diff options
author | Ingo Molnar <mingo@elte.hu> | 2008-10-24 12:48:46 +0200 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-10-24 12:48:46 +0200 |
commit | 8c82a17e9c924c0e9f13e75e4c2f6bca19a4b516 (patch) | |
tree | d535f46a917e14e90deccb29ad00aac016ad18dd /include/asm-generic/mutex-dec.h | |
parent | 4ce72a2c063a7fa8e42a9435440ae3364115a58d (diff) | |
parent | 57f8f7b60db6f1ed2c6918ab9230c4623a9dbe37 (diff) |
Merge commit 'v2.6.28-rc1' into sched/urgent
Diffstat (limited to 'include/asm-generic/mutex-dec.h')
-rw-r--r-- | include/asm-generic/mutex-dec.h | 26 |
1 files changed, 2 insertions, 24 deletions
diff --git a/include/asm-generic/mutex-dec.h b/include/asm-generic/mutex-dec.h index ed108be6743..f104af7cf43 100644 --- a/include/asm-generic/mutex-dec.h +++ b/include/asm-generic/mutex-dec.h @@ -22,8 +22,6 @@ __mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *)) { if (unlikely(atomic_dec_return(count) < 0)) fail_fn(count); - else - smp_mb(); } /** @@ -41,10 +39,7 @@ __mutex_fastpath_lock_retval(atomic_t *count, int (*fail_fn)(atomic_t *)) { if (unlikely(atomic_dec_return(count) < 0)) return fail_fn(count); - else { - smp_mb(); - return 0; - } + return 0; } /** @@ -63,7 +58,6 @@ __mutex_fastpath_lock_retval(atomic_t *count, int (*fail_fn)(atomic_t *)) static inline void __mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *)) { - smp_mb(); if (unlikely(atomic_inc_return(count) <= 0)) fail_fn(count); } @@ -88,25 +82,9 @@ __mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *)) static inline int __mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *)) { - /* - * We have two variants here. The cmpxchg based one is the best one - * because it never induce a false contention state. It is included - * here because architectures using the inc/dec algorithms over the - * xchg ones are much more likely to support cmpxchg natively. - * - * If not we fall back to the spinlock based variant - that is - * just as efficient (and simpler) as a 'destructive' probing of - * the mutex state would be. - */ -#ifdef __HAVE_ARCH_CMPXCHG - if (likely(atomic_cmpxchg(count, 1, 0) == 1)) { - smp_mb(); + if (likely(atomic_cmpxchg(count, 1, 0) == 1)) return 1; - } return 0; -#else - return fail_fn(count); -#endif } #endif |