From 3f2546b2ef55b661fd8dd69682b38992225e86f6 Mon Sep 17 00:00:00 2001 From: fishsoupisgood Date: Mon, 29 Apr 2019 01:17:54 +0100 Subject: Initial import of qemu-2.4.1 --- qemu-coroutine-lock.c | 186 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 186 insertions(+) create mode 100644 qemu-coroutine-lock.c (limited to 'qemu-coroutine-lock.c') diff --git a/qemu-coroutine-lock.c b/qemu-coroutine-lock.c new file mode 100644 index 00000000..6b490333 --- /dev/null +++ b/qemu-coroutine-lock.c @@ -0,0 +1,186 @@ +/* + * coroutine queues and locks + * + * Copyright (c) 2011 Kevin Wolf + * + * 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-common.h" +#include "block/coroutine.h" +#include "block/coroutine_int.h" +#include "qemu/queue.h" +#include "trace.h" + +void qemu_co_queue_init(CoQueue *queue) +{ + QTAILQ_INIT(&queue->entries); +} + +void coroutine_fn qemu_co_queue_wait(CoQueue *queue) +{ + Coroutine *self = qemu_coroutine_self(); + QTAILQ_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 = QTAILQ_FIRST(&co->co_queue_wakeup))) { + QTAILQ_REMOVE(&co->co_queue_wakeup, next, co_queue_next); + qemu_coroutine_enter(next, NULL); + } +} + +static bool qemu_co_queue_do_restart(CoQueue *queue, bool single) +{ + Coroutine *self = qemu_coroutine_self(); + Coroutine *next; + + if (QTAILQ_EMPTY(&queue->entries)) { + return false; + } + + while ((next = QTAILQ_FIRST(&queue->entries)) != NULL) { + QTAILQ_REMOVE(&queue->entries, next, co_queue_next); + QTAILQ_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 = QTAILQ_FIRST(&queue->entries); + if (!next) { + return false; + } + + QTAILQ_REMOVE(&queue->entries, next, co_queue_next); + qemu_coroutine_enter(next, NULL); + return true; +} + +bool qemu_co_queue_empty(CoQueue *queue) +{ + return QTAILQ_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; +} -- cgit v1.2.3