(sqe, evfd, POLLIN);
+	sqe->flags |= IOSQE_IO_LINK;
+	sqe->user_data = 1;
+
+	sqe = io_uring_get_sqe(&ring);
+	io_uring_prep_readv(sqe, evfd, &vec, 1, 0);
+	sqe->flags |= IOSQE_IO_LINK;
+	sqe->user_data = 2;
+
+	ret = io_uring_submit(&ring);
+	if (ret != 2) {
+		fprintf(stderr, "submit: %d\n", ret);
+		return 1;
+	}
+
+	sqe = io_uring_get_sqe(&ring);
+	io_uring_prep_nop(sqe);
+	sqe->user_data = 3;
+
+	ret = io_uring_submit(&ring);
+	if (ret != 1) {
+		fprintf(stderr, "submit: %d\n", ret);
+		return 1;
+	}
+
+	for (i = 0; i < 3; i++) {
+		ret = io_uring_wait_cqe(&ring, &cqe);
+		if (ret) {
+			fprintf(stderr, "wait: %d\n", ret);
+			return 1;
+		}
+		switch (cqe->user_data) {
+		case 1:
+			/* POLLIN */
+			if (cqe->res != 1) {
+				fprintf(stderr, "poll: %d\n", cqe->res);
+				return 1;
+			}
+			break;
+		case 2:
+			if (cqe->res != sizeof(ptr)) {
+				fprintf(stderr, "read: %d\n", cqe->res);
+				return 1;
+			}
+			break;
+		case 3:
+			if (cqe->res) {
+				fprintf(stderr, "nop: %d\n", cqe->res);
+				return 1;
+			}
+			break;
+		}
+		io_uring_cqe_seen(&ring, cqe);
+	}
+
+	return 0;
+}
diff --git a/test/fadvise.c b/test/fadvise.c
new file mode 100644
index 0000000..b6d4462
--- /dev/null
+++ b/test/fadvise.c
@@ -0,0 +1,200 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: basic fadvise test
+ */
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/time.h>
+
+#include "helpers.h"
+#include "liburing.h"
+
+#define FILE_SIZE	(128 * 1024)
+#define LOOPS		100
+#define MIN_LOOPS	10
+
+static unsigned long long utime_since(const struct timeval *s,
+				      const struct timeval *e)
+{
+	long long sec, usec;
+
+	sec = e->tv_sec - s->tv_sec;
+	usec = (e->tv_usec - s->tv_usec);
+	if (sec > 0 && usec < 0) {
+		sec--;
+		usec += 1000000;
+	}
+
+	sec *= 1000000;
+	return sec + usec;
+}
+
+static unsigned long long utime_since_now(struct timeval *tv)
+{
+	struct timeval end;
+
+	gettimeofday(&end, NULL);
+	return utime_since(tv, &end);
+}
+
+static int do_fadvise(struct io_uring *ring, int fd, off_t offset, off_t len,
+		      int advice)
+{
+	struct io_uring_sqe *sqe;
+	struct io_uring_cqe *cqe;
+	int ret;
+
+	sqe = io_uring_get_sqe(ring);
+	if (!sqe) {
+		fprintf(stderr, "failed to get sqe\n");
+		return 1;
+	}
+
+	io_uring_prep_fadvise(sqe, fd, offset, len, advice);
+	sqe->user_data = advice;
+	ret = io_uring_submit_and_wait(ring, 1);
+	if (ret != 1) {
+		fprintf(stderr, "submit: %d\n", ret);
+		return 1;
+	}
+
+	ret = io_uring_wait_cqe(ring, &cqe);
+	if (ret) {
+		fprintf(stderr, "wait: %d\n", ret);
+		return 1;
+	}
+
+	ret = cqe->res;
+	if (ret == -EINVAL || ret == -EBADF) {
+		fprintf(stdout, "Fadvise not supported, skipping\n");
+		unlink(".fadvise.tmp");
+		exit(0);
+	} else if (ret) {
+		fprintf(stderr, "cqe->res=%d\n", cqe->res);
+	}
+	io_uring_cqe_seen(ring, cqe);
+	return ret;
+}
+
+static long do_read(int fd, char *buf)
+{
+	struct timeval tv;
+	int ret;
+	long t;
+
+	ret = lseek(fd, 0, SEEK_SET);
+	if (ret) {
+		perror("lseek");
+		return -1;
+	}
+	
+	gettimeofday(&tv, NULL);
+	ret = read(fd, buf, FILE_SIZE);
+	t = utime_since_now(&tv);
+	if (ret < 0) {
+		perror("read");
+		return -1;
+	} else if (ret != FILE_SIZE) {
+		fprintf(stderr, "short read1: %d\n", ret);
+		return -1;
+	}
+
+	return t;
+}
+
+static int test_fadvise(struct io_uring *ring, const char *filename)
+{
+	unsigned long cached_read, uncached_read, cached_read2;
+	int fd, ret;
+	char *buf;
+
+	fd = open(filename, O_RDONLY);
+	if (fd < 0) {
+		perror("open");
+		return 1;
+	}
+
+	buf = t_malloc(FILE_SIZE);
+
+	cached_read = do_read(fd, buf);
+	if (cached_read == -1)
+		return 1;
+
+	ret = do_fadvise(ring, fd, 0, FILE_SIZE, POSIX_FADV_DONTNEED);
+	if (ret)
+		return 1;
+
+	uncached_read = do_read(fd, buf);
+	if (uncached_read == -1)
+		return 1;
+
+	ret = do_fadvise(ring, fd, 0, FILE_SIZE, POSIX_FADV_DONTNEED);
+	if (ret)
+		return 1;
+
+	ret = do_fadvise(ring, fd, 0, FILE_SIZE, POSIX_FADV_WILLNEED);
+	if (ret)
+		return 1;
+
+	fsync(fd);
+
+	cached_read2 = do_read(fd, buf);
+	if (cached_read2 == -1)
+		return 1;
+
+	if (cached_read < uncached_read &&
+	    cached_read2 < uncached_read)
+		return 0;
+
+	return 2;
+}
+
+int main(int argc, char *argv[])
+{
+	struct io_uring ring;
+	int ret, i, good, bad;
+	char *fname;
+
+	if (argc > 1) {
+		fname = argv[1];
+	} else {
+		fname = ".fadvise.tmp";
+		t_create_file(fname, FILE_SIZE);
+	}
+	if (io_uring_queue_init(8, &ring, 0)) {
+		fprintf(stderr, "ring creation failed\n");
+		goto err;
+	}
+
+	good = bad = 0;
+	for (i = 0; i < LOOPS; i++) {
+		ret = test_fadvise(&ring, fname);
+		if (ret == 1) {
+			fprintf(stderr, "read_fadvise failed\n");
+			goto err;
+		} else if (!ret)
+			good++;
+		else if (ret == 2)
+			bad++;
+		if (i >= MIN_LOOPS && !bad)
+			break;
+	}
+	if (bad > good) {
+		fprintf(stderr, "Suspicious timings\n");
+		goto err;
+	}
+
+	if (fname != argv[1])
+		unlink(fname);
+	io_uring_queue_exit(&ring);
+	return 0;
+err:
+	if (fname != argv[1])
+		unlink(fname);
+	return 1;
+}
diff --git a/test/fallocate.c b/test/fallocate.c
new file mode 100644
index 0000000..da90be8
--- /dev/null
+++ b/test/fallocate.c
@@ -0,0 +1,252 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: test io_uring fallocate
+ *
+ */
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/resource.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+
+#include "liburing.h"
+
+static int no_fallocate;
+
+static int test_fallocate_rlimit(struct io_uring *ring)
+{
+	struct io_uring_cqe *cqe;
+	struct io_uring_sqe *sqe;
+	struct rlimit rlim;
+	char buf[32];
+	int fd, ret;
+
+	if (getrlimit(RLIMIT_FSIZE, &rlim) < 0) {
+		perror("getrlimit");
+		return 1;
+	}
+	rlim.rlim_cur = 64 * 1024;
+	rlim.rlim_max = 64 * 1024;
+	if (setrlimit(RLIMIT_FSIZE, &rlim) < 0) {
+		perror("setrlimit");
+		return 1;
+	}
+
+	sprintf(buf, "./XXXXXX");
+	fd = mkstemp(buf);
+	if (fd < 0) {
+		perror("open");
+		return 1;
+	}
+
+	sqe = io_uring_get_sqe(ring);
+	if (!sqe) {
+		fprintf(stderr, "get sqe failed\n");
+		goto err;
+	}
+	io_uring_prep_fallocate(sqe, fd, 0, 0, 128*1024);
+
+	ret = io_uring_submit(ring);
+	if (ret <= 0) {
+		fprintf(stderr, "sqe submit failed: %d\n", ret);
+		goto err;
+	}
+
+	ret = io_uring_wait_cqe(ring, &cqe);
+	if (ret < 0) {
+		fprintf(stderr, "wait completion %d\n", ret);
+		goto err;
+	}
+
+	if (cqe->res == -EINVAL) {
+		fprintf(stdout, "Fallocate not supported, skipping\n");
+		no_fallocate = 1;
+		goto out;
+	} else if (cqe->res != -EFBIG) {
+		fprintf(stderr, "Expected -EFBIG: %d\n", cqe->res);
+		goto err;
+	}
+	io_uring_cqe_seen(ring, cqe);
+out:
+	unlink(buf);
+	return 0;
+err:
+	unlink(buf);
+	return 1;
+}
+
+static int test_fallocate(struct io_uring *ring)
+{
+	struct io_uring_cqe *cqe;
+	struct io_uring_sqe *sqe;
+	struct stat st;
+	char buf[32];
+	int fd, ret;
+
+	sprintf(buf, "./XXXXXX");
+	fd = mkstemp(buf);
+	if (fd < 0) {
+		perror("open");
+		return 1;
+	}
+
+	sqe = io_uring_get_sqe(ring);
+	if (!sqe) {
+		fprintf(stderr, "get sqe failed\n");
+		goto err;
+	}
+	io_uring_prep_fallocate(sqe, fd, 0, 0, 128*1024);
+
+	ret = io_uring_submit(ring);
+	if (ret <= 0) {
+		fprintf(stderr, "sqe submit failed: %d\n", ret);
+		goto err;
+	}
+
+	ret = io_uring_wait_cqe(ring, &cqe);
+	if (ret < 0) {
+		fprintf(stderr, "wait completion %d\n", ret);
+		goto err;
+	}
+
+	if (cqe->res == -EINVAL) {
+		fprintf(stdout, "Fallocate not supported, skipping\n");
+		no_fallocate = 1;
+		goto out;
+	}
+	if (cqe->res) {
+		fprintf(stderr, "cqe->res=%d\n", cqe->res);
+		goto err;
+	}
+	io_uring_cqe_seen(ring, cqe);
+
+	if (fstat(fd, &st) < 0) {
+		perror("stat");
+		goto err;
+	}
+
+	if (st.st_size != 128*1024) {
+		fprintf(stderr, "Size mismatch: %llu\n",
+					(unsigned long long) st.st_size);
+		goto err;
+	}
+
+out:
+	unlink(buf);
+	return 0;
+err:
+	unlink(buf);
+	return 1;
+}
+
+static int test_fallocate_fsync(struct io_uring *ring)
+{
+	struct io_uring_cqe *cqe;
+	struct io_uring_sqe *sqe;
+	struct stat st;
+	char buf[32];
+	int fd, ret, i;
+
+	if (no_fallocate)
+		return 0;
+
+	sprintf(buf, "./XXXXXX");
+	fd = mkstemp(buf);
+	if (fd < 0) {
+		perror("open");
+		return 1;
+	}
+
+	sqe = io_uring_get_sqe(ring);
+	if (!sqe) {
+		fprintf(stderr, "get sqe failed\n");
+		goto err;
+	}
+	io_uring_prep_fallocate(sqe, fd, 0, 0, 128*1024);
+	sqe->flags |= IOSQE_IO_LINK;
+	sqe->user_data = 1;
+
+	sqe = io_uring_get_sqe(ring);
+	if (!sqe) {
+		fprintf(stderr, "get sqe failed\n");
+		goto err;
+	}
+	io_uring_prep_fsync(sqe, fd, 0);
+	sqe->user_data = 2;
+
+	ret = io_uring_submit(ring);
+	if (ret <= 0) {
+		fprintf(stderr, "sqe submit failed: %d\n", ret);
+		goto err;
+	}
+
+	for (i = 0; i < 2; i++) {
+		ret = io_uring_wait_cqe(ring, &cqe);
+		if (ret < 0) {
+			fprintf(stderr, "wait completion %d\n", ret);
+			goto err;
+		}
+		if (cqe->res) {
+			fprintf(stderr, "cqe->res=%d,data=%" PRIu64 "\n", cqe->res,
+							(uint64_t) cqe->user_data);
+			goto err;
+		}
+		io_uring_cqe_seen(ring, cqe);
+	}
+
+	if (fstat(fd, &st) < 0) {
+		perror("stat");
+		goto err;
+	}
+
+	if (st.st_size != 128*1024) {
+		fprintf(stderr, "Size mismatch: %llu\n",
+					(unsigned long long) st.st_size);
+		goto err;
+	}
+
+	unlink(buf);
+	return 0;
+err:
+	unlink(buf);
+	return 1;
+}
+
+int main(int argc, char *argv[])
+{
+	struct io_uring ring;
+	int ret;
+
+	if (argc > 1)
+		return 0;
+
+	ret = io_uring_queue_init(8, &ring, 0);
+	if (ret) {
+		fprintf(stderr, "ring setup failed\n");
+		return 1;
+	}
+
+	ret = test_fallocate(&ring);
+	if (ret) {
+		fprintf(stderr, "test_fallocate failed\n");
+		return ret;
+	}
+
+	ret = test_fallocate_fsync(&ring);
+	if (ret) {
+		fprintf(stderr, "test_fallocate_fsync failed\n");
+		return ret;
+	}
+
+	ret = test_fallocate_rlimit(&ring);
+	if (ret) {
+		fprintf(stderr, "test_fallocate_rlimit failed\n");
+		return ret;
+	}
+
+	return 0;
+}
diff --git a/test/fc2a85cb02ef-test.c b/test/fc2a85cb02ef-test.c
new file mode 100644
index 0000000..35addf5
--- /dev/null
+++ b/test/fc2a85cb02ef-test.c
@@ -0,0 +1,138 @@
+/* SPDX-License-Identifier: MIT */
+// https://syzkaller.appspot.com/bug?id=1f2ecd7a23dba87e5ca3505ec44514a462cfe8c0
+// autogenerated by syzkaller (https://github.com/google/syzkaller)
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+#include "liburing.h"
+#include "../src/syscall.h"
+
+static bool write_file(const char* file, const char* what, ...)
