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yaml
---
r: 257873
b: refs/heads/master
c: 50f92aa
h: refs/heads/master
i:
  257871: 40aa8b1
v: v3
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Mike Frysinger committed Jul 23, 2011
1 parent 744f54f commit 5806842
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Showing 2 changed files with 2 additions and 77 deletions.
2 changes: 1 addition & 1 deletion [refs]
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---
refs/heads/master: fb1d9be5967fff0a3c93b06304fd992e3c438b7f
refs/heads/master: 50f92aa3348a1c810fa809c60227ec80f7a5fd41
77 changes: 1 addition & 76 deletions trunk/arch/blackfin/include/asm/mutex.h
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/*
* Pull in the generic implementation for the mutex fastpath.
*
* TODO: implement optimized primitives instead, or leave the generic
* implementation in place, or pick the atomic_xchg() based generic
* implementation. (see asm-generic/mutex-xchg.h for details)
*
* Copyright 2006-2009 Analog Devices Inc.
*
* Licensed under the GPL-2 or later.
*/

#ifndef _ASM_MUTEX_H
#define _ASM_MUTEX_H

#ifndef CONFIG_SMP
#include <asm-generic/mutex.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
#include <asm-generic/mutex-dec.h>

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