coroutines: Locks
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/qemu-coroutine-lock.c b/qemu-coroutine-lock.c
new file mode 100644
index 0000000..abaa1f7
--- /dev/null
+++ b/qemu-coroutine-lock.c
@@ -0,0 +1,124 @@
+/*
+ * 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"
+
+static QTAILQ_HEAD(, Coroutine) unlock_bh_queue =
+ QTAILQ_HEAD_INITIALIZER(unlock_bh_queue);
+
+struct unlock_bh {
+ QEMUBH *bh;
+};
+
+static void qemu_co_queue_next_bh(void *opaque)
+{
+ struct unlock_bh *unlock_bh = opaque;
+ Coroutine *next;
+
+ trace_qemu_co_queue_next_bh();
+ while ((next = QTAILQ_FIRST(&unlock_bh_queue))) {
+ QTAILQ_REMOVE(&unlock_bh_queue, next, co_queue_next);
+ qemu_coroutine_enter(next, NULL);
+ }
+
+ qemu_bh_delete(unlock_bh->bh);
+ qemu_free(unlock_bh);
+}
+
+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());
+}
+
+bool qemu_co_queue_next(CoQueue *queue)
+{
+ struct unlock_bh *unlock_bh;
+ Coroutine *next;
+
+ next = QTAILQ_FIRST(&queue->entries);
+ if (next) {
+ QTAILQ_REMOVE(&queue->entries, next, co_queue_next);
+ QTAILQ_INSERT_TAIL(&unlock_bh_queue, next, co_queue_next);
+ trace_qemu_co_queue_next(next);
+
+ unlock_bh = qemu_malloc(sizeof(*unlock_bh));
+ unlock_bh->bh = qemu_bh_new(qemu_co_queue_next_bh, unlock_bh);
+ qemu_bh_schedule(unlock_bh->bh);
+ }
+
+ return (next != NULL);
+}
+
+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);
+}