+{
+  char buf[1024];
+  va_list args;
+  va_start(args, what);
+  vsnprintf(buf, sizeof(buf), what, args);
+  va_end(args);
+  buf[sizeof(buf) - 1] = 0;
+  int len = strlen(buf);
+  int fd = open(file, O_WRONLY | O_CLOEXEC);
+  if (fd == -1)
+    return false;
+  if (write(fd, buf, len) != len) {
+    int err = errno;
+    close(fd);
+    errno = err;
+    return false;
+  }
+  close(fd);
+  return true;
+}
+
+static int inject_fault(int nth)
+{
+  int fd;
+  fd = open("/proc/thread-self/fail-nth", O_RDWR);
+  if (fd == -1)
+    exit(1);
+  char buf[16];
+  sprintf(buf, "%d", nth + 1);
+  if (write(fd, buf, strlen(buf)) != (ssize_t)strlen(buf))
+    exit(1);
+  return fd;
+}
+
+static int setup_fault()
+{
+  static struct {
+    const char* file;
+    const char* val;
+    bool fatal;
+  } files[] = {
+      {"/sys/kernel/debug/failslab/ignore-gfp-wait", "N", true},
+      {"/sys/kernel/debug/failslab/verbose", "0", false},
+      {"/sys/kernel/debug/fail_futex/ignore-private", "N", false},
+      {"/sys/kernel/debug/fail_page_alloc/verbose", "0", false},
+      {"/sys/kernel/debug/fail_page_alloc/ignore-gfp-highmem", "N", false},
+      {"/sys/kernel/debug/fail_page_alloc/ignore-gfp-wait", "N", false},
+      {"/sys/kernel/debug/fail_page_alloc/min-order", "0", false},
+  };
+  unsigned i;
+  for (i = 0; i < sizeof(files) / sizeof(files[0]); i++) {
+    if (!write_file(files[i].file, files[i].val)) {
+      if (files[i].fatal)
+	return 1;
+    }
+  }
+  return 0;
+}
+
+#ifndef __NR_io_uring_register
+#define __NR_io_uring_register 427
+#endif
+#ifndef __NR_io_uring_setup
+#define __NR_io_uring_setup 425
+#endif
+
+uint64_t r[2] = {0xffffffffffffffff, 0xffffffffffffffff};
+
+int main(int argc, char *argv[])
+{
+  if (argc > 1)
+    return 0;
+  mmap((void *) 0x20000000ul, 0x1000000ul, 3ul, 0x32ul, -1, 0);
+  if (setup_fault()) {
+    printf("Test needs failslab/fail_futex/fail_page_alloc enabled, skipped\n");
+    return 0;
+  }
+  intptr_t res = 0;
+  *(uint32_t*)0x20000000 = 0;
+  *(uint32_t*)0x20000004 = 0;
+  *(uint32_t*)0x20000008 = 0;
+  *(uint32_t*)0x2000000c = 0;
+  *(uint32_t*)0x20000010 = 0;
+  *(uint32_t*)0x20000014 = 0;
+  *(uint32_t*)0x20000018 = 0;
+  *(uint32_t*)0x2000001c = 0;
+  *(uint32_t*)0x20000020 = 0;
+  *(uint32_t*)0x20000024 = 0;
+  *(uint32_t*)0x20000028 = 0;
+  *(uint32_t*)0x2000002c = 0;
+  *(uint32_t*)0x20000030 = 0;
+  *(uint32_t*)0x20000034 = 0;
+  *(uint32_t*)0x20000038 = 0;
+  *(uint32_t*)0x2000003c = 0;
+  *(uint32_t*)0x20000040 = 0;
+  *(uint32_t*)0x20000044 = 0;
+  *(uint64_t*)0x20000048 = 0;
+  *(uint32_t*)0x20000050 = 0;
+  *(uint32_t*)0x20000054 = 0;
+  *(uint32_t*)0x20000058 = 0;
+  *(uint32_t*)0x2000005c = 0;
+  *(uint32_t*)0x20000060 = 0;
+  *(uint32_t*)0x20000064 = 0;
+  *(uint32_t*)0x20000068 = 0;
+  *(uint32_t*)0x2000006c = 0;
+  *(uint64_t*)0x20000070 = 0;
+  res = __sys_io_uring_setup(0x6a6, (struct io_uring_params *) 0x20000000ul);
+  if (res != -1)
+    r[0] = res;
+  res = socket(0x11ul, 2ul, 0x300ul);
+  if (res != -1)
+    r[1] = res;
+  *(uint32_t*)0x20000080 = r[1];
+  inject_fault(1);
+  __sys_io_uring_register(r[0], 2ul, (const void *) 0x20000080ul, 1ul);
+  return 0;
+}
diff --git a/test/file-register.c b/test/file-register.c
new file mode 100644
index 0000000..c5c5507
--- /dev/null
+++ b/test/file-register.c
@@ -0,0 +1,842 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: run various file registration tests
+ *
+ */
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+
+#include "helpers.h"
+#include "liburing.h"
+
+static int no_update = 0;
+
+static void close_files(int *files, int nr_files, int add)
+{
+	char fname[32];
+	int i;
+
+	for (i = 0; i < nr_files; i++) {
+		if (files)
+			close(files[i]);
+		if (!add)
+			sprintf(fname, ".reg.%d", i);
+		else
+			sprintf(fname, ".add.%d", i + add);
+		unlink(fname);
+	}
+	if (files)
+		free(files);
+}
+
+static int *open_files(int nr_files, int extra, int add)
+{
+	char fname[32];
+	int *files;
+	int i;
+
+	files = t_calloc(nr_files + extra, sizeof(int));
+
+	for (i = 0; i < nr_files; i++) {
+		if (!add)
+			sprintf(fname, ".reg.%d", i);
+		else
+			sprintf(fname, ".add.%d", i + add);
+		files[i] = open(fname, O_RDWR | O_CREAT, 0644);
+		if (files[i] < 0) {
+			perror("open");
+			free(files);
+			files = NULL;
+			break;
+		}
+	}
+	if (extra) {
+		for (i = nr_files; i < nr_files + extra; i++)
+			files[i] = -1;
+	}
+
+	return files;
+}
+
+static int test_shrink(struct io_uring *ring)
+{
+	int ret, off, fd;
+	int *files;
+
+	files = open_files(50, 0, 0);
+	ret = io_uring_register_files(ring, files, 50);
+	if (ret) {
+		fprintf(stderr, "%s: register ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+
+	off = 0;
+	do {
+		fd = -1;
+		ret = io_uring_register_files_update(ring, off, &fd, 1);
+		if (ret != 1) {
+			if (off == 50 && ret == -EINVAL)
+				break;
+			fprintf(stderr, "%s: update ret=%d\n", __FUNCTION__, ret);
+			break;
+		}
+		off++;
+	} while (1);
+
+	ret = io_uring_unregister_files(ring);
+	if (ret) {
+		fprintf(stderr, "%s: unregister ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+
+	close_files(files, 50, 0);
+	return 0;
+err:
+	close_files(files, 50, 0);
+	return 1;
+}
+
+
+static int test_grow(struct io_uring *ring)
+{
+	int ret, off;
+	int *files, *fds = NULL;
+
+	files = open_files(50, 250, 0);
+	ret = io_uring_register_files(ring, files, 300);
+	if (ret) {
+		fprintf(stderr, "%s: register ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+
+	off = 50;
+	do {
+		fds = open_files(1, 0, off);
+		ret = io_uring_register_files_update(ring, off, fds, 1);
+		if (ret != 1) {
+			if (off == 300 && ret == -EINVAL)
+				break;
+			fprintf(stderr, "%s: update ret=%d\n", __FUNCTION__, ret);
+			break;
+		}
+		if (off >= 300) {
+			fprintf(stderr, "%s: Succeeded beyond end-of-list?\n", __FUNCTION__);
+			goto err;
+		}
+		off++;
+	} while (1);
+
+	ret = io_uring_unregister_files(ring);
+	if (ret) {
+		fprintf(stderr, "%s: unregister ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+
+	close_files(files, 100, 0);
+	close_files(NULL, 251, 50);
+	return 0;
+err:
+	close_files(files, 100, 0);
+	close_files(NULL, 251, 50);
+	return 1;
+}
+
+static int test_replace_all(struct io_uring *ring)
+{
+	int *files, *fds = NULL;
+	int ret, i;
+
+	files = open_files(100, 0, 0);
+	ret = io_uring_register_files(ring, files, 100);
+	if (ret) {
+		fprintf(stderr, "%s: register ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+
+	fds = t_malloc(100 * sizeof(int));
+	for (i = 0; i < 100; i++)
+		fds[i] = -1;
+
+	ret = io_uring_register_files_update(ring, 0, fds, 100);
+	if (ret != 100) {
+		fprintf(stderr, "%s: update ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+
+	ret = io_uring_unregister_files(ring);
+	if (ret) {
+		fprintf(stderr, "%s: unregister ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+
+	close_files(files, 100, 0);
+	if (fds)
+		free(fds);
+	return 0;
+err:
+	close_files(files, 100, 0);
+	if (fds)
+		free(fds);
+	return 1;
+}
+
+static int test_replace(struct io_uring *ring)
+{
+	int *files, *fds = NULL;
+	int ret;
+
+	files = open_files(100, 0, 0);
+	ret = io_uring_register_files(ring, files, 100);
+	if (ret) {
+		fprintf(stderr, "%s: register ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+
+	fds = open_files(10, 0, 1);
+	ret = io_uring_register_files_update(ring, 90, fds, 10);
+	if (ret != 10) {
+		fprintf(stderr, "%s: update ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+
+	ret = io_uring_unregister_files(ring);
+	if (ret) {
+		fprintf(stderr, "%s: unregister ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+
+	close_files(files, 100, 0);
+	if (fds)
+		close_files(fds, 10, 1);
+	return 0;
+err:
+	close_files(files, 100, 0);
+	if (fds)
+		close_files(fds, 10, 1);
+	return 1;
+}
+
+static int test_removals(struct io_uring *ring)
+{
+	int *files, *fds = NULL;
+	int ret, i;
+
+	files = open_files(100, 0, 0);
+	ret = io_uring_register_files(ring, files, 100);
+	if (ret) {
+		fprintf(stderr, "%s: register ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+
+	fds = t_calloc(10, sizeof(int));
+	for (i = 0; i < 10; i++)
+		fds[i] = -1;
+
+	ret = io_uring_register_files_update(ring, 50, fds, 10);
+	if (ret != 10) {
+		fprintf(stderr, "%s: update ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+
+	ret = io_uring_unregister_files(ring);
+	if (ret) {
+		fprintf(stderr, "%s: unregister ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+
+	close_files(files, 100, 0);
+	if (fds)
+		free(fds);
+	return 0;
+err:
+	close_files(files, 100, 0);
+	if (fds)
+		free(fds);
+	return 1;
+}
+
+static int test_additions(struct io_uring *ring)
+{
+	int *files, *fds = NULL;
+	int ret;
+
+	files = open_files(100, 100, 0);
+	ret = io_uring_register_files(ring, files, 200);
+	if (ret) {
+		fprintf(stderr, "%s: register ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+
+	fds = open_files(2, 0, 1);
+	ret = io_uring_register_files_update(ring, 100, fds, 2);
+	if (ret != 2) {
+		fprintf(stderr, "%s: update ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+
+	ret = io_uring_unregister_files(ring);
+	if (ret) {
+		fprintf(stderr, "%s: unregister ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+
+	close_files(files, 100, 0);
+	if (fds)
+		close_files(fds, 2, 1);
+	return 0;
+err:
+	close_files(files, 100, 0);
+	if (fds)
+		close_files(fds, 2, 1);
+	return 1;
+}
+
+static int test_sparse(struct io_uring *ring)
+{
+	int *files;
+	int ret;
+
+	files = open_files(100, 100, 0);
+	ret = io_uring_register_files(ring, files, 200);
+	if (ret) {
+		if (ret == -EBADF) {
+			fprintf(stdout, "Sparse files not supported\n");
+			no_update = 1;
+			goto done;
+		}
+		fprintf(stderr, "%s: register ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+	ret = io_uring_unregister_files(ring);
+	if (ret) {
+		fprintf(stderr, "%s: unregister ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+done:
+	close_files(files, 100, 0);
+	return 0;
+err:
+	close_files(files, 100, 0);
+	return 1;
+}
+
+static int test_basic_many(struct io_uring *ring)
+{
+	int *files;
+	int ret;
+
+	files = open_files(768, 0, 0);
+	ret = io_uring_register_files(ring, files, 768);
+	if (ret) {
+		fprintf(stderr, "%s: register %d\n", __FUNCTION__, ret);
+		goto err;
+	}
+	ret = io_uring_unregister_files(ring);
+	if (ret) {
+		fprintf(stderr, "%s: unregister %d\n", __FUNCTION__, ret);
+		goto err;
+	}
+	close_files(files, 768, 0);
+	return 0;
+err:
+	close_files(files, 768, 0);
+	return 1;
+}
+
+static int test_basic(struct io_uring *ring, int fail)
+{
+	int *files;
+	int ret;
+
+	files = open_files(fail ? 10 : 100, 0, 0);
+	ret = io_uring_register_files(ring, files, 100);
+	if (ret) {
+		if (fail) {
+			if (ret == -EBADF || ret == -EFAULT)
+				return 0;
+		}
+		fprintf(stderr, "%s: register %d\n", __FUNCTION__, ret);
+		goto err;
+	}
+	if (fail) {
+		fprintf(stderr, "Registration succeeded, but expected fail\n");
+		goto err;
+	}
+	ret = io_uring_unregister_files(ring);
+	if (ret) {
+		fprintf(stderr, "%s: unregister %d\n", __FUNCTION__, ret);
+		goto err;
+	}
+	close_files(files, 100, 0);
+	return 0;
+err:
+	close_files(files, 100, 0);
+	return 1;
+}
+
+/*
+ * Register 0 files, but reserve space for 10.  Then add one file.
