Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com>
---
qemu-coroutine-lock.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
qemu-coroutine.h | 12 ++++++++++++
2 files changed, 56 insertions(+), 0 deletions(-)
diff --git a/qemu-coroutine-lock.c b/qemu-coroutine-lock.c
index 5071fb8..5ecaa94 100644
--- a/qemu-coroutine-lock.c
+++ b/qemu-coroutine-lock.c
@@ -115,3 +115,47 @@ void 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--;;
+ assert(lock->writer == 0);
+ 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 */
+ 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++;
+ assert(lock->writer == 1);
+}
diff --git a/qemu-coroutine.h b/qemu-coroutine.h
index 71cfa5a..a9735fb 100644
--- a/qemu-coroutine.h
+++ b/qemu-coroutine.h
@@ -17,6 +17,7 @@
#include <stdbool.h>
#include "qemu-queue.h"
+#include "qemu-thread.h"
/**
* Coroutines are a mechanism for stack switching and can be used for
@@ -114,4 +115,15 @@ void qemu_co_mutex_init(CoMutex *mutex);
void qemu_co_mutex_lock(CoMutex *mutex);
void qemu_co_mutex_unlock(CoMutex *mutex);
+typedef struct CoRwlock {
+ bool writer;
+ int reader;
+ CoQueue queue;
+} CoRwlock;
+
+void qemu_co_rwlock_init(CoRwlock *lock);
+void qemu_co_rwlock_rdlock(CoRwlock *lock);
+void qemu_co_rwlock_wrlock(CoRwlock *lock);
+void qemu_co_rwlock_unlock(CoRwlock *lock);
+
#endif /* QEMU_COROUTINE_H */
--
1.7.4.1
