root / qemu-coroutine-lock.c @ 2ff3de68
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/*
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* coroutine queues and locks
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*
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* Copyright (c) 2011 Kevin Wolf <kwolf@redhat.com>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "qemu-common.h" |
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#include "block/coroutine.h" |
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#include "block/coroutine_int.h" |
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#include "qemu/queue.h" |
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#include "trace.h" |
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void qemu_co_queue_init(CoQueue *queue)
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{ |
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QTAILQ_INIT(&queue->entries); |
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} |
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void coroutine_fn qemu_co_queue_wait(CoQueue *queue)
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{ |
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Coroutine *self = qemu_coroutine_self(); |
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QTAILQ_INSERT_TAIL(&queue->entries, self, co_queue_next); |
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qemu_coroutine_yield(); |
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assert(qemu_in_coroutine()); |
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} |
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void coroutine_fn qemu_co_queue_wait_insert_head(CoQueue *queue)
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{ |
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Coroutine *self = qemu_coroutine_self(); |
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QTAILQ_INSERT_HEAD(&queue->entries, self, co_queue_next); |
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qemu_coroutine_yield(); |
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assert(qemu_in_coroutine()); |
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} |
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/**
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* qemu_co_queue_run_restart:
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*
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* Enter each coroutine that was previously marked for restart by
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* qemu_co_queue_next() or qemu_co_queue_restart_all(). This function is
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* invoked by the core coroutine code when the current coroutine yields or
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* terminates.
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*/
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void qemu_co_queue_run_restart(Coroutine *co)
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{ |
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Coroutine *next; |
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trace_qemu_co_queue_run_restart(co); |
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while ((next = QTAILQ_FIRST(&co->co_queue_wakeup))) {
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QTAILQ_REMOVE(&co->co_queue_wakeup, next, co_queue_next); |
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qemu_coroutine_enter(next, NULL);
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} |
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} |
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static bool qemu_co_queue_do_restart(CoQueue *queue, bool single) |
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{ |
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Coroutine *self = qemu_coroutine_self(); |
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Coroutine *next; |
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if (QTAILQ_EMPTY(&queue->entries)) {
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return false; |
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} |
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while ((next = QTAILQ_FIRST(&queue->entries)) != NULL) { |
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QTAILQ_REMOVE(&queue->entries, next, co_queue_next); |
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QTAILQ_INSERT_TAIL(&self->co_queue_wakeup, next, co_queue_next); |
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trace_qemu_co_queue_next(next); |
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if (single) {
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break;
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} |
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} |
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return true; |
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} |
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bool qemu_co_queue_next(CoQueue *queue)
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{ |
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return qemu_co_queue_do_restart(queue, true); |
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} |
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void qemu_co_queue_restart_all(CoQueue *queue)
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{ |
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qemu_co_queue_do_restart(queue, false);
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} |
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bool qemu_co_queue_empty(CoQueue *queue)
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{ |
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return (QTAILQ_FIRST(&queue->entries) == NULL); |
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} |
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void qemu_co_mutex_init(CoMutex *mutex)
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{ |
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memset(mutex, 0, sizeof(*mutex)); |
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qemu_co_queue_init(&mutex->queue); |
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} |
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void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex)
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{ |
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Coroutine *self = qemu_coroutine_self(); |
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trace_qemu_co_mutex_lock_entry(mutex, self); |
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while (mutex->locked) {
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qemu_co_queue_wait(&mutex->queue); |
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} |
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mutex->locked = true;
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trace_qemu_co_mutex_lock_return(mutex, self); |
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} |
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void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex)
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{ |
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Coroutine *self = qemu_coroutine_self(); |
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trace_qemu_co_mutex_unlock_entry(mutex, self); |
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assert(mutex->locked == true);
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assert(qemu_in_coroutine()); |
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mutex->locked = false;
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qemu_co_queue_next(&mutex->queue); |
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trace_qemu_co_mutex_unlock_return(mutex, self); |
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} |
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void qemu_co_rwlock_init(CoRwlock *lock)
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{ |
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memset(lock, 0, sizeof(*lock)); |
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qemu_co_queue_init(&lock->queue); |
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} |
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void qemu_co_rwlock_rdlock(CoRwlock *lock)
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{ |
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while (lock->writer) {
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qemu_co_queue_wait(&lock->queue); |
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} |
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lock->reader++; |
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} |
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void qemu_co_rwlock_unlock(CoRwlock *lock)
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{ |
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assert(qemu_in_coroutine()); |
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if (lock->writer) {
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lock->writer = false;
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qemu_co_queue_restart_all(&lock->queue); |
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} else {
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lock->reader--; |
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assert(lock->reader >= 0);
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/* Wakeup only one waiting writer */
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if (!lock->reader) {
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qemu_co_queue_next(&lock->queue); |
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} |
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} |
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} |
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void qemu_co_rwlock_wrlock(CoRwlock *lock)
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{ |
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while (lock->writer || lock->reader) {
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qemu_co_queue_wait(&lock->queue); |
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} |
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lock->writer = true;
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} |