+ */
+static int test_zero(struct io_uring *ring)
+{
+	int *files, *fds = NULL;
+	int ret;
+
+	files = open_files(0, 10, 0);
+	ret = io_uring_register_files(ring, files, 10);
+	if (ret) {
+		fprintf(stderr, "%s: register ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+
+	fds = open_files(1, 0, 1);
+	ret = io_uring_register_files_update(ring, 0, fds, 1);
+	if (ret != 1) {
+		fprintf(stderr, "%s: update ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+
+	ret = io_uring_unregister_files(ring);
+	if (ret) {
+		fprintf(stderr, "%s: unregister ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+
+	if (fds)
+		close_files(fds, 1, 1);
+	free(files);
+	return 0;
+err:
+	if (fds)
+		close_files(fds, 1, 1);
+	free(files);
+	return 1;
+}
+
+static int test_fixed_read_write(struct io_uring *ring, int index)
+{
+	struct io_uring_sqe *sqe;
+	struct io_uring_cqe *cqe;
+	struct iovec iov[2];
+	int ret;
+
+	iov[0].iov_base = t_malloc(4096);
+	iov[0].iov_len = 4096;
+	memset(iov[0].iov_base, 0x5a, 4096);
+
+	iov[1].iov_base = t_malloc(4096);
+	iov[1].iov_len = 4096;
+
+	sqe = io_uring_get_sqe(ring);
+	if (!sqe) {
+		fprintf(stderr, "%s: failed to get sqe\n", __FUNCTION__);
+		return 1;
+	}
+	io_uring_prep_writev(sqe, index, &iov[0], 1, 0);
+	sqe->flags |= IOSQE_FIXED_FILE;
+	sqe->user_data = 1;
+
+	ret = io_uring_submit(ring);
+	if (ret != 1) {
+		fprintf(stderr, "%s: got %d, wanted 1\n", __FUNCTION__, ret);
+		return 1;
+	}
+
+	ret = io_uring_wait_cqe(ring, &cqe);
+	if (ret < 0) {
+		fprintf(stderr, "%s: io_uring_wait_cqe=%d\n", __FUNCTION__, ret);
+		return 1;
+	}
+	if (cqe->res != 4096) {
+		fprintf(stderr, "%s: write cqe->res=%d\n", __FUNCTION__, cqe->res);
+		return 1;
+	}
+	io_uring_cqe_seen(ring, cqe);
+
+	sqe = io_uring_get_sqe(ring);
+	if (!sqe) {
+		fprintf(stderr, "%s: failed to get sqe\n", __FUNCTION__);
+		return 1;
+	}
+	io_uring_prep_readv(sqe, index, &iov[1], 1, 0);
+	sqe->flags |= IOSQE_FIXED_FILE;
+	sqe->user_data = 2;
+
+	ret = io_uring_submit(ring);
+	if (ret != 1) {
+		fprintf(stderr, "%s: got %d, wanted 1\n", __FUNCTION__, ret);
+		return 1;
+	}
+
+	ret = io_uring_wait_cqe(ring, &cqe);
+	if (ret < 0) {
+		fprintf(stderr, "%s: io_uring_wait_cqe=%d\n", __FUNCTION__, ret);
+		return 1;
+	}
+	if (cqe->res != 4096) {
+		fprintf(stderr, "%s: read cqe->res=%d\n", __FUNCTION__, cqe->res);
+		return 1;
+	}
+	io_uring_cqe_seen(ring, cqe);
+
+	if (memcmp(iov[1].iov_base, iov[0].iov_base, 4096)) {
+		fprintf(stderr, "%s: data mismatch\n", __FUNCTION__);
+		return 1;
+	}
+
+	free(iov[0].iov_base);
+	free(iov[1].iov_base);
+	return 0;
+}
+
+/*
+ * Register 8K of sparse files, update one at a random spot, then do some
+ * file IO to verify it works.
+ */
+static int test_huge(struct io_uring *ring)
+{
+	int *files;
+	int ret;
+
+	files = open_files(0, 8192, 0);
+	ret = io_uring_register_files(ring, files, 8192);
+	if (ret) {
+		/* huge sets not supported */
+		if (ret == -EMFILE) {
+			fprintf(stdout, "%s: No huge file set support, skipping\n", __FUNCTION__);
+			goto out;
+		}
+		fprintf(stderr, "%s: register ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+
+	files[7193] = open(".reg.7193", O_RDWR | O_CREAT, 0644);
+	if (files[7193] < 0) {
+		fprintf(stderr, "%s: open=%d\n", __FUNCTION__, errno);
+		goto err;
+	}
+
+	ret = io_uring_register_files_update(ring, 7193, &files[7193], 1);
+	if (ret != 1) {
+		fprintf(stderr, "%s: update ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+
+	if (test_fixed_read_write(ring, 7193))
+		goto err;
+
+	ret = io_uring_unregister_files(ring);
+	if (ret) {
+		fprintf(stderr, "%s: unregister ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+
+	if (files[7193] != -1) {
+		close(files[7193]);
+		unlink(".reg.7193");
+	}
+out:
+	free(files);
+	return 0;
+err:
+	if (files[7193] != -1) {
+		close(files[7193]);
+		unlink(".reg.7193");
+	}
+	free(files);
+	return 1;
+}
+
+static int test_skip(struct io_uring *ring)
+{
+	int *files;
+	int ret;
+
+	files = open_files(100, 0, 0);
+	ret = io_uring_register_files(ring, files, 100);
+	if (ret) {
+		fprintf(stderr, "%s: register ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+
+	files[90] = IORING_REGISTER_FILES_SKIP;
+	ret = io_uring_register_files_update(ring, 90, &files[90], 1);
+	if (ret != 1) {
+		if (ret == -EBADF) {
+			fprintf(stdout, "Skipping files not supported\n");
+			goto done;
+		}
+		fprintf(stderr, "%s: update ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+
+	/* verify can still use file index 90 */
+	if (test_fixed_read_write(ring, 90))
+		goto err;
+
+	ret = io_uring_unregister_files(ring);
+	if (ret) {
+		fprintf(stderr, "%s: unregister ret=%d\n", __FUNCTION__, ret);
+		goto err;
+	}
+
+done:
+	close_files(files, 100, 0);
+	return 0;
+err:
+	close_files(files, 100, 0);
+	return 1;
+}
+
+static int test_sparse_updates(void)
+{
+	struct io_uring ring;
+	int ret, i, *fds, newfd;
+
+	ret = io_uring_queue_init(8, &ring, 0);
+	if (ret) {
+		fprintf(stderr, "queue_init: %d\n", ret);
+		return ret;
+	}
+
+	fds = t_malloc(256 * sizeof(int));
+	for (i = 0; i < 256; i++)
+		fds[i] = -1;
+
+	ret = io_uring_register_files(&ring, fds, 256);
+	if (ret) {
+		fprintf(stderr, "file_register: %d\n", ret);
+		return ret;
+	}
+
+	newfd = 1;
+	for (i = 0; i < 256; i++) {
+		ret = io_uring_register_files_update(&ring, i, &newfd, 1);
+		if (ret != 1) {
+			fprintf(stderr, "file_update: %d\n", ret);
+			return ret;
+		}
+	}
+	io_uring_unregister_files(&ring);
+
+	for (i = 0; i < 256; i++)
+		fds[i] = 1;
+
+	ret = io_uring_register_files(&ring, fds, 256);
+	if (ret) {
+		fprintf(stderr, "file_register: %d\n", ret);
+		return ret;
+	}
+
+	newfd = -1;
+	for (i = 0; i < 256; i++) {
+		ret = io_uring_register_files_update(&ring, i, &newfd, 1);
+		if (ret != 1) {
+			fprintf(stderr, "file_update: %d\n", ret);
+			return ret;
+		}
+	}
+	io_uring_unregister_files(&ring);
+
+	io_uring_queue_exit(&ring);
+	return 0;
+}
+
+static int test_fixed_removal_ordering(void)
+{
+	char buffer[128];
+	struct io_uring ring;
+	struct io_uring_sqe *sqe;
+	struct io_uring_cqe *cqe;
+	struct __kernel_timespec ts;
+	int ret, fd, i, fds[2];
+
+	ret = io_uring_queue_init(8, &ring, 0);
+	if (ret < 0) {
+		fprintf(stderr, "failed to init io_uring: %s\n", strerror(-ret));
+		return ret;
+	}
+	if (pipe(fds)) {
+		perror("pipe");
+		return -1;
+	}
+	ret = io_uring_register_files(&ring, fds, 2);
+	if (ret) {
+		fprintf(stderr, "file_register: %d\n", ret);
+		return ret;
+	}
+	/* ring should have fds referenced, can close them */
+	close(fds[0]);
+	close(fds[1]);
+
+	sqe = io_uring_get_sqe(&ring);
+	if (!sqe) {
+		fprintf(stderr, "%s: get sqe failed\n", __FUNCTION__);
+		return 1;
+	}
+	/* outwait file recycling delay */
+	ts.tv_sec = 3;
+	ts.tv_nsec = 0;
+	io_uring_prep_timeout(sqe, &ts, 0, 0);
+	sqe->flags |= IOSQE_IO_LINK | IOSQE_IO_HARDLINK;
+	sqe->user_data = 1;
+
+	sqe = io_uring_get_sqe(&ring);
+	if (!sqe) {
+		printf("get sqe failed\n");
+		return -1;
+	}
+	io_uring_prep_write(sqe, 1, buffer, sizeof(buffer), 0);
+	sqe->flags |= IOSQE_FIXED_FILE;
+	sqe->user_data = 2;
+
+	ret = io_uring_submit(&ring);
+	if (ret != 2) {
+		fprintf(stderr, "%s: got %d, wanted 2\n", __FUNCTION__, ret);
+		return -1;
+	}
+
+	/* remove unused pipe end */
+	fd = -1;
+	ret = io_uring_register_files_update(&ring, 0, &fd, 1);
+	if (ret != 1) {
+		fprintf(stderr, "update off=0 failed\n");
+		return -1;
+	}
+
+	/* remove used pipe end */
+	fd = -1;
+	ret = io_uring_register_files_update(&ring, 1, &fd, 1);
+	if (ret != 1) {
+		fprintf(stderr, "update off=1 failed\n");
+		return -1;
+	}
+
+	for (i = 0; i < 2; ++i) {
+		ret = io_uring_wait_cqe(&ring, &cqe);
+		if (ret < 0) {
+			fprintf(stderr, "%s: io_uring_wait_cqe=%d\n", __FUNCTION__, ret);
+			return 1;
+		}
+		io_uring_cqe_seen(&ring, cqe);
+	}
+
+	io_uring_queue_exit(&ring);
+	return 0;
+}
+
+
+
+int main(int argc, char *argv[])
+{
+	struct io_uring ring;
+	int ret;
+
+	if (argc > 1)
+		return 0;
+
+	ret = io_uring_queue_init(8, &ring, 0);
+	if (ret) {
+		printf("ring setup failed\n");
+		return 1;
+	}
+
+	ret = test_basic(&ring, 0);
+	if (ret) {
+		printf("test_basic failed\n");
+		return ret;
+	}
+
+	ret = test_basic(&ring, 1);
+	if (ret) {
+		printf("test_basic failed\n");
+		return ret;
+	}
+
