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author | Ingo Molnar <mingo@elte.hu> | 2009-01-11 15:34:05 +0100 |
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committer | Ingo Molnar <mingo@elte.hu> | 2009-01-11 15:34:05 +0100 |
commit | d19b85db9d5c44a4c21dcb10d6fbadaa4425ab2a (patch) | |
tree | 250be7a5a29069f7d1f4524fa45ab0e988833025 /arch/blackfin/include/asm/mutex.h | |
parent | 490dea45d00f01847ebebd007685d564aaf2cd98 (diff) | |
parent | c59765042f53a79a7a65585042ff463b69cb248c (diff) |
Merge commit 'v2.6.29-rc1' into timers/urgent
Diffstat (limited to 'arch/blackfin/include/asm/mutex.h')
-rw-r--r-- | arch/blackfin/include/asm/mutex.h | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/arch/blackfin/include/asm/mutex.h b/arch/blackfin/include/asm/mutex.h index 458c1f7fbc1..5d399256bf0 100644 --- a/arch/blackfin/include/asm/mutex.h +++ b/arch/blackfin/include/asm/mutex.h @@ -6,4 +6,67 @@ * implementation. (see asm-generic/mutex-xchg.h for details) */ +#ifndef _ASM_MUTEX_H +#define _ASM_MUTEX_H + +#ifndef CONFIG_SMP #include <asm-generic/mutex-dec.h> +#else + +static inline void +__mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *)) +{ + if (unlikely(atomic_dec_return(count) < 0)) + fail_fn(count); + else + smp_mb(); +} + +static inline int +__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; + } +} + +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); +} + +#define __mutex_slowpath_needs_to_unlock() 1 + +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(); + return 1; + } + return 0; +#else + return fail_fn(count); +#endif +} + +#endif + +#endif |