| /* |
| * coroutine queues and locks |
| * |
| * Copyright (c) 2011 Kevin Wolf <kwolf@redhat.com> |
| * |
| * 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. |
| */ |
| |
| #include "qemu/osdep.h" |
| #include "qemu-common.h" |
| #include "qemu/coroutine.h" |
| #include "qemu/coroutine_int.h" |
| #include "qemu/queue.h" |
| #include "trace.h" |
| |
| void qemu_co_queue_init(CoQueue *queue) |
| { |
| QSIMPLEQ_INIT(&queue->entries); |
| } |
| |
| void coroutine_fn qemu_co_queue_wait(CoQueue *queue) |
| { |
| Coroutine *self = qemu_coroutine_self(); |
| QSIMPLEQ_INSERT_TAIL(&queue->entries, self, co_queue_next); |
| qemu_coroutine_yield(); |
| assert(qemu_in_coroutine()); |
| } |
| |
| /** |
| * qemu_co_queue_run_restart: |
| * |
| * Enter each coroutine that was previously marked for restart by |
| * qemu_co_queue_next() or qemu_co_queue_restart_all(). This function is |
| * invoked by the core coroutine code when the current coroutine yields or |
| * terminates. |
| */ |
| void qemu_co_queue_run_restart(Coroutine *co) |
| { |
| Coroutine *next; |
| |
| trace_qemu_co_queue_run_restart(co); |
| while ((next = QSIMPLEQ_FIRST(&co->co_queue_wakeup))) { |
| QSIMPLEQ_REMOVE_HEAD(&co->co_queue_wakeup, co_queue_next); |
| qemu_coroutine_enter(next); |
| } |
| } |
| |
| static bool qemu_co_queue_do_restart(CoQueue *queue, bool single) |
| { |
| Coroutine *self = qemu_coroutine_self(); |
| Coroutine *next; |
| |
| if (QSIMPLEQ_EMPTY(&queue->entries)) { |
| return false; |
| } |
| |
| while ((next = QSIMPLEQ_FIRST(&queue->entries)) != NULL) { |
| QSIMPLEQ_REMOVE_HEAD(&queue->entries, co_queue_next); |
| QSIMPLEQ_INSERT_TAIL(&self->co_queue_wakeup, next, co_queue_next); |
| trace_qemu_co_queue_next(next); |
| if (single) { |
| break; |
| } |
| } |
| return true; |
| } |
| |
| bool coroutine_fn qemu_co_queue_next(CoQueue *queue) |
| { |
| assert(qemu_in_coroutine()); |
| return qemu_co_queue_do_restart(queue, true); |
| } |
| |
| void coroutine_fn qemu_co_queue_restart_all(CoQueue *queue) |
| { |
| assert(qemu_in_coroutine()); |
| qemu_co_queue_do_restart(queue, false); |
| } |
| |
| bool qemu_co_enter_next(CoQueue *queue) |
| { |
| Coroutine *next; |
| |
| next = QSIMPLEQ_FIRST(&queue->entries); |
| if (!next) { |
| return false; |
| } |
| |
| QSIMPLEQ_REMOVE_HEAD(&queue->entries, co_queue_next); |
| qemu_coroutine_enter(next); |
| return true; |
| } |
| |
| bool qemu_co_queue_empty(CoQueue *queue) |
| { |
| return QSIMPLEQ_FIRST(&queue->entries) == NULL; |
| } |
| |
| void qemu_co_mutex_init(CoMutex *mutex) |
| { |
| memset(mutex, 0, sizeof(*mutex)); |
| qemu_co_queue_init(&mutex->queue); |
| } |
| |
| void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex) |
| { |
| Coroutine *self = qemu_coroutine_self(); |
| |
| trace_qemu_co_mutex_lock_entry(mutex, self); |
| |
| while (mutex->locked) { |
| qemu_co_queue_wait(&mutex->queue); |
| } |
| |
| mutex->locked = true; |
| |
| trace_qemu_co_mutex_lock_return(mutex, self); |
| } |
| |
| void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex) |
| { |
| Coroutine *self = qemu_coroutine_self(); |
| |
| trace_qemu_co_mutex_unlock_entry(mutex, self); |
| |
| assert(mutex->locked == true); |
| assert(qemu_in_coroutine()); |
| |
| mutex->locked = false; |
| qemu_co_queue_next(&mutex->queue); |
| |
| trace_qemu_co_mutex_unlock_return(mutex, self); |
| } |
| |
| void qemu_co_rwlock_init(CoRwlock *lock) |
| { |
| memset(lock, 0, sizeof(*lock)); |
| qemu_co_queue_init(&lock->queue); |
| } |
| |
| void qemu_co_rwlock_rdlock(CoRwlock *lock) |
| { |
| while (lock->writer) { |
| qemu_co_queue_wait(&lock->queue); |
| } |
| lock->reader++; |
| } |
| |
| void qemu_co_rwlock_unlock(CoRwlock *lock) |
| { |
| assert(qemu_in_coroutine()); |
| if (lock->writer) { |
| lock->writer = false; |
| qemu_co_queue_restart_all(&lock->queue); |
| } else { |
| lock->reader--; |
| assert(lock->reader >= 0); |
| /* Wakeup only one waiting writer */ |
| if (!lock->reader) { |
| qemu_co_queue_next(&lock->queue); |
| } |
| } |
| } |
| |
| void qemu_co_rwlock_wrlock(CoRwlock *lock) |
| { |
| while (lock->writer || lock->reader) { |
| qemu_co_queue_wait(&lock->queue); |
| } |
| lock->writer = true; |
| } |