+	ret = test_basic_many(&ring);
+	if (ret) {
+		printf("test_basic_many failed\n");
+		return ret;
+	}
+
+	ret = test_sparse(&ring);
+	if (ret) {
+		printf("test_sparse failed\n");
+		return ret;
+	}
+
+	if (no_update)
+		return 0;
+
+	ret = test_additions(&ring);
+	if (ret) {
+		printf("test_additions failed\n");
+		return ret;
+	}
+
+	ret = test_removals(&ring);
+	if (ret) {
+		printf("test_removals failed\n");
+		return ret;
+	}
+
+	ret = test_replace(&ring);
+	if (ret) {
+		printf("test_replace failed\n");
+		return ret;
+	}
+
+	ret = test_replace_all(&ring);
+	if (ret) {
+		printf("test_replace_all failed\n");
+		return ret;
+	}
+
+	ret = test_grow(&ring);
+	if (ret) {
+		printf("test_grow failed\n");
+		return ret;
+	}
+
+	ret = test_shrink(&ring);
+	if (ret) {
+		printf("test_shrink failed\n");
+		return ret;
+	}
+
+	ret = test_zero(&ring);
+	if (ret) {
+		printf("test_zero failed\n");
+		return ret;
+	}
+
+	ret = test_huge(&ring);
+	if (ret) {
+		printf("test_huge failed\n");
+		return ret;
+	}
+
+	ret = test_skip(&ring);
+	if (ret) {
+		printf("test_skip failed\n");
+		return 1;
+	}
+
+	ret = test_sparse_updates();
+	if (ret) {
+		printf("test_sparse_updates failed\n");
+		return ret;
+	}
+
+	ret = test_fixed_removal_ordering();
+	if (ret) {
+		printf("test_fixed_removal_ordering failed\n");
+		return 1;
+	}
+
+	return 0;
+}
diff --git a/test/file-update.c b/test/file-update.c
new file mode 100644
index 0000000..38059d4
--- /dev/null
+++ b/test/file-update.c
@@ -0,0 +1,172 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: run various file registration tests
+ *
+ */
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+
+#include "helpers.h"
+#include "liburing.h"
+
+static void close_files(int *files, int nr_files, int add)
+{
+	char fname[32];
+	int i;
+
+	for (i = 0; i < nr_files; i++) {
+		if (files)
+			close(files[i]);
+		if (!add)
+			sprintf(fname, ".reg.%d", i);
+		else
+			sprintf(fname, ".add.%d", i + add);
+		unlink(fname);
+	}
+	if (files)
+		free(files);
+}
+
+static int *open_files(int nr_files, int extra, int add)
+{
+	char fname[32];
+	int *files;
+	int i;
+
+	files = t_calloc(nr_files + extra, sizeof(int));
+
+	for (i = 0; i < nr_files; i++) {
+		if (!add)
+			sprintf(fname, ".reg.%d", i);
+		else
+			sprintf(fname, ".add.%d", i + add);
+		files[i] = open(fname, O_RDWR | O_CREAT, 0644);
+		if (files[i] < 0) {
+			perror("open");
+			free(files);
+			files = NULL;
+			break;
+		}
+	}
+	if (extra) {
+		for (i = nr_files; i < nr_files + extra; i++)
+			files[i] = -1;
+	}
+
+	return files;
+}
+
+static int test_update_multiring(struct io_uring *r1, struct io_uring *r2,
+				 struct io_uring *r3, int do_unreg)
+{
+	int *fds, *newfds;
+
+	fds = open_files(10, 0, 0);
+	newfds = open_files(10, 0, 1);
+
+	if (io_uring_register_files(r1, fds, 10) ||
+	    io_uring_register_files(r2, fds, 10) ||
+	    io_uring_register_files(r3, fds, 10)) {
+		fprintf(stderr, "%s: register files failed\n", __FUNCTION__);
+		goto err;
+	}
+
+	if (io_uring_register_files_update(r1, 0, newfds, 10) != 10 ||
+	    io_uring_register_files_update(r2, 0, newfds, 10) != 10 ||
+	    io_uring_register_files_update(r3, 0, newfds, 10) != 10) {
+		fprintf(stderr, "%s: update files failed\n", __FUNCTION__);
+		goto err;
+	}
+
+	if (!do_unreg)
+		goto done;
+
+	if (io_uring_unregister_files(r1) ||
+	    io_uring_unregister_files(r2) ||
+	    io_uring_unregister_files(r3)) {
+		fprintf(stderr, "%s: unregister files failed\n", __FUNCTION__);
+		goto err;
+	}
+
+done:
+	close_files(fds, 10, 0);
+	close_files(newfds, 10, 1);
+	return 0;
+err:
+	close_files(fds, 10, 0);
+	close_files(newfds, 10, 1);
+	return 1;
+}
+
+static int test_sqe_update(struct io_uring *ring)
+{
+	struct io_uring_sqe *sqe;
+	struct io_uring_cqe *cqe;
+	int *fds, i, ret;
+
+	fds = t_malloc(sizeof(int) * 10);
+	for (i = 0; i < 10; i++)
+		fds[i] = -1;
+
+	sqe = io_uring_get_sqe(ring);
+	io_uring_prep_files_update(sqe, fds, 10, 0);
+	ret = io_uring_submit(ring);
+	if (ret != 1) {
+		fprintf(stderr, "submit: %d\n", ret);
+		return 1;
+	}
+
+	ret = io_uring_wait_cqe(ring, &cqe);
+	if (ret) {
+		fprintf(stderr, "wait: %d\n", ret);
+		return 1;
+	}
+
+	ret = cqe->res;
+	io_uring_cqe_seen(ring, cqe);
+	if (ret == -EINVAL) {
+		fprintf(stdout, "IORING_OP_FILES_UPDATE not supported, skipping\n");
+		return 0;
+	}
+	return ret != 10;
+}
+
+int main(int argc, char *argv[])
+{
+	struct io_uring r1, r2, r3;
+	int ret;
+
+	if (argc > 1)
+		return 0;
+
+	if (io_uring_queue_init(8, &r1, 0) ||
+	    io_uring_queue_init(8, &r2, 0) ||
+	    io_uring_queue_init(8, &r3, 0)) {
+		fprintf(stderr, "ring setup failed\n");
+		return 1;
+	}
+
+	ret = test_update_multiring(&r1, &r2, &r3, 1);
+	if (ret) {
+		fprintf(stderr, "test_update_multiring w/unreg\n");
+		return ret;
+	}
+
+	ret = test_update_multiring(&r1, &r2, &r3, 0);
+	if (ret) {
+		fprintf(stderr, "test_update_multiring wo/unreg\n");
+		return ret;
+	}
+
+	ret = test_sqe_update(&r1);
+	if (ret) {
+		fprintf(stderr, "test_sqe_update failed\n");
+		return ret;
+	}
+
+	return 0;
+}
diff --git a/test/files-exit-hang-poll.c b/test/files-exit-hang-poll.c
new file mode 100644
index 0000000..c3f7fb7
--- /dev/null
+++ b/test/files-exit-hang-poll.c
@@ -0,0 +1,128 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Based on a test case from Josef Grieb - test that we can exit without
+ * hanging if we have the task file table pinned by a request that is linked
+ * to another request that doesn't finish.
+ */
+#include <errno.h>
+#include <fcntl.h>
+#include <netinet/in.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#include <poll.h>
+#include "liburing.h"
+
+#define BACKLOG 512
+
+#define PORT 9100
+
+static struct io_uring ring;
+
+static void add_poll(struct io_uring *ring, int fd)
+{
+	struct io_uring_sqe *sqe;
+
+	sqe = io_uring_get_sqe(ring);
+	io_uring_prep_poll_add(sqe, fd, POLLIN);
+	sqe->flags |= IOSQE_IO_LINK;
+}
+
+static void add_accept(struct io_uring *ring, int fd)
+{
+	struct io_uring_sqe *sqe;
+
+	sqe = io_uring_get_sqe(ring);
+	io_uring_prep_accept(sqe, fd, 0, 0, SOCK_NONBLOCK | SOCK_CLOEXEC);
+}
+
+static int setup_io_uring(void)
+{
+	int ret;
+
+	ret = io_uring_queue_init(16, &ring, 0);
+	if (ret) {
+		fprintf(stderr, "Unable to setup io_uring: %s\n", strerror(-ret));
+		return 1;
+	}
+
+	return 0;
+}
+
+static void alarm_sig(int sig)
+{
+	exit(0);
+}
+
+int main(int argc, char *argv[])
+{
+	struct sockaddr_in serv_addr;
+	struct io_uring_cqe *cqe;
+	int ret, sock_listen_fd;
+	const int val = 1;
+	int i;
+
+	if (argc > 1)
+		return 0;
+
+	sock_listen_fd = socket(AF_INET, SOCK_STREAM | SOCK_NONBLOCK, 0);
+	if (sock_listen_fd < 0) {
+		perror("socket");
+		return 1;
+	}
+
+	setsockopt(sock_listen_fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
+
+	memset(&serv_addr, 0, sizeof(serv_addr));
+	serv_addr.sin_family = AF_INET;
+	serv_addr.sin_addr.s_addr = INADDR_ANY;
+
+	for (i = 0; i < 100; i++) {
+		serv_addr.sin_port = htons(PORT + i);
+
+		ret = bind(sock_listen_fd, (struct sockaddr *)&serv_addr, sizeof(serv_addr));
+		if (!ret)
+			break;
+		if (errno != EADDRINUSE) {
+			fprintf(stderr, "bind: %s\n", strerror(errno));
+			return 1;
+		}
+		if (i == 99) {
+			printf("Gave up on finding a port, skipping\n");
+			goto out;
+		}
+	}
+
+	if (listen(sock_listen_fd, BACKLOG) < 0) {
+		perror("Error listening on socket\n");
+		return 1;
+	}
+
+	if (setup_io_uring())
+		return 1;
+
+	add_poll(&ring, sock_listen_fd);
+	add_accept(&ring, sock_listen_fd);
+
+	ret = io_uring_submit(&ring);
+	if (ret != 2) {
+		fprintf(stderr, "submit=%d\n", ret);
+		return 1;
+	}
+
+	signal(SIGALRM, alarm_sig);
+	alarm(1);
+
+	ret = io_uring_wait_cqe(&ring, &cqe);
+	if (ret) {
+		fprintf(stderr, "wait_cqe=%d\n", ret);
+		return 1;
+	}
+
+out:
+	io_uring_queue_exit(&ring);
+	return 0;
+}
diff --git a/test/files-exit-hang-timeout.c b/test/files-exit-hang-timeout.c
new file mode 100644
index 0000000..09efc4f
--- /dev/null
+++ b/test/files-exit-hang-timeout.c
@@ -0,0 +1,134 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Based on a test case from Josef Grieb - test that we can exit without
+ * hanging if we have the task file table pinned by a request that is linked
+ * to another request that doesn't finish.
