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memory barrier: adding smp_mb__after_lock

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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>
This commit is contained in:
Jiri Olsa
2009-07-08 12:10:31 +00:00
committed by David S. Miller
parent a57de0b433
commit ad46276952
3 changed files with 13 additions and 1 deletions
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5
include/linux/spinlock.h
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@ -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.