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authorAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>2011-08-02 12:02:51 +0530
committerKevin Wolf <kwolf@redhat.com>2011-08-23 14:15:17 +0200
commit12888904fe7f0231e853072805fb2317ec60c510 (patch)
tree90bf670880786873109be0bbb0c34533cc8397e1 /qemu-coroutine-lock.c
parentb861b7419c49ad53e786062b4fbf6da53468f130 (diff)
coroutine: Add CoRwlock support
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'qemu-coroutine-lock.c')
-rw-r--r--qemu-coroutine-lock.c44
1 files changed, 44 insertions, 0 deletions
diff --git a/qemu-coroutine-lock.c b/qemu-coroutine-lock.c
index a80f437c59..2a385a3bb8 100644
--- a/qemu-coroutine-lock.c
+++ b/qemu-coroutine-lock.c
@@ -115,3 +115,47 @@ void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex)
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;
+ while (!qemu_co_queue_empty(&lock->queue)) {
+ /*
+ * Wakeup every body. This will include some
+ * writers too.
+ */
+ qemu_co_queue_next(&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;
+}