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| author | Nick Piggin <nickpiggin@yahoo.com.au> | 2005-11-13 16:07:24 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-11-13 18:14:16 -0800 |
| commit | 4a6dae6d382e9edf3ff440b819e554ed706359bc (patch) | |
| tree | 2945a5095973e2ecf05b503d6deb859083045b8e /include/asm-sh | |
| parent | 53e86b91b7ae66d4c2757195cbd42e00d9199cf2 (diff) | |
| download | lwn-4a6dae6d382e9edf3ff440b819e554ed706359bc.tar.gz lwn-4a6dae6d382e9edf3ff440b819e554ed706359bc.zip | |
[PATCH] atomic: cmpxchg
Introduce an atomic_cmpxchg operation.
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 | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/include/asm-sh/atomic.h b/include/asm-sh/atomic.h index 3c4f805da1ac..a148c762d366 100644 --- a/include/asm-sh/atomic.h +++ b/include/asm-sh/atomic.h @@ -87,6 +87,20 @@ static __inline__ int atomic_sub_return(int i, atomic_t * v) #define atomic_inc(v) atomic_add(1,(v)) #define atomic_dec(v) atomic_sub(1,(v)) +static inline int atomic_cmpxchg(atomic_t *v, int old, int new) +{ + int ret; + unsigned long flags; + + local_irq_save(flags); + ret = v->counter; + if (likely(ret == old)) + v->counter = new; + local_irq_restore(flags); + + return ret; +} + static __inline__ void