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| author | Nick Piggin <nickpiggin@yahoo.com.au> | 2005-11-13 16:07:25 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-11-13 18:14:16 -0800 |
| commit | 8426e1f6af0fd7f44d040af7263750c5a52f3cc3 (patch) | |
| tree | 827bd2588c2b73d11cea6869de8ff42dba134375 /include/asm-sh | |
| parent | 4a6dae6d382e9edf3ff440b819e554ed706359bc (diff) | |
| download | lwn-8426e1f6af0fd7f44d040af7263750c5a52f3cc3.tar.gz lwn-8426e1f6af0fd7f44d040af7263750c5a52f3cc3.zip | |
[PATCH] atomic: inc_not_zero
Introduce an atomic_inc_not_zero operation. Make this a special case of
atomic_add_unless because lockless pagecache actually wants
atomic_inc_not_negativeone due to its offset refcount.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/asm-sh')
| -rw-r--r-- | include/asm-sh/atomic.h | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/include/asm-sh/atomic.h b/include/asm-sh/atomic.h index a148c762d366..aabfd334462c 100644 --- a/include/asm-sh/atomic.h +++ b/include/asm-sh/atomic.h @@ -101,6 +101,21 @@ static inline int atomic_cmpxchg(atomic_t *v, int old, int new) return ret; } +static inline int atomic_add_unless(atomic_t *v, int a, int u) +{ + int ret; + unsigned long flags; + + local_irq_save(flags); + ret = v->counter; + if (ret != u) + v->counter += a; + local_irq_restore(flags); + + return ret != u; +} +#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) + static __inline__ void atomic_clear_mask(unsigned int mask, atomic_t *v) { unsigned long flags; |