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| author | Shaohua Li <shli@kernel.org> | 2012-10-08 16:32:18 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-10-09 16:22:46 +0900 |
| commit | e79bee24fd6134f90af4228cfebd010136d67631 (patch) | |
| tree | ecc678106bbf4672becca8f798aaf94276eaa2c4 /arch/x86 | |
| parent | 435b405c06119d93333738172b8060b0ed12af41 (diff) | |
| download | kernel_goldelico_gta04-e79bee24fd6134f90af4228cfebd010136d67631.zip kernel_goldelico_gta04-e79bee24fd6134f90af4228cfebd010136d67631.tar.gz kernel_goldelico_gta04-e79bee24fd6134f90af4228cfebd010136d67631.tar.bz2 | |
atomic: implement generic atomic_dec_if_positive()
The x86 implementation of atomic_dec_if_positive is quite generic, so make
it available to all architectures.
This is needed for "swap: add a simple detector for inappropriate swapin
readahead".
[akpm@linux-foundation.org: do the "#define foo foo" trick in the conventional manner]
Signed-off-by: Shaohua Li <shli@fusionio.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michal Simek <monstr@monstr.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/include/asm/atomic.h | 24 |
1 files changed, 0 insertions, 24 deletions
diff --git a/arch/x86/include/asm/atomic.h b/arch/x86/include/asm/atomic.h index 250b877..b6c3b82 100644 --- a/arch/x86/include/asm/atomic.h +++ b/arch/x86/include/asm/atomic.h @@ -240,30 +240,6 @@ static inline int __atomic_add_unless(atomic_t *v, int a, int u) return c; } - -/* - * atomic_dec_if_positive - decrement by 1 if old value positive - * @v: pointer of type atomic_t - * - * The function returns the old value of *v minus 1, even if - * the atomic variable, v, was not decremented. - */ -static inline int atomic_dec_if_positive(atomic_t *v) -{ - int c, old, dec; - c = atomic_read(v); - for (;;) { - dec = c - 1; - if (unlikely(dec < 0)) - break; - old = atomic_cmpxchg((v), c, dec); - if (likely(old == c)) - break; - c = old; - } - return dec; -} - /** * atomic_inc_short - increment of a short integer * @v: pointer to type int |