From ad46276952f1af34cd91d46d49ba13d347d56367 Mon Sep 17 00:00:00 2001
From: Jiri Olsa <jolsa@redhat.com>
Date: Wed, 8 Jul 2009 12:10:31 +0000
Subject: memory barrier: adding smp_mb__after_lock

Adding smp_mb__after_lock define to be used as a smp_mb call after
a lock.

Making it nop for x86, since {read|write|spin}_lock() on x86 are
full memory barriers.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 include/linux/spinlock.h | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'include/linux/spinlock.h')

diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h
index 252b245cfcf..4be57ab0347 100644
--- a/include/linux/spinlock.h
+++ b/include/linux/spinlock.h
@@ -132,6 +132,11 @@ do {								\
 #endif /*__raw_spin_is_contended*/
 #endif
 
+/* The lock does not imply full memory barrier. */
+#ifndef ARCH_HAS_SMP_MB_AFTER_LOCK
+static inline void smp_mb__after_lock(void) { smp_mb(); }
+#endif
+
 /**
  * spin_unlock_wait - wait until the spinlock gets unlocked
  * @lock: the spinlock in question.
-- 
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