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From: Pranith Kumar <pranith@gatech.edu>
To: peterz@infradead.org
Cc: linux-kernel@vger.kernel.org
Subject: [RFC PATCH 1/1] remove redundant compare, cmpxchg already does it
Date: Wed, 04 Jun 2014 16:38:55 -0400	[thread overview]
Message-ID: <538F83DF.8090303@gatech.edu> (raw)

remove a redundant comparision

Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
---
 kernel/locking/rwsem-xadd.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c
index 1f99664b..6f8bd3c 100644
--- a/kernel/locking/rwsem-xadd.c
+++ b/kernel/locking/rwsem-xadd.c
@@ -249,8 +249,7 @@ static inline bool rwsem_try_write_lock(long count, struct rw_semaphore *sem)
 {
     if (!(count & RWSEM_ACTIVE_MASK)) {
         /* try acquiring the write lock */
-        if (sem->count == RWSEM_WAITING_BIAS &&
-            cmpxchg(&sem->count, RWSEM_WAITING_BIAS,
+        if (cmpxchg(&sem->count, RWSEM_WAITING_BIAS,
                 RWSEM_ACTIVE_WRITE_BIAS) == RWSEM_WAITING_BIAS) {
             if (!list_is_singular(&sem->wait_list))
                 rwsem_atomic_update(RWSEM_WAITING_BIAS, sem);
-- 
1.9.1

             reply	other threads:[~2014-06-04 20:48 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-04 20:38 Pranith Kumar [this message]
2014-06-04 20:56 ` [RFC PATCH 1/1] remove redundant compare, cmpxchg already does it Andev
2014-06-05  7:22   ` Peter Zijlstra
2014-06-05 17:54     ` Davidlohr Bueso
2014-06-05 18:08       ` Davidlohr Bueso
2014-06-06  7:01         ` Peter Zijlstra
2014-06-06  3:09     ` Pranith Kumar

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