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[Qemu-devel] [PATCH 01/30] coroutine: Add CoRwlock support
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PATCH 01/30] coroutine: Add CoRwlock support |
Date: |
Mon, 29 Aug 2011 16:53:09 +0200 |
From: "Aneesh Kumar K.V" <address@hidden>
Signed-off-by: Aneesh Kumar K.V <address@hidden>
Signed-off-by: Kevin Wolf <address@hidden>
---
qemu-coroutine-lock.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
qemu-coroutine.h | 32 ++++++++++++++++++++++++++++++++
2 files changed, 76 insertions(+), 0 deletions(-)
diff --git a/qemu-coroutine-lock.c b/qemu-coroutine-lock.c
index a80f437..2a385a3 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;
+}
diff --git a/qemu-coroutine.h b/qemu-coroutine.h
index 2f2fd95..b8fc4f4 100644
--- a/qemu-coroutine.h
+++ b/qemu-coroutine.h
@@ -156,4 +156,36 @@ void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex);
*/
void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex);
+typedef struct CoRwlock {
+ bool writer;
+ int reader;
+ CoQueue queue;
+} CoRwlock;
+
+/**
+ * Initialises a CoRwlock. This must be called before any other operation
+ * is used on the CoRwlock
+ */
+void qemu_co_rwlock_init(CoRwlock *lock);
+
+/**
+ * Read locks the CoRwlock. If the lock cannot be taken immediately because
+ * of a parallel writer, control is transferred to the caller of the current
+ * coroutine.
+ */
+void qemu_co_rwlock_rdlock(CoRwlock *lock);
+
+/**
+ * Write Locks the mutex. If the lock cannot be taken immediately because
+ * of a parallel reader, control is transferred to the caller of the current
+ * coroutine.
+ */
+void qemu_co_rwlock_wrlock(CoRwlock *lock);
+
+/**
+ * Unlocks the read/write lock and schedules the next coroutine that was
+ * waiting for this lock to be run.
+ */
+void qemu_co_rwlock_unlock(CoRwlock *lock);
+
#endif /* QEMU_COROUTINE_H */
--
1.7.6
- [Qemu-devel] [PULL 00/30] Block patches, Kevin Wolf, 2011/08/29
- [Qemu-devel] [PATCH 02/30] block: parse cache mode flags in a single place, Kevin Wolf, 2011/08/29
- [Qemu-devel] [PATCH 01/30] coroutine: Add CoRwlock support,
Kevin Wolf <=
- [Qemu-devel] [PATCH 06/30] qcow2: fix typo in documentation for qcow2_get_cluster_offset(), Kevin Wolf, 2011/08/29
- [Qemu-devel] [PATCH 03/30] block: add cache=directsync parameter to -drive, Kevin Wolf, 2011/08/29
- [Qemu-devel] [PATCH 07/30] qcow: initialize coroutine mutex, Kevin Wolf, 2011/08/29
- [Qemu-devel] [PATCH 04/30] qcow2: Fix DEBUG_* compilation, Kevin Wolf, 2011/08/29
- [Qemu-devel] [PATCH 05/30] qemu-img: Use qemu_blockalign, Kevin Wolf, 2011/08/29
- [Qemu-devel] [PATCH 09/30] block/curl: Handle failed reads gracefully., Kevin Wolf, 2011/08/29
- [Qemu-devel] [PATCH 11/30] posix-aio-compat: fix latency issues, Kevin Wolf, 2011/08/29
- [Qemu-devel] [PATCH 10/30] block: include flush requests in info blockstats, Kevin Wolf, 2011/08/29
- [Qemu-devel] [PATCH 12/30] qcow/qcow2: Allocate QCowAIOCB structure using stack, Kevin Wolf, 2011/08/29
- [Qemu-devel] [PATCH 19/30] qcow2: remove l2meta from QCowAIOCB, Kevin Wolf, 2011/08/29