[PATCH V10 2/7] locking/percpu-rwsem: Add guard support

[kan . liang]

From: "Peter Zijlstra (Intel)" <peterz@xxxxxxxxxxxxx>

To simplify the usage of the percpu rw semaphore.

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Cc: Dennis Zhou <dennis@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: linux-mm@xxxxxxxxx
---

No changes since V9

 include/linux/percpu-rwsem.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h
index c012df33a9f0..af7d75ede619 100644
--- a/include/linux/percpu-rwsem.h
+++ b/include/linux/percpu-rwsem.h
@@ -8,6 +8,7 @@
 #include <linux/wait.h>
 #include <linux/rcu_sync.h>
 #include <linux/lockdep.h>
+#include <linux/cleanup.h>
 
 struct percpu_rw_semaphore {
 	struct rcu_sync		rss;
@@ -125,6 +126,13 @@ extern bool percpu_is_read_locked(struct percpu_rw_semaphore *);
 extern void percpu_down_write(struct percpu_rw_semaphore *);
 extern void percpu_up_write(struct percpu_rw_semaphore *);
 
+DEFINE_GUARD(percpu_read, struct percpu_rw_semaphore *,
+	     percpu_down_read(_T), percpu_up_read(_T))
+DEFINE_GUARD_COND(percpu_read, _try, percpu_down_read_trylock(_T))
+
+DEFINE_GUARD(percpu_write, struct percpu_rw_semaphore *,
+	     percpu_down_write(_T), percpu_up_write(_T))
+
 static inline bool percpu_is_write_locked(struct percpu_rw_semaphore *sem)
 {
 	return atomic_read(&sem->block);
-- 
2.38.1