locking/rwsem, s390: Provide __down_write_killable()

Introduce ___down_write() for the fast path and reuse it for __down_write()
resp. __down_write_killable() each using the respective generic slow path
(rwsem_down_write_failed() resp. rwsem_down_write_failed_killable()).

Signed-off-by: Michal Hocko <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Chris Zankel <[email protected]>
Cc: David S. Miller <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Max Filippov <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Signed-off-by: Davidlohr Bueso <[email protected]>
Cc: Signed-off-by: Jason Low <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

1 files changed, 17 insertions, 2 deletions

diff --git a/arch/s390/include/asm/rwsem.h b/arch/s390/include/asm/rwsem.h
index 555d23b6b6d1..c75e4471e618 100644
--- a/arch/s390/include/asm/rwsem.h
+++ b/arch/s390/include/asm/rwsem.h
@@ -90,7 +90,7 @@ static inline int __down_read_trylock(struct rw_semaphore *sem)
 /*
  * lock for writing
  */
-static inline void __down_write(struct rw_semaphore *sem)
+static inline long ___down_write(struct rw_semaphore *sem)
 {
 	signed long old, new, tmp;
 
@@ -104,10 +104,25 @@ static inline void __down_write(struct rw_semaphore *sem)
 		: "=&d" (old), "=&d" (new), "=Q" (sem->count)
 		: "Q" (sem->count), "m" (tmp)
 		: "cc", "memory");
-	if (old != 0)
+
+	return old;
+}
+
+static inline void __down_write(struct rw_semaphore *sem)
+{
+	if (___down_write(sem))
 		rwsem_down_write_failed(sem);
 }
 
+static inline int __down_write_killable(struct rw_semaphore *sem)
+{
+	if (___down_write(sem))
+		if (IS_ERR(rwsem_down_write_failed_killable(sem)))
+			return -EINTR;
+
+	return 0;
+}
+
 /*
  * trylock for writing -- returns 1 if successful, 0 if contention
  */