From: Peter Zijlstra <peterz@infradead.org>
Date: Wed, 18 May 2016 10:42:21 +0000 (+0200)
Subject: locking/atomic, arch/rwsem: Employ atomic_long_fetch_add()
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=86a3b5f34fc1fb307abef4fde76bebd3edce0324;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

locking/atomic, arch/rwsem: Employ atomic_long_fetch_add()

Now that we have fetch_add() we can stop using add_return() - val.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jason Low <jason.low2@hpe.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <waiman.long@hpe.com>
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---

diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c
index 2031281bb940..447e08de1fab 100644
--- a/kernel/locking/rwsem-xadd.c
+++ b/kernel/locking/rwsem-xadd.c
@@ -153,7 +153,7 @@ __rwsem_mark_wake(struct rw_semaphore *sem,
 	if (wake_type != RWSEM_WAKE_READ_OWNED) {
 		adjustment = RWSEM_ACTIVE_READ_BIAS;
  try_reader_grant:
-		oldcount = atomic_long_add_return(adjustment, &sem->count) - adjustment;
+		oldcount = atomic_long_fetch_add(adjustment, &sem->count);
 
 		if (unlikely(oldcount < RWSEM_WAITING_BIAS)) {
 			/*