diff mbox series

[PULL,51/74] seqlock: add QemuLockable support

Message ID 1534870966-9287-52-git-send-email-pbonzini@redhat.com
State New
Headers show
Series [PULL,01/74] tests: virtio: separate ccw tests from libqos | expand

Commit Message

Paolo Bonzini Aug. 21, 2018, 5:02 p.m. UTC 
A shortcut when the seqlock write is protected by a spinlock or any mutex
other than the BQL.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 include/qemu/seqlock.h | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
diff mbox series

Patch

diff --git a/include/qemu/seqlock.h b/include/qemu/seqlock.h
index c367516..fd408b7 100644
--- a/include/qemu/seqlock.h
+++ b/include/qemu/seqlock.h
@@ -16,6 +16,7 @@ 
 
 #include "qemu/atomic.h"
 #include "qemu/thread.h"
+#include "qemu/lockable.h"
 
 typedef struct QemuSeqLock QemuSeqLock;
 
@@ -45,6 +46,25 @@  static inline void seqlock_write_end(QemuSeqLock *sl)
     atomic_set(&sl->sequence, sl->sequence + 1);
 }
 
+/* Lock out other writers and update the count.  */
+static inline void seqlock_write_lock_impl(QemuSeqLock *sl, QemuLockable *lock)
+{
+    qemu_lockable_lock(lock);
+    seqlock_write_begin(sl);
+}
+#define seqlock_write_lock(sl, lock) \
+    seqlock_write_lock_impl(sl, QEMU_MAKE_LOCKABLE(lock))
+
+/* Lock out other writers and update the count.  */
+static inline void seqlock_write_unlock_impl(QemuSeqLock *sl, QemuLockable *lock)
+{
+    qemu_lockable_unlock(lock);
+    seqlock_write_begin(sl);
+}
+#define seqlock_write_unlock(sl, lock) \
+    seqlock_write_unlock_impl(sl, QEMU_MAKE_LOCKABLE(lock))
+
+
 static inline unsigned seqlock_read_begin(const QemuSeqLock *sl)
 {
     /* Always fail if a write is in progress.  */