[tip:locking/core] locking/arch, s390: Add __down_read_killable()

[tip-bot for Kirill Tkhai]

Commit-ID:  a61ba2c8a48f150f5e6b6d14328fc7f1aa32969d
Gitweb:     https://git.kernel.org/tip/a61ba2c8a48f150f5e6b6d14328fc7f1aa32969d
Author:     Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
AuthorDate: Fri, 29 Sep 2017 19:06:18 +0300
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 10 Oct 2017 11:50:15 +0200

locking/arch, s390: Add __down_read_killable()

Similar to __down_write_killable(), and read killable primitive.

Signed-off-by: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: arnd@xxxxxxxx
Cc: avagin@xxxxxxxxxxxxx
Cc: davem@xxxxxxxxxxxxx
Cc: fenghua.yu@xxxxxxxxx
Cc: gorcunov@xxxxxxxxxxxxx
Cc: heiko.carstens@xxxxxxxxxx
Cc: hpa@xxxxxxxxx
Cc: ink@xxxxxxxxxxxxxxxxxxxx
Cc: mattst88@xxxxxxxxx
Cc: rientjes@xxxxxxxxxx
Cc: rth@xxxxxxxxxxx
Cc: schwidefsky@xxxxxxxxxx
Cc: tony.luck@xxxxxxxxx
Cc: viro@xxxxxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/150670117817.23930.13068785028558453848.stgit@xxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 arch/s390/include/asm/rwsem.h | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/arch/s390/include/asm/rwsem.h b/arch/s390/include/asm/rwsem.h
index 597e7e9..fda9481 100644
--- a/arch/s390/include/asm/rwsem.h
+++ b/arch/s390/include/asm/rwsem.h
@@ -49,7 +49,7 @@
 /*
  * lock for reading
  */
-static inline void __down_read(struct rw_semaphore *sem)
+static inline int ___down_read(struct rw_semaphore *sem)
 {
 	signed long old, new;
 
@@ -62,10 +62,25 @@ static inline void __down_read(struct rw_semaphore *sem)
 		: "=&d" (old), "=&d" (new), "=Q" (sem->count)
 		: "Q" (sem->count), "i" (RWSEM_ACTIVE_READ_BIAS)
 		: "cc", "memory");
-	if (old < 0)
+	return (old < 0);
+}
+
+static inline void __down_read(struct rw_semaphore *sem)
+{
+	if (___down_read(sem))
 		rwsem_down_read_failed(sem);
 }
 
+static inline int __down_read_killable(struct rw_semaphore *sem)
+{
+	if (___down_read(sem)) {
+		if (IS_ERR(rwsem_down_read_failed_killable(sem)))
+			return -EINTR;
+	}
+
+	return 0;
+}
+
 /*
  * trylock for reading -- returns 1 if successful, 0 if contention
  */