tree 1e338ba0381c552e60df447ecbc8a6707cf7452f
parent dbea3ce55ad13ddccf519a95ce0d77a5064e9ccc
author Maarten Lankhorst <maarten.lankhorst@linux.intel.com> 1462365506 +0200
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1466788702 -0700

drm/core: Do not preserve framebuffer on rmfb, v4.

commit f2d580b9a8149735cbc4b59c4a8df60173658140 upstream.

It turns out that preserving framebuffers after the rmfb call breaks
vmwgfx userspace. This was originally introduced because it was thought
nobody relied on the behavior, but unfortunately it seems there are
exceptions.

drm_framebuffer_remove may fail with -EINTR now, so a straight revert
is impossible. There is no way to remove the framebuffer from the lists
and active planes without introducing a race because of the different
locking requirements. Instead call drm_framebuffer_remove from a
workqueue, which is unaffected by signals.

Changes since v1:
- Add comment.
Changes since v2:
- Add fastpath for refcount = 1. (danvet)
Changes since v3:
- Rebased.
- Restore lastclose framebuffer removal too.

Fixes: 13803132818c ("drm/core: Preserve the framebuffer after removing it.")
Testcase: kms_rmfb_basic
References: https://lists.freedesktop.org/archives/dri-devel/2016-March/102876.html
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Cc: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Tested-by: Thomas Hellstrom <thellstrom@vmware.com> #v3
Tested-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/6c63ca37-0e7e-ac7f-a6d2-c7822e3d611f@linux.intel.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>