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authorDaniel P. Berrange <berrange@redhat.com>2015-09-01 14:48:02 +0100
committerDaniel P. Berrange <berrange@redhat.com>2015-10-20 14:59:04 +0100
commit10817bf09d5f8cb22711fb0ee8d8da49f6f05f89 (patch)
tree735f6b70cedecd57843b9108cb68e2359e147e0c /util/qemu-coroutine-lock.c
parent57cb38b3833c5215131b983f181b26d6ba9b8d35 (diff)
coroutine: move into libqemuutil.a library
The coroutine files are currently referenced by the block-obj-y variable. The coroutine functionality though is already used by more than just the block code. eg migration code uses coroutine yield. In the future the I/O channel code will also use the coroutine yield functionality. Since the coroutine code is nicely self-contained it can be easily built as part of the libqemuutil.a library, making it widely available. The headers are also moved into include/qemu, instead of the include/block directory, since they are now part of the util codebase, and the impl was never in the block/ directory either. Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Diffstat (limited to 'util/qemu-coroutine-lock.c')
-rw-r--r--util/qemu-coroutine-lock.c186
1 files changed, 186 insertions, 0 deletions
diff --git a/util/qemu-coroutine-lock.c b/util/qemu-coroutine-lock.c
new file mode 100644
index 0000000000..130ee19d17
--- /dev/null
+++ b/util/qemu-coroutine-lock.c
@@ -0,0 +1,186 @@
+/*
+ * 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-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)
+{
+ 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;
+}