| #ifndef QEMU_RCU_H |
| #define QEMU_RCU_H |
| |
| /* |
| * urcu-mb.h |
| * |
| * Userspace RCU header with explicit memory barrier. |
| * |
| * 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 |
| * |
| * IBM's contributions to this file may be relicensed under LGPLv2 or later. |
| */ |
| |
| |
| #include "qemu/thread.h" |
| #include "qemu/thread_local.h" |
| #include "qemu/queue.h" |
| #include "qemu/atomic.h" |
| #include "qemu/sys_membarrier.h" |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| /* |
| * Important ! |
| * |
| * Each thread containing read-side critical sections must be registered |
| * with rcu_register_thread() before calling rcu_read_lock(). |
| * rcu_unregister_thread() should be called before the thread exits. |
| */ |
| |
| #ifdef DEBUG_RCU |
| #define rcu_assert(args...) assert(args) |
| #else |
| #define rcu_assert(args...) |
| #endif |
| |
| /* |
| * Global quiescent period counter with low-order bits unused. |
| * Using a int rather than a char to eliminate false register dependencies |
| * causing stalls on some architectures. |
| */ |
| extern unsigned long rcu_gp_ctr; |
| |
| extern QemuEvent rcu_gp_event; |
| |
| struct rcu_reader_data { |
| /* Data used by both reader and synchronize_rcu() */ |
| unsigned long ctr; |
| bool waiting; |
| |
| /* Data used by reader only */ |
| unsigned depth; |
| |
| /* Data used for registry, protected by rcu_registry_lock */ |
| QLIST_ENTRY(rcu_reader_data) node; |
| }; |
| |
| QEMU_THREAD_LOCAL_EXTERN(struct rcu_reader_data, rcu_reader); |
| |
| void rcu_read_lock(void); |
| |
| void rcu_read_unlock(void); |
| |
| extern void synchronize_rcu(void); |
| |
| /* |
| * Reader thread registration. |
| */ |
| extern void rcu_register_thread(void); |
| extern void rcu_unregister_thread(void); |
| |
| /* |
| * Support for fork(). fork() support is enabled at startup. |
| */ |
| extern void rcu_enable_atfork(void); |
| extern void rcu_disable_atfork(void); |
| |
| struct rcu_head; |
| typedef void RCUCBFunc(struct rcu_head *head); |
| |
| struct rcu_head { |
| struct rcu_head *next; |
| RCUCBFunc *func; |
| }; |
| |
| extern void call_rcu1(struct rcu_head *head, RCUCBFunc *func); |
| |
| /* The operands of the minus operator must have the same type, |
| * which must be the one that we specify in the cast. |
| */ |
| #define call_rcu(head, func, field) \ |
| call_rcu1(({ \ |
| char __attribute__((unused)) \ |
| offset_must_be_zero[-offsetof(typeof(*(head)), field)], \ |
| func_type_invalid = (func) - (void (*)(typeof(head)))(func); \ |
| &(head)->field; \ |
| }), \ |
| (RCUCBFunc *)(func)) |
| |
| #define g_free_rcu(obj, field) \ |
| call_rcu1(({ \ |
| char __attribute__((unused)) \ |
| offset_must_be_zero[-offsetof(typeof(*(obj)), field)]; \ |
| &(obj)->field; \ |
| }), \ |
| (RCUCBFunc *)g_free); |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| #endif /* QEMU_RCU_H */ |