+ */
+#include <errno.h>
+#include <fcntl.h>
+#include <netinet/in.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#include <poll.h>
+#include "liburing.h"
+
+#define BACKLOG 512
+
+#define PORT 9100
+
+struct io_uring ring;
+
+struct __kernel_timespec ts = {
+	.tv_sec		= 300,
+	.tv_nsec	= 0,
+};
+
+static void add_timeout(struct io_uring *ring, int fd)
+{
+	struct io_uring_sqe *sqe;
+
+	sqe = io_uring_get_sqe(ring);
+	io_uring_prep_timeout(sqe, &ts, 100, 0);
+	sqe->flags |= IOSQE_IO_LINK;
+}
+
+static void add_accept(struct io_uring *ring, int fd)
+{
+	struct io_uring_sqe *sqe;
+
+	sqe = io_uring_get_sqe(ring);
+	io_uring_prep_accept(sqe, fd, 0, 0, SOCK_NONBLOCK | SOCK_CLOEXEC);
+	sqe->flags |= IOSQE_IO_LINK;
+}
+
+static int setup_io_uring(void)
+{
+	int ret;
+       
+	ret = io_uring_queue_init(16, &ring, 0);
+	if (ret) {
+		fprintf(stderr, "Unable to setup io_uring: %s\n", strerror(-ret));
+		return 1;
+	}
+
+	return 0;
+}
+
+static void alarm_sig(int sig)
+{
+	exit(0);
+}
+
+int main(int argc, char *argv[])
+{
+	struct sockaddr_in serv_addr;
+	struct io_uring_cqe *cqe;
+	int ret, sock_listen_fd;
+	const int val = 1;
+	int i;
+
+	if (argc > 1)
+		return 0;
+
+	sock_listen_fd = socket(AF_INET, SOCK_STREAM | SOCK_NONBLOCK, 0);
+	if (sock_listen_fd < 0) {
+		perror("socket");
+		return 1;
+	}
+
+	setsockopt(sock_listen_fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
+
+	memset(&serv_addr, 0, sizeof(serv_addr));
+	serv_addr.sin_family = AF_INET;
+	serv_addr.sin_addr.s_addr = INADDR_ANY;
+
+	for (i = 0; i < 100; i++) {
+		serv_addr.sin_port = htons(PORT + i);
+
+		ret = bind(sock_listen_fd, (struct sockaddr *)&serv_addr, sizeof(serv_addr));
+		if (!ret)
+			break;
+		if (errno != EADDRINUSE) {
+			fprintf(stderr, "bind: %s\n", strerror(errno));
+			return 1;
+		}
+		if (i == 99) {
+			printf("Gave up on finding a port, skipping\n");
+			goto out;
+		}
+	}
+
+	if (listen(sock_listen_fd, BACKLOG) < 0) {
+		perror("Error listening on socket\n");
+		return 1;
+	}
+
+	if (setup_io_uring())
+		return 1;
+
+	add_timeout(&ring, sock_listen_fd);
+	add_accept(&ring, sock_listen_fd);
+
+	ret = io_uring_submit(&ring);
+	if (ret != 2) {
+		fprintf(stderr, "submit=%d\n", ret);
+		return 1;
+	}
+
+	signal(SIGALRM, alarm_sig);
+	alarm(1);
+
+	ret = io_uring_wait_cqe(&ring, &cqe);
+	if (ret) {
+		fprintf(stderr, "wait_cqe=%d\n", ret);
+		return 1;
+	}
+
+out:
+	io_uring_queue_exit(&ring);
+	return 0;
+}
diff --git a/test/fixed-link.c b/test/fixed-link.c
new file mode 100644
index 0000000..60d96ec
--- /dev/null
+++ b/test/fixed-link.c
@@ -0,0 +1,90 @@
+/* SPDX-License-Identifier: MIT */
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <sys/types.h>
+
+#include "helpers.h"
+#include "liburing.h"
+
+#define IOVECS_LEN 2
+
+int main(int argc, char *argv[])
+{
+	struct iovec iovecs[IOVECS_LEN];
+	struct io_uring ring;
+	int i, fd, ret;
+
+	if (argc > 1)
+		return 0;
+
+	fd = open("/dev/zero", O_RDONLY);
+	if (fd < 0) {
+		fprintf(stderr, "Failed to open /dev/zero\n");
+		return 1;
+	}
+
+	if (io_uring_queue_init(32, &ring, 0) < 0) {
+		fprintf(stderr, "Faild to init io_uring\n");
+		close(fd);
+		return 1;
+	}
+
+	for (i = 0; i < IOVECS_LEN; ++i) {
+		iovecs[i].iov_base = t_malloc(64);
+		iovecs[i].iov_len = 64;
+	};
+
+	ret = io_uring_register_buffers(&ring, iovecs, IOVECS_LEN);
+	if (ret) {
+		fprintf(stderr, "Failed to register buffers\n");
+		return 1;
+	}
+
+	for (i = 0; i < IOVECS_LEN; ++i) {
+		struct io_uring_sqe *sqe = io_uring_get_sqe(&ring);
+		const char *str = "#include <errno.h>";
+
+		iovecs[i].iov_len = strlen(str);
+		io_uring_prep_read_fixed(sqe, fd, iovecs[i].iov_base, strlen(str), 0, i);
+		if (i == 0)
+			io_uring_sqe_set_flags(sqe, IOSQE_IO_LINK);
+		io_uring_sqe_set_data(sqe, (void *)str);
+	}
+
+	ret = io_uring_submit_and_wait(&ring, IOVECS_LEN);
+	if (ret < 0) {
+		fprintf(stderr, "Failed to submit IO\n");
+		return 1;
+	} else if (ret < 2) {
+		fprintf(stderr, "Submitted %d, wanted %d\n", ret, IOVECS_LEN);
+		return 1;
+	}
+
+	for (i = 0; i < IOVECS_LEN; i++) {
+		struct io_uring_cqe *cqe;
+
+		ret = io_uring_wait_cqe(&ring, &cqe);
+		if (ret) {
+			fprintf(stderr, "wait_cqe=%d\n", ret);
+			return 1;
+		}
+		if (cqe->res != iovecs[i].iov_len) {
+			fprintf(stderr, "read: wanted %ld, got %d\n",
+					(long) iovecs[i].iov_len, cqe->res);
+			return 1;
+		}
+		io_uring_cqe_seen(&ring, cqe);
+	}
+
+	close(fd);
+	io_uring_queue_exit(&ring);
+
+	for (i = 0; i < IOVECS_LEN; ++i)
+		free(iovecs[i].iov_base);
+
+	return 0;
+}
diff --git a/test/fsync.c b/test/fsync.c
new file mode 100644
index 0000000..7e93ecc
--- /dev/null
+++ b/test/fsync.c
@@ -0,0 +1,219 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: test io_uring fsync handling
+ *
+ */
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+
+#include "helpers.h"
+#include "liburing.h"
+
+static int test_single_fsync(struct io_uring *ring)
+{
+	struct io_uring_cqe *cqe;
+	struct io_uring_sqe *sqe;
+	char buf[32];
+	int fd, ret;
+
+	sprintf(buf, "./XXXXXX");
+	fd = mkstemp(buf);
+	if (fd < 0) {
+		perror("open");
+		return 1;
+	}
+
+	sqe = io_uring_get_sqe(ring);
+	if (!sqe) {
+		fprintf(stderr, "get sqe failed\n");
+		goto err;
+	}
+
+	io_uring_prep_fsync(sqe, fd, 0);
+
+	ret = io_uring_submit(ring);
+	if (ret <= 0) {
+		fprintf(stderr, "sqe submit failed: %d\n", ret);
+		goto err;
+	}
+
+	ret = io_uring_wait_cqe(ring, &cqe);
+	if (ret < 0) {
+		fprintf(stderr, "wait completion %d\n", ret);
+		goto err;
+	}
+
+	io_uring_cqe_seen(ring, cqe);
+	unlink(buf);
+	return 0;
+err:
+	unlink(buf);
+	return 1;
+}
+
+static int test_barrier_fsync(struct io_uring *ring)
+{
+	struct io_uring_cqe *cqe;
+	struct io_uring_sqe *sqe;
+	struct iovec iovecs[4];
+	int i, fd, ret;
+	off_t off;
+
+	fd = open("testfile", O_WRONLY | O_CREAT, 0644);
+	if (fd < 0) {
+		perror("open");
+		return 1;
+	}
+
+	for (i = 0; i < 4; i++) {
+		iovecs[i].iov_base = t_malloc(4096);
+		iovecs[i].iov_len = 4096;
+	}
+
+	off = 0;
+	for (i = 0; i < 4; i++) {
+		sqe = io_uring_get_sqe(ring);
+		if (!sqe) {
+			fprintf(stderr, "get sqe failed\n");
+			goto err;
+		}
+
+		io_uring_prep_writev(sqe, fd, &iovecs[i], 1, off);
+		sqe->user_data = 0;
+		off += 4096;
+	}
+
+	sqe = io_uring_get_sqe(ring);
+	if (!sqe) {
+		fprintf(stderr, "get sqe failed\n");
+		goto err;
+	}
+
+	io_uring_prep_fsync(sqe, fd, IORING_FSYNC_DATASYNC);
+	sqe->user_data = 1;
+	io_uring_sqe_set_flags(sqe, IOSQE_IO_DRAIN);
+
+	ret = io_uring_submit(ring);
+	if (ret < 0) {
+		fprintf(stderr, "sqe submit failed: %d\n", ret);
+		goto err;
+	} else if (ret < 5) {
+		fprintf(stderr, "Submitted only %d\n", ret);
+		goto err;
+	}
+
+	for (i = 0; i < 5; i++) {
+		ret = io_uring_wait_cqe(ring, &cqe);
+		if (ret < 0) {
+			fprintf(stderr, "wait completion %d\n", ret);
+			goto err;
+		}
+		/* kernel doesn't support IOSQE_IO_DRAIN */
+		if (cqe->res == -EINVAL)
+			break;
+		if (i <= 3) {
+			if (cqe->user_data) {
+				fprintf(stderr, "Got fsync early?\n");
+				goto err;
+			}
+		} else {
+			if (!cqe->user_data) {
+				fprintf(stderr, "Got write late?\n");
+				goto err;
+			}
+		}
+		io_uring_cqe_seen(ring, cqe);
+	}
+
+	unlink("testfile");
+	return 0;
+err:
+	unlink("testfile");
+	return 1;
+}
+
+#define FILE_SIZE 1024
+
+static int test_sync_file_range(struct io_uring *ring)
+{
+	int ret, fd, save_errno;
+	struct io_uring_sqe *sqe;
+	struct io_uring_cqe *cqe;
+
+	t_create_file(".sync_file_range", FILE_SIZE);
+
+	fd = open(".sync_file_range", O_RDWR);
+	save_errno = errno;
+	unlink(".sync_file_range");
+	errno = save_errno;
+	if (fd < 0) {
+		perror("file open");
+		return 1;
+	}
+
+	sqe = io_uring_get_sqe(ring);
+	if (!sqe) {
+		fprintf(stderr, "sqe get failed\n");
+		return 1;
+	}
+	io_uring_prep_sync_file_range(sqe, fd, 0, 0, 0);
+	sqe->user_data = 1;
+
+	ret = io_uring_submit(ring);
+	if (ret != 1) {
+		fprintf(stderr, "submit failed: %d\n", ret);
+		return 1;
+	}
+	ret = io_uring_wait_cqe(ring, &cqe);
+	if (ret) {
+		fprintf(stderr, "wait_cqe failed: %d\n", ret);
+		return 1;
+	}
+	if (cqe->res) {
+		fprintf(stderr, "sfr failed: %d\n", cqe->res);
+		return 1;
+	}
+
+	io_uring_cqe_seen(ring, cqe);
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	struct io_uring ring;
+	int ret;
+
+	if (argc > 1)
+		return 0;
+
+	ret = io_uring_queue_init(8, &ring, 0);
+	if (ret) {
+		fprintf(stderr, "ring setup failed\n");
+		return 1;
+
+	}
+
+	ret = test_single_fsync(&ring);
+	if (ret) {
+		fprintf(stderr, "test_single_fsync failed\n");
+		return ret;
+	}
+
+	ret = test_barrier_fsync(&ring);
+	if (ret) {
+		fprintf(stderr, "test_barrier_fsync failed\n");
+		return ret;
+	}
+
+	ret = test_sync_file_range(&ring);
+	if (ret) {
+		fprintf(stderr, "test_sync_file_range failed\n");
+		return ret;
+	}
+
+	return 0;
+}
diff --git a/test/hardlink.c b/test/hardlink.c
new file mode 100644
index 0000000..1c73424
--- /dev/null
+++ b/test/hardlink.c
@@ -0,0 +1,133 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: test io_uring linkat handling
+ */
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "liburing.h"
+
+
+static int do_linkat(struct io_uring *ring, const char *oldname, const char *newname)
+{
+	int ret;
+	struct io_uring_sqe *sqe;
+	struct io_uring_cqe *cqe;
+
+	sqe = io_uring_get_sqe(ring);
+	if (!sqe) {
+		fprintf(stderr, "sqe get failed\n");
+		goto err;
+	}
+	io_uring_prep_linkat(sqe, AT_FDCWD, oldname, AT_FDCWD, newname, 0);
+
+	ret = io_uring_submit(ring);
+	if (ret != 1) {
+		fprintf(stderr, "submit failed: %d\n", ret);
+		goto err;
+	}
+
+	ret = io_uring_wait_cqes(ring, &cqe, 1, 0, 0);
+	if (ret) {
+		fprintf(stderr, "wait_cqe failed: %d\n", ret);
+		goto err;
+	}
+	ret = cqe->res;
+	io_uring_cqe_seen(ring, cqe);
+	return ret;
+err:
+	return 1;
+}
+
+int files_linked_ok(const char* fn1, const char *fn2)
+{
+	struct stat s1, s2;
+
+	if (stat(fn1, &s1)) {
+		fprintf(stderr, "stat(%s): %s\n", fn1, strerror(errno));
+		return 0;
+	}
+	if (stat(fn2, &s2)) {
+		fprintf(stderr, "stat(%s): %s\n", fn2, strerror(errno));
+		return 0;
+	}
+	if (s1.st_dev != s2.st_dev || s1.st_ino != s2.st_ino) {
+		fprintf(stderr, "linked files have different device / inode numbers\n");
+		return 0;
+	}
+	if (s1.st_nlink != 2 || s2.st_nlink != 2) {
+		fprintf(stderr, "linked files have unexpected links count\n");
+		return 0;
+	}
+	return 1;
+}
+
+int main(int argc, char *argv[])
+{
+	static const char target[] = "io_uring-linkat-test-target";
+	static const char linkname[] = "io_uring-linkat-test-link";
+	int ret;
+	struct io_uring ring;
+
+	ret = io_uring_queue_init(8, &ring, 0);
+	if (ret) {
+		fprintf(stderr, "queue init failed: %d\n", ret);
+		return ret;
+	}
+
+	ret = open(target, O_CREAT | O_RDWR | O_EXCL, 0600);
+	if (ret < 0) {
+		perror("open");
+		goto err;
+	}
+	if (write(ret, "linktest", 8) != 8) {
+		close(ret);
+		goto err1;
+	}
+	close(ret);
+
+	ret = do_linkat(&ring, target, linkname);
+	if (ret < 0) {
+		if (ret == -EBADF || ret == -EINVAL) {
+			fprintf(stdout, "linkat not supported, skipping\n");
+			goto out;
+		}
+		fprintf(stderr, "linkat: %s\n", strerror(-ret));
+		goto err1;
+	} else if (ret) {
+		goto err1;
+	}
+
+	if (!files_linked_ok(linkname, target))
+		goto err2;
+
+	ret = do_linkat(&ring, target, linkname);
+	if (ret != -EEXIST) {
+		fprintf(stderr, "test_linkat linkname already exists failed: %d\n", ret);
+		goto err2;
+	}
+
+	ret = do_linkat(&ring, target, "surely/this/does/not/exist");
+	if (ret != -ENOENT) {
+		fprintf(stderr, "test_linkat no parent failed: %d\n", ret);
+		goto err2;
+	}
+
+out:
+	unlinkat(AT_FDCWD, linkname, 0);
+	unlinkat(AT_FDCWD, target, 0);
+	io_uring_queue_exit(&ring);
+	return 0;
+err2:
+	unlinkat(AT_FDCWD, linkname, 0);
+err1:
+	unlinkat(AT_FDCWD, target, 0);
+err:
+	io_uring_queue_exit(&ring);
+	return 1;
+}
+
diff --git a/test/helpers.c b/test/helpers.c
new file mode 100644
index 0000000..930d82a
--- /dev/null
+++ b/test/helpers.c
@@ -0,0 +1,116 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: Helpers for tests.
