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authorShaohua Li <shli@kernel.org>2012-10-08 16:32:18 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-10-09 16:22:46 +0900
commite79bee24fd6134f90af4228cfebd010136d67631 (patch)
treeecc678106bbf4672becca8f798aaf94276eaa2c4 /arch/x86/include/asm/atomic.h
parent435b405c06119d93333738172b8060b0ed12af41 (diff)
downloadlinux-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/include/asm/atomic.h')
-rw-r--r--arch/x86/include/asm/atomic.h24
1 files changed, 0 insertions, 24 deletions
diff --git a/arch/x86/include/asm/atomic.h b/arch/x86/include/asm/atomic.h
index 250b8774c158..b6c3b821acf6 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