diff options
author | Jiri Kosina <jkosina@suse.cz> | 2010-12-22 18:57:02 +0100 |
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committer | Jiri Kosina <jkosina@suse.cz> | 2010-12-22 18:57:02 +0100 |
commit | 4b7bd364700d9ac8372eff48832062b936d0793b (patch) | |
tree | 0dbf78c95456a0b02d07fcd473281f04a87e266d /include/linux/atomic.h | |
parent | c0d8768af260e2cbb4bf659ae6094a262c86b085 (diff) | |
parent | 90a8a73c06cc32b609a880d48449d7083327e11a (diff) |
Merge branch 'master' into for-next
Conflicts:
MAINTAINERS
arch/arm/mach-omap2/pm24xx.c
drivers/scsi/bfa/bfa_fcpim.c
Needed to update to apply fixes for which the old branch was too
outdated.
Diffstat (limited to 'include/linux/atomic.h')
-rw-r--r-- | include/linux/atomic.h | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/include/linux/atomic.h b/include/linux/atomic.h new file mode 100644 index 00000000000..96c038e43d6 --- /dev/null +++ b/include/linux/atomic.h @@ -0,0 +1,37 @@ +#ifndef _LINUX_ATOMIC_H +#define _LINUX_ATOMIC_H +#include <asm/atomic.h> + +/** + * atomic_inc_not_zero_hint - increment if not null + * @v: pointer of type atomic_t + * @hint: probable value of the atomic before the increment + * + * This version of atomic_inc_not_zero() gives a hint of probable + * value of the atomic. This helps processor to not read the memory + * before doing the atomic read/modify/write cycle, lowering + * number of bus transactions on some arches. + * + * Returns: 0 if increment was not done, 1 otherwise. + */ +#ifndef atomic_inc_not_zero_hint +static inline int atomic_inc_not_zero_hint(atomic_t *v, int hint) +{ + int val, c = hint; + + /* sanity test, should be removed by compiler if hint is a constant */ + if (!hint) + return atomic_inc_not_zero(v); + + do { + val = atomic_cmpxchg(v, c, c + 1); + if (val == c) + return 1; + c = val; + } while (c); + + return 0; +} +#endif + +#endif /* _LINUX_ATOMIC_H */ |