+ */
+#include <stdlib.h>
+#include <assert.h>
+#include <string.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/types.h>
+
+#include "helpers.h"
+#include "liburing.h"
+
+/*
+ * Helper for allocating memory in tests.
+ */
+void *t_malloc(size_t size)
+{
+	void *ret;
+	ret = malloc(size);
+	assert(ret);
+	return ret;
+}
+
+/*
+ * Helper for allocating size bytes aligned on a boundary.
+ */
+void t_posix_memalign(void **memptr, size_t alignment, size_t size)
+{
+	int ret;
+	ret = posix_memalign(memptr, alignment, size);
+	assert(!ret);
+}
+
+/*
+ * Helper for allocating space for an array of nmemb elements
+ * with size bytes for each element.
+ */
+void *t_calloc(size_t nmemb, size_t size)
+{
+	void *ret;
+	ret = calloc(nmemb, size);
+	assert(ret);
+	return ret;
+}
+
+/*
+ * Helper for creating file and write @size byte buf with 0xaa value in the file.
+ */
+void t_create_file(const char *file, size_t size)
+{
+	ssize_t ret;
+	char *buf;
+	int fd; 
+
+	buf = t_malloc(size);
+	memset(buf, 0xaa, size);
+
+	fd = open(file, O_WRONLY | O_CREAT, 0644);
+	assert(fd >= 0);
+
+	ret = write(fd, buf, size);
+	fsync(fd);
+	close(fd);
+	free(buf);
+	assert(ret == size);
+}
+
+/*
+ * Helper for creating @buf_num number of iovec
+ * with @buf_size bytes buffer of each iovec.
+ */
+struct iovec *t_create_buffers(size_t buf_num, size_t buf_size)
+{
+	struct iovec *vecs;
+	int i;
+
+	vecs = t_malloc(buf_num * sizeof(struct iovec));
+	for (i = 0; i < buf_num; i++) {
+		t_posix_memalign(&vecs[i].iov_base, buf_size, buf_size);
+		vecs[i].iov_len = buf_size; 
+	}
+	return vecs;
+}
+
+/*
+ * Helper for setting up an io_uring instance, skipping if the given user isn't
+ * allowed to.
+ */
+enum t_setup_ret t_create_ring_params(int depth, struct io_uring *ring,
+				      struct io_uring_params *p)
+{
+	int ret;
+
+	ret = io_uring_queue_init_params(depth, ring, p);
+	if (!ret)
+		return T_SETUP_OK;
+	if ((p->flags & IORING_SETUP_SQPOLL) && ret == -EPERM && geteuid()) {
+		fprintf(stdout, "SQPOLL skipped for regular user\n");
+		return T_SETUP_SKIP;
+	}
+
+	fprintf(stderr, "queue_init: %s\n", strerror(-ret));
+	return ret;
+}
+
+enum t_setup_ret t_create_ring(int depth, struct io_uring *ring,
+			       unsigned int flags)
+{
+	struct io_uring_params p = { };
+
+	p.flags = flags;
+	return t_create_ring_params(depth, ring, &p);
+}
diff --git a/test/helpers.h b/test/helpers.h
new file mode 100644
index 0000000..74fe162
--- /dev/null
+++ b/test/helpers.h
@@ -0,0 +1,61 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: Helpers for tests.
+ */
+#ifndef LIBURING_HELPERS_H
+#define LIBURING_HELPERS_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "liburing.h"
+
+enum t_setup_ret {
+	T_SETUP_OK	= 0,
+	T_SETUP_SKIP,
+};
+
+/*
+ * Helper for allocating memory in tests.
+ */
+void *t_malloc(size_t size);
+
+
+/*
+ * Helper for allocating size bytes aligned on a boundary.
+ */
+void t_posix_memalign(void **memptr, size_t alignment, size_t size);
+
+
+/*
+ * Helper for allocating space for an array of nmemb elements
+ * with size bytes for each element.
+ */
+void *t_calloc(size_t nmemb, size_t size);
+
+
+/*
+ * Helper for creating file and write @size byte buf with 0xaa value in the file.
+ */
+void t_create_file(const char *file, size_t size);
+
+/*
+ * Helper for creating @buf_num number of iovec
+ * with @buf_size bytes buffer of each iovec.
+ */
+struct iovec *t_create_buffers(size_t buf_num, size_t buf_size);
+
+/*
+ * Helper for setting up a ring and checking for user privs
+ */
+enum t_setup_ret t_create_ring_params(int depth, struct io_uring *ring,
+				      struct io_uring_params *p);
+enum t_setup_ret t_create_ring(int depth, struct io_uring *ring,
+			       unsigned int flags);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/test/io-cancel.c b/test/io-cancel.c
new file mode 100644
index 0000000..9a36dd9
--- /dev/null
+++ b/test/io-cancel.c
@@ -0,0 +1,531 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Description: Basic IO cancel test
+ */
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/wait.h>
+#include <sys/poll.h>
+
+#include "helpers.h"
+#include "liburing.h"
+
+#define FILE_SIZE	(128 * 1024)
+#define BS		4096
+#define BUFFERS		(FILE_SIZE / BS)
+
+static struct iovec *vecs;
+
+static unsigned long long utime_since(const struct timeval *s,
+				      const struct timeval *e)
+{
+	long long sec, usec;
+
+	sec = e->tv_sec - s->tv_sec;
+	usec = (e->tv_usec - s->tv_usec);
+	if (sec > 0 && usec < 0) {
+		sec--;
+		usec += 1000000;
+	}
+
+	sec *= 1000000;
+	return sec + usec;
+}
+
+static unsigned long long utime_since_now(struct timeval *tv)
+{
+	struct timeval end;
+
+	gettimeofday(&end, NULL);
+	return utime_since(tv, &end);
+}
+
+static int start_io(struct io_uring *ring, int fd, int do_write)
+{
+	struct io_uring_sqe *sqe;
+	int i, ret;
+
+	for (i = 0; i < BUFFERS; i++) {
+		off_t offset;
+
+		sqe = io_uring_get_sqe(ring);
+		if (!sqe) {
+			fprintf(stderr, "sqe get failed\n");
+			goto err;
+		}
+		offset = BS * (rand() % BUFFERS);
+		if (do_write) {
+			io_uring_prep_writev(sqe, fd, &vecs[i], 1, offset);
+		} else {
+			io_uring_prep_readv(sqe, fd, &vecs[i], 1, offset);
+		}
+		sqe->user_data = i + 1;
+	}
+
+	ret = io_uring_submit(ring);
+	if (ret != BUFFERS) {
+		fprintf(stderr, "submit got %d, wanted %d\n", ret, BUFFERS);
+		goto err;
+	}
+
+	return 0;
+err:
+	return 1;
+}
+
+static int wait_io(struct io_uring *ring, unsigned nr_io, int do_partial)
+{
+	struct io_uring_cqe *cqe;
+	int i, ret;
+
+	for (i = 0; i < nr_io; i++) {
+		ret = io_uring_wait_cqe(ring, &cqe);
+		if (ret) {
+			fprintf(stderr, "wait_cqe=%d\n", ret);
+			goto err;
+		}
+		if (do_partial && cqe->user_data) {
+			if (!(cqe->user_data & 1)) {
+				if (cqe->res != BS) {
+					fprintf(stderr, "IO %d wasn't cancelled but got error %d\n", (unsigned) cqe->user_data, cqe->res);
+					goto err;
+				}
+			}
+		}
+		io_uring_cqe_seen(ring, cqe);
+	}
+	return 0;
+err:
+	return 1;
+
+}
+
+static int do_io(struct io_uring *ring, int fd, int do_write)
+{
+	if (start_io(ring, fd, do_write))
+		return 1;
+	if (wait_io(ring, BUFFERS, 0))
+		return 1;
+	return 0;
+}
+
+static int start_cancel(struct io_uring *ring, int do_partial)
+{
+	struct io_uring_sqe *sqe;
+	int i, ret, submitted = 0;
+
+	for (i = 0; i < BUFFERS; i++) {
+		if (do_partial && (i & 1))
+			continue;
+		sqe = io_uring_get_sqe(ring);
+		if (!sqe) {
+			fprintf(stderr, "sqe get failed\n");
+			goto err;
+		}
+		io_uring_prep_cancel(sqe, (void *) (unsigned long) i + 1, 0);
+		sqe->user_data = 0;
+		submitted++;
+	}
+
+	ret = io_uring_submit(ring);
+	if (ret != submitted) {
+		fprintf(stderr, "submit got %d, wanted %d\n", ret, submitted);
+		goto err;
+	}
+	return 0;
+err:
+	return 1;
+}
+
+/*
+ * Test cancels. If 'do_partial' is set, then we only attempt to cancel half of
+ * the submitted IO. This is done to verify that cancelling one piece of IO doesn't
+ * impact others.
+ */
+static int test_io_cancel(const char *file, int do_write, int do_partial)
+{
+	struct io_uring ring;
+	struct timeval start_tv;
+	unsigned long usecs;
+	unsigned to_wait;
+	int fd, ret;
+
+	fd = open(file, O_RDWR | O_DIRECT);
+	if (fd < 0) {
+		perror("file open");
+		goto err;
+	}
+
+	ret = io_uring_queue_init(4 * BUFFERS, &ring, 0);
+	if (ret) {
+		fprintf(stderr, "ring create failed: %d\n", ret);
+		goto err;
+	}
+
+	if (do_io(&ring, fd, do_write))
+		goto err;
+	gettimeofday(&start_tv, NULL);
+	if (do_io(&ring, fd, do_write))
+		goto err;
+	usecs = utime_since_now(&start_tv);
+
+	if (start_io(&ring, fd, do_write))
+		goto err;
+	/* sleep for 1/3 of the total time, to allow some to start/complete */
+	usleep(usecs / 3);
+	if (start_cancel(&ring, do_partial))
+		goto err;
+	to_wait = BUFFERS;
+	if (do_partial)
+		to_wait += BUFFERS / 2;
+	else
+		to_wait += BUFFERS;
+	if (wait_io(&ring, to_wait, do_partial))
+		goto err;
+
+	io_uring_queue_exit(&ring);
+	close(fd);
+	return 0;
+err:
+	if (fd != -1)
+		close(fd);
+	return 1;
+}
+
+static int test_dont_cancel_another_ring(void)
+{
+	struct io_uring ring1, ring2;
+	struct io_uring_cqe *cqe;
+	struct io_uring_sqe *sqe;
+	char buffer[128];
+	int ret, fds[2];
+	struct __kernel_timespec ts = { .tv_sec = 0, .tv_nsec = 100000000, };
+
+	ret = io_uring_queue_init(8, &ring1, 0);
+	if (ret) {
+		fprintf(stderr, "ring create failed: %d\n", ret);
+		return 1;
+	}
+	ret = io_uring_queue_init(8, &ring2, 0);
+	if (ret) {
+		fprintf(stderr, "ring create failed: %d\n", ret);
+		return 1;
+	}
+	if (pipe(fds)) {
+		perror("pipe");
+		return 1;
+	}
+
+	sqe = io_uring_get_sqe(&ring1);
+	if (!sqe) {
+		fprintf(stderr, "%s: failed to get sqe\n", __FUNCTION__);
+		return 1;
+	}
+	io_uring_prep_read(sqe, fds[0], buffer, 10, 0);
+	sqe->flags |= IOSQE_ASYNC;
+	sqe->user_data = 1;
+
+	ret = io_uring_submit(&ring1);
+	if (ret != 1) {
+		fprintf(stderr, "%s: got %d, wanted 1\n", __FUNCTION__, ret);
+		return 1;
+	}
+
+	/* make sure it doesn't cancel requests of the other ctx */
+	sqe = io_uring_get_sqe(&ring2);
+	if (!sqe) {
+		fprintf(stderr, "%s: failed to get sqe\n", __FUNCTION__);
+		return 1;
+	}
+	io_uring_prep_cancel(sqe, (void *) (unsigned long)1, 0);
+	sqe->user_data = 2;
+
+	ret = io_uring_submit(&ring2);
+	if (ret != 1) {
+		fprintf(stderr, "%s: got %d, wanted 1\n", __FUNCTION__, ret);
+		return 1;
+	}
+
+	ret = io_uring_wait_cqe(&ring2, &cqe);
+	if (ret) {
+		fprintf(stderr, "wait_cqe=%d\n", ret);
+		return 1;
+	}
+	if (cqe->user_data != 2 || cqe->res != -ENOENT) {
+		fprintf(stderr, "error: cqe %i: res=%i, but expected -ENOENT\n",
+			(int)cqe->user_data, (int)cqe->res);
+		return 1;
+	}
+	io_uring_cqe_seen(&ring2, cqe);
+
+	ret = io_uring_wait_cqe_timeout(&ring1, &cqe, &ts);
+	if (ret != -ETIME) {
+		fprintf(stderr, "read got cancelled or wait failed\n");
+		return 1;
+	}
+	io_uring_cqe_seen(&ring1, cqe);
+
+	close(fds[0]);
+	close(fds[1]);
+	io_uring_queue_exit(&ring1);
+	io_uring_queue_exit(&ring2);
+	return 0;
+}
+
+static int test_cancel_req_across_fork(void)
+{
+	struct io_uring ring;
+	struct io_uring_cqe *cqe;
+	struct io_uring_sqe *sqe;
+	char buffer[128];
+	int ret, i, fds[2];
+	pid_t p;
+
+	ret = io_uring_queue_init(8, &ring, 0);
+	if (ret) {
+		fprintf(stderr, "ring create failed: %d\n", ret);
+		return 1;
+	}
+	if (pipe(fds)) {
+		perror("pipe");
+		return 1;
+	}
+	sqe = io_uring_get_sqe(&ring);
+	if (!sqe) {
+		fprintf(stderr, "%s: failed to get sqe\n", __FUNCTION__);
+		return 1;
+	}
+	io_uring_prep_read(sqe, fds[0], buffer, 10, 0);
+	sqe->flags |= IOSQE_ASYNC;
+	sqe->user_data = 1;
+
+	ret = io_uring_submit(&ring);
+	if (ret != 1) {
+		fprintf(stderr, "%s: got %d, wanted 1\n", __FUNCTION__, ret);
+		return 1;
+	}
+
+	p = fork();
+	if (p == -1) {
+		fprintf(stderr, "fork() failed\n");
+		return 1;
+	}
+
+	if (p == 0) {
+		sqe = io_uring_get_sqe(&ring);
+		if (!sqe) {
+			fprintf(stderr, "%s: failed to get sqe\n", __FUNCTION__);
+			return 1;
+		}
+		io_uring_prep_cancel(sqe, (void *) (unsigned long)1, 0);
+		sqe->user_data = 2;
+
+		ret = io_uring_submit(&ring);
+		if (ret != 1) {
+			fprintf(stderr, "%s: got %d, wanted 1\n", __FUNCTION__, ret);
+			return 1;
+		}
+
+		for (i = 0; i < 2; ++i) {
+			ret = io_uring_wait_cqe(&ring, &cqe);
+			if (ret) {
+				fprintf(stderr, "wait_cqe=%d\n", ret);
+				return 1;
+			}
+			if ((cqe->user_data == 1 && cqe->res != -EINTR) ||
+			    (cqe->user_data == 2 && cqe->res != -EALREADY)) {
+				fprintf(stderr, "%i %i\n", (int)cqe->user_data, cqe->res);
+				exit(1);
+			}
+
+			io_uring_cqe_seen(&ring, cqe);
+		}
+		exit(0);
+	} else {
+		int wstatus;
+
+		if (waitpid(p, &wstatus, 0) == (pid_t)-1) {
+			perror("waitpid()");
+			return 1;
+		}
+		if (!WIFEXITED(wstatus) || WEXITSTATUS(wstatus)) {
+			fprintf(stderr, "child failed %i\n", WEXITSTATUS(wstatus));
+			return 1;
+		}
+	}
+
+	close(fds[0]);
+	close(fds[1]);
+	io_uring_queue_exit(&ring);
+	return 0;
+}
+
+static int test_cancel_inflight_exit(void)
+{
+	struct __kernel_timespec ts = { .tv_sec = 1, .tv_nsec = 0, };
+	struct io_uring ring;
+	struct io_uring_cqe *cqe;
+	struct io_uring_sqe *sqe;
+	int ret, i;
+	pid_t p;
+
+	ret = io_uring_queue_init(8, &ring, 0);
+	if (ret) {
+		fprintf(stderr, "ring create failed: %d\n", ret);
+		return 1;
+	}
+	p = fork();
+	if (p == -1) {
+		fprintf(stderr, "fork() failed\n");
+		return 1;
+	}
+
+	if (p == 0) {
+		sqe = io_uring_get_sqe(&ring);
+		io_uring_prep_poll_add(sqe, ring.ring_fd, POLLIN);
+		sqe->user_data = 1;
+		sqe->flags |= IOSQE_IO_LINK;
+
+		sqe = io_uring_get_sqe(&ring);
+		io_uring_prep_timeout(sqe, &ts, 0, 0);
+		sqe->user_data = 2;
+
+		sqe = io_uring_get_sqe(&ring);
+		io_uring_prep_timeout(sqe, &ts, 0, 0);
+		sqe->user_data = 3;
+
+		ret = io_uring_submit(&ring);
+		if (ret != 3) {
+			fprintf(stderr, "io_uring_submit() failed %s, ret %i\n", __FUNCTION__, ret);
+			exit(1);
+		}
+		exit(0);
+	} else {
+		int wstatus;
+
+		if (waitpid(p, &wstatus, 0) == (pid_t)-1) {
+			perror("waitpid()");
+			return 1;
+		}
+		if (!WIFEXITED(wstatus) || WEXITSTATUS(wstatus)) {
+			fprintf(stderr, "child failed %i\n", WEXITSTATUS(wstatus));
+			return 1;
+		}
+	}
+
+	for (i = 0; i < 3; ++i) {
+		ret = io_uring_wait_cqe(&ring, &cqe);
+		if (ret) {
+			fprintf(stderr, "wait_cqe=%d\n", ret);
+			return 1;
+		}
+		if ((cqe->user_data == 1 && cqe->res != -ECANCELED) ||
+		    (cqe->user_data == 2 && cqe->res != -ECANCELED) ||
+		    (cqe->user_data == 3 && cqe->res != -ETIME)) {
+			fprintf(stderr, "%i %i\n", (int)cqe->user_data, cqe->res);
+			return 1;
+		}
+		io_uring_cqe_seen(&ring, cqe);
+	}
+
+	io_uring_queue_exit(&ring);
+	return 0;
+}
+
+static int test_sqpoll_cancel_iowq_requests(void)
+{
+	struct io_uring ring;
+	struct io_uring_sqe *sqe;
+	int ret, fds[2];
+	char buffer[16];
+
+	ret = io_uring_queue_init(8, &ring, IORING_SETUP_SQPOLL);
+	if (ret) {
+		fprintf(stderr, "ring create failed: %d\n", ret);
+		return 1;
+	}
+	if (pipe(fds)) {
+		perror("pipe");
+		return 1;
+	}
+	/* pin both pipe ends via io-wq */
+	sqe = io_uring_get_sqe(&ring);
+	io_uring_prep_read(sqe, fds[0], buffer, 10, 0);
+	sqe->flags |= IOSQE_ASYNC | IOSQE_IO_LINK;
+	sqe->user_data = 1;
+
+	sqe = io_uring_get_sqe(&ring);
+	io_uring_prep_write(sqe, fds[1], buffer, 10, 0);
+	sqe->flags |= IOSQE_ASYNC;
+	sqe->user_data = 2;
+	ret = io_uring_submit(&ring);
+	if (ret != 2) {
+		fprintf(stderr, "%s: got %d, wanted 1\n", __FUNCTION__, ret);
+		return 1;
+	}
+
+	/* wait for sqpoll to kick in and submit before exit */
+	sleep(1);
+	io_uring_queue_exit(&ring);
+
+	/* close the write end, so if ring is cancelled properly read() fails*/
+	close(fds[1]);
+	ret = read(fds[0], buffer, 10);
+	close(fds[0]);
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	int i, ret;
+
+	if (argc > 1)
+		return 0;
+
+	if (test_dont_cancel_another_ring()) {
+		fprintf(stderr, "test_dont_cancel_another_ring() failed\n");
+		return 1;
+	}
+
+	if (test_cancel_req_across_fork()) {
+		fprintf(stderr, "test_cancel_req_across_fork() failed\n");
+		return 1;
+	}
+
+	if (test_cancel_inflight_exit()) {
+		fprintf(stderr, "test_cancel_inflight_exit() failed\n");
+		return 1;
+	}
+
+	if (test_sqpoll_cancel_iowq_requests()) {
+		fprintf(stderr, "test_sqpoll_cancel_iowq_requests() failed\n");
+		return 1;
+	}
+
+	t_create_file(".basic-rw", FILE_SIZE);
+
+	vecs = t_create_buffers(BUFFERS, BS);
+
+	for (i = 0; i < 4; i++) {
+		int v1 = (i & 1) != 0;
+		int v2 = (i & 2) != 0;
+
+		ret = test_io_cancel(".basic-rw", v1, v2);
+		if (ret) {
+			fprintf(stderr, "test_io_cancel %d %d failed\n", v1, v2);
+			goto err;
+		}
+	}
+
+	unlink(".basic-rw");
+	return 0;
+err:
+	unlink(".basic-rw");
+	return 1;
+}
diff --git a/test/io_uring_enter.c b/test/io_uring_enter.c
new file mode 100644
index 0000000..a6bb8f5
--- /dev/null
+++ b/test/io_uring_enter.c
@@ -0,0 +1,293 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * io_uring_enter.c
+ *
+ * Description: Unit tests for the io_uring_enter system call.
+ *
+ * Copyright 2019, Red Hat, Inc.
+ * Author: Jeff Moyer <jmoyer@redhat.com>
+ */
+#include <stdio.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/sysinfo.h>
+#include <poll.h>
+#include <assert.h>
+#include <sys/uio.h>
+#include <sys/mman.h>
+#include <linux/mman.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <limits.h>
+#include <sys/time.h>
+
+#include "helpers.h"
+#include "liburing.h"
+#include "liburing/barrier.h"
+#include "../src/syscall.h"
+
+#define IORING_MAX_ENTRIES 4096
+
+int
+expect_failed_submit(struct io_uring *ring, int error)
+{
+	int ret;
+
+	ret = io_uring_submit(ring);
+	if (ret == 1) {
+		printf("expected failure, but io_uring_submit succeeded.\n");
+		return 1;
+	}
+
+	if (errno != error) {
+		printf("expected %d, got %d\n", error, errno);
+		return 1;
+	}
+
+	return 0;
+}
+
+int
+expect_fail(int fd, unsigned int to_submit, unsigned int min_complete,
+	    unsigned int flags, sigset_t *sig, int error)
+{
+	int ret;
+
+	ret = __sys_io_uring_enter(fd, to_submit, min_complete, flags, sig);
+	if (ret != -1) {
+		printf("expected %s, but call succeeded\n", strerror(error));
+		return 1;
+	}
+
+	if (errno != error) {
+		printf("expected %d, got %d\n", error, errno);
+		return 1;
+	}
+
+	return 0;
+}
+
+int
+try_io_uring_enter(int fd, unsigned int to_submit, unsigned int min_complete,
+		   unsigned int flags, sigset_t *sig, int expect, int error)
+{
+	int ret;
+
+	printf("io_uring_enter(%d, %u, %u, %u, %p)\n", fd, to_submit,
+	       min_complete, flags, sig);
+
+	if (expect == -1)
+		return expect_fail(fd, to_submit, min_complete,
+				   flags, sig, error);
+
+	ret = __sys_io_uring_enter(fd, to_submit, min_complete, flags, sig);
+	if (ret != expect) {
+		printf("Expected %d, got %d\n", expect, errno);
+		return 1;
+	}
+
+	return 0;
+}
+
+/*
+ * prep a read I/O.  index is treated like a block number.
+ */
+int
+setup_file(char *template, off_t len)
+{
+	int fd, ret;
+	char buf[4096];
+
+	fd = mkstemp(template);
+	if (fd < 0) {
+		perror("mkstemp");
+		exit(1);
+	}
+	ret = ftruncate(fd, len);
+	if (ret < 0) {
+		perror("ftruncate");
+		exit(1);
+	}
+
+	ret = read(fd, buf, 4096);
+	if (ret != 4096) {
+		printf("read returned %d, expected 4096\n", ret);
+		exit(1);
+	}
+
+	return fd;
+}
+
+void
+io_prep_read(struct io_uring_sqe *sqe, int fd, off_t offset, size_t len)
+{
+	struct iovec *iov;
+
+	iov = t_malloc(sizeof(*iov));
+	assert(iov);
+
+	iov->iov_base = t_malloc(len);
+	assert(iov->iov_base);
+	iov->iov_len = len;
+
+	io_uring_prep_readv(sqe, fd, iov, 1, offset);
+	io_uring_sqe_set_data(sqe, iov); // free on completion
+}
+
+void
+reap_events(struct io_uring *ring, unsigned nr)
+{
+	int ret;
+	unsigned left = nr;
+	struct io_uring_cqe *cqe;
+	struct iovec *iov;
+	struct timeval start, now, elapsed;
+
+	printf("Reaping %u I/Os\n", nr);
+	gettimeofday(&start, NULL);
+	while (left) {
+		ret = io_uring_wait_cqe(ring, &cqe);
+		if (ret < 0) {
+			printf("io_uring_wait_cqe returned %d\n", ret);
+			printf("expected success\n");
+			exit(1);
+		}
+		if (cqe->res != 4096)
+			printf("cqe->res: %d, expected 4096\n", cqe->res);
+		iov = io_uring_cqe_get_data(cqe);
+		free(iov->iov_base);
+		free(iov);
+		left--;
+		io_uring_cqe_seen(ring, cqe);
+
+		gettimeofday(&now, NULL);
+		timersub(&now, &start, &elapsed);
+		if (elapsed.tv_sec > 10) {
+			printf("Timed out waiting for I/Os to complete.\n");
+			printf("%u expected, %u completed\n", nr, left);
+			break;
+		}
+	}
+}
+
+void
+submit_io(struct io_uring *ring, unsigned nr)
+{
+	int fd, ret;
+	off_t file_len;
+	unsigned i;
+	static char template[32] = "/tmp/io_uring_enter-test.XXXXXX";
+	struct io_uring_sqe *sqe;
+
+	printf("Allocating %u sqes\n", nr);
+	file_len = nr * 4096;
+	fd = setup_file(template, file_len);
+	for (i = 0; i < nr; i++) {
+		/* allocate an sqe */
+		sqe = io_uring_get_sqe(ring);
+		/* fill it in */
+		io_prep_read(sqe, fd, i * 4096, 4096);
+	}
+
+	/* submit the I/Os */
+	printf("Submitting %u I/Os\n", nr);
+	ret = io_uring_submit(ring);
+	unlink(template);
+	if (ret < 0) {
+		perror("io_uring_enter");
+		exit(1);
+	}
+	printf("Done\n");
+}
+
+int
+main(int argc, char **argv)
+{
+	int ret;
+	unsigned int status = 0;
+	struct io_uring ring;
+	struct io_uring_sq *sq = &ring.sq;
+	unsigned ktail, mask, index;
+	unsigned sq_entries;
+	unsigned completed, dropped;
+
+	if (argc > 1)
+		return 0;
+
+	ret = io_uring_queue_init(IORING_MAX_ENTRIES, &ring, 0);
+	if (ret < 0) {
+		perror("io_uring_queue_init");
+		exit(1);
+	}
+	mask = *sq->kring_mask;
+
+	/* invalid flags */
+	status |= try_io_uring_enter(ring.ring_fd, 1, 0, ~0U, NULL, -1, EINVAL);
+
+	/* invalid fd, EBADF */
+	status |= try_io_uring_enter(-1, 0, 0, 0, NULL, -1, EBADF);
+
+	/* valid, non-ring fd, EOPNOTSUPP */
+	status |= try_io_uring_enter(0, 0, 0, 0, NULL, -1, EOPNOTSUPP);
+
+	/* to_submit: 0, flags: 0;  should get back 0. */
+	status |= try_io_uring_enter(ring.ring_fd, 1, 0, 0, NULL, 0, 0);
+
+	/* fill the sq ring */
+	sq_entries = *ring.sq.kring_entries;
+	submit_io(&ring, sq_entries);
+	printf("Waiting for %u events\n", sq_entries);
+	ret = __sys_io_uring_enter(ring.ring_fd, 0, sq_entries,
+					IORING_ENTER_GETEVENTS, NULL);
+	if (ret < 0) {
+		perror("io_uring_enter");
+		status = 1;
+	} else {
+		/*
+		 * This is a non-IOPOLL ring, which means that io_uring_enter
+		 * should not return until min_complete events are available
+		 * in the completion queue.
+		 */
+		completed = *ring.cq.ktail - *ring.cq.khead;
+		if (completed != sq_entries) {
+			printf("Submitted %u I/Os, but only got %u completions\n",
+			       sq_entries, completed);
+			status = 1;
+		}
+		reap_events(&ring, sq_entries);
+	}
+
+	/*
+	 * Add an invalid index to the submission queue.  This should
+	 * result in the dropped counter increasing.
+	 */
+	printf("Submitting invalid sqe index.\n");
+	index = *sq->kring_entries + 1; // invalid index
+	dropped = *sq->kdropped;
+	ktail = *sq->ktail;
+	sq->array[ktail & mask] = index;
+	++ktail;
+	/*
+	 * Ensure that the kernel sees the SQE update before it sees the tail
+	 * update.
+	 */
+	io_uring_smp_store_release(sq->ktail, ktail);
+
+	ret = __sys_io_uring_enter(ring.ring_fd, 1, 0, 0, NULL);
+	/* now check to see if our sqe was dropped */
+	if (*sq->kdropped == dropped) {
+		printf("dropped counter did not increase\n");
+		status = 1;
+	}
+
+	if (!status) {
+		printf("PASS\n");
+		return 0;
+	}
+
+	printf("FAIL\n");
+	return -1;
+}
diff --git a/test/io_uring_register.c b/test/io_uring_register.c
new file mode 100644
index 0000000..53e3987
--- /dev/null
+++ b/test/io_uring_register.c
@@ -0,0 +1,658 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * io_uring_register.c
+ *
+ * Description: Unit tests for the io_uring_register system call.
+ *
+ * Copyright 2019, Red Hat, Inc.
+ * Author: Jeff Moyer <jmoyer@redhat.com>
+ */
+#include <stdio.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/sysinfo.h>
+#include <poll.h>
+#include <assert.h>
+#include <sys/uio.h>
+#include <sys/mman.h>
+#include <linux/mman.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <limits.h>
+
+#include "helpers.h"
+#include "liburing.h"
+#include "../src/syscall.h"
+
+static int pagesize;
+static rlim_t mlock_limit;
+static int devnull;
+
+int
+expect_fail(int fd, unsigned int opcode, void *arg,
+	    unsigned int nr_args, int error)
+{
+	int ret;
+
+	printf("io_uring_register(%d, %u, %p, %u)\n",
+	       fd, opcode, arg, nr_args);
+	ret = __sys_io_uring_register(fd, opcode, arg, nr_args);
+	if (ret != -1) {
+		int ret2 = 0;
+
+		printf("expected %s, but call succeeded\n", strerror(error));
+		if (opcode == IORING_REGISTER_BUFFERS) {
+			ret2 = __sys_io_uring_register(fd,
+					IORING_UNREGISTER_BUFFERS, 0, 0);
+		} else if (opcode == IORING_REGISTER_FILES) {
+			ret2 = __sys_io_uring_register(fd,
+					IORING_UNREGISTER_FILES, 0, 0);
+		}
+		if (ret2) {
+			printf("internal error: failed to unregister\n");
+			exit(1);
+		}
+		return 1;
+	}
+
+	if (errno != error) {
+		printf("expected %d, got %d\n", error, errno);
+		return 1;
+	}
+	return 0;
+}
+
+int
+new_io_uring(int entries, struct io_uring_params *p)
+{
+	int fd;
+
+	fd = __sys_io_uring_setup(entries, p);
+	if (fd < 0) {
+		perror("io_uring_setup");
+		exit(1);
+	}
+	return fd;
+}
+
+#define MAXFDS (UINT_MAX * sizeof(int))
+
+void *
+map_filebacked(size_t size)
+{
+	int fd, ret;
+	void *addr;
+	char template[32] = "io_uring_register-test-XXXXXXXX";
+
+	fd = mkstemp(template);
+	if (fd < 0) {
+		perror("mkstemp");
+		return NULL;
+	}
+	unlink(template);
+
+	ret = ftruncate(fd, size);
+	if (ret < 0) {
+		perror("ftruncate");
+		close(fd);
+		return NULL;
+	}
+
+	addr = mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
+	if (addr == MAP_FAILED) {
+		perror("mmap");
+		close(fd);
+		return NULL;
+	}
+
+	close(fd);
+	return addr;
+}
+
+/*
+ * NOTE: this is now limited by SCM_MAX_FD (253).  Keep the code for now,
+ * but probably should augment it to test 253 and 254, specifically.
+ */
+int
+test_max_fds(int uring_fd)
+{
+	int status = 1;
+	int ret;
+	void *fd_as; /* file descriptor address space */
+	int fdtable_fd; /* fd for the file that will be mapped over and over */
+	int io_fd; /* the valid fd for I/O -- /dev/null */
+	int *fds; /* used to map the file into the address space */
+	char template[32] = "io_uring_register-test-XXXXXXXX";
+	unsigned long long i, nr_maps, nr_fds;
+
+	/*
+	 * First, mmap anonymous the full size.  That will guarantee the
+	 * mapping will fit in the memory area selected by mmap.  Then,
+	 * over-write that mapping using a file-backed mapping, 128MiB at
+	 * a time using MAP_FIXED.
+	 */
+	fd_as = mmap(NULL, UINT_MAX * sizeof(int), PROT_READ|PROT_WRITE,
+		     MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
+	if (fd_as == MAP_FAILED) {
+		if (errno == ENOMEM) {
+			printf("Not enough memory for this test, skipping\n");
+			return 0;
+		}
+		perror("mmap fd_as");
+		exit(1);
+	}
+	printf("allocated %zu bytes of address space\n", UINT_MAX * sizeof(int));
+
+	fdtable_fd = mkstemp(template);
+	if (fdtable_fd < 0) {
+		perror("mkstemp");
+		exit(1);
+	}
+	unlink(template);
+	ret = ftruncate(fdtable_fd, 128*1024*1024);
+	if (ret < 0) {
+		perror("ftruncate");
+		exit(1);
+	}
+
+	io_fd = open("/dev/null", O_RDWR);
+	if (io_fd < 0) {
+		perror("open /dev/null");
+		exit(1);
+	}
+	fds = mmap(fd_as, 128*1024*1024, PROT_READ|PROT_WRITE,
+		   MAP_SHARED|MAP_FI