2 * coroutine queues and locks
4 * Copyright (c) 2011 Kevin Wolf <kwolf@redhat.com>
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11 * furnished to do so, subject to the following conditions:
13 * The above copyright notice and this permission notice shall be included in
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17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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25 #include "qemu/osdep.h"
26 #include "qemu-common.h"
27 #include "qemu/coroutine.h"
28 #include "qemu/coroutine_int.h"
29 #include "qemu/queue.h"
32 void qemu_co_queue_init(CoQueue *queue)
34 QTAILQ_INIT(&queue->entries);
37 void coroutine_fn qemu_co_queue_wait(CoQueue *queue)
39 Coroutine *self = qemu_coroutine_self();
40 QTAILQ_INSERT_TAIL(&queue->entries, self, co_queue_next);
41 qemu_coroutine_yield();
42 assert(qemu_in_coroutine());
46 * qemu_co_queue_run_restart:
48 * Enter each coroutine that was previously marked for restart by
49 * qemu_co_queue_next() or qemu_co_queue_restart_all(). This function is
50 * invoked by the core coroutine code when the current coroutine yields or
53 void qemu_co_queue_run_restart(Coroutine *co)
57 trace_qemu_co_queue_run_restart(co);
58 while ((next = QTAILQ_FIRST(&co->co_queue_wakeup))) {
59 QTAILQ_REMOVE(&co->co_queue_wakeup, next, co_queue_next);
60 qemu_coroutine_enter(next, NULL);
64 static bool qemu_co_queue_do_restart(CoQueue *queue, bool single)
66 Coroutine *self = qemu_coroutine_self();
69 if (QTAILQ_EMPTY(&queue->entries)) {
73 while ((next = QTAILQ_FIRST(&queue->entries)) != NULL) {
74 QTAILQ_REMOVE(&queue->entries, next, co_queue_next);
75 QTAILQ_INSERT_TAIL(&self->co_queue_wakeup, next, co_queue_next);
76 trace_qemu_co_queue_next(next);
84 bool coroutine_fn qemu_co_queue_next(CoQueue *queue)
86 assert(qemu_in_coroutine());
87 return qemu_co_queue_do_restart(queue, true);
90 void coroutine_fn qemu_co_queue_restart_all(CoQueue *queue)
92 assert(qemu_in_coroutine());
93 qemu_co_queue_do_restart(queue, false);
96 bool qemu_co_enter_next(CoQueue *queue)
100 next = QTAILQ_FIRST(&queue->entries);
105 QTAILQ_REMOVE(&queue->entries, next, co_queue_next);
106 qemu_coroutine_enter(next, NULL);
110 bool qemu_co_queue_empty(CoQueue *queue)
112 return QTAILQ_FIRST(&queue->entries) == NULL;
115 void qemu_co_mutex_init(CoMutex *mutex)
117 memset(mutex, 0, sizeof(*mutex));
118 qemu_co_queue_init(&mutex->queue);
121 void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex)
123 Coroutine *self = qemu_coroutine_self();
125 trace_qemu_co_mutex_lock_entry(mutex, self);
127 while (mutex->locked) {
128 qemu_co_queue_wait(&mutex->queue);
131 mutex->locked = true;
133 trace_qemu_co_mutex_lock_return(mutex, self);
136 void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex)
138 Coroutine *self = qemu_coroutine_self();
140 trace_qemu_co_mutex_unlock_entry(mutex, self);
142 assert(mutex->locked == true);
143 assert(qemu_in_coroutine());
145 mutex->locked = false;
146 qemu_co_queue_next(&mutex->queue);
148 trace_qemu_co_mutex_unlock_return(mutex, self);
151 void qemu_co_rwlock_init(CoRwlock *lock)
153 memset(lock, 0, sizeof(*lock));
154 qemu_co_queue_init(&lock->queue);
157 void qemu_co_rwlock_rdlock(CoRwlock *lock)
159 while (lock->writer) {
160 qemu_co_queue_wait(&lock->queue);
165 void qemu_co_rwlock_unlock(CoRwlock *lock)
167 assert(qemu_in_coroutine());
169 lock->writer = false;
170 qemu_co_queue_restart_all(&lock->queue);
173 assert(lock->reader >= 0);
174 /* Wakeup only one waiting writer */
176 qemu_co_queue_next(&lock->queue);
181 void qemu_co_rwlock_wrlock(CoRwlock *lock)
183 while (lock->writer || lock->reader) {
184 qemu_co_queue_wait(&lock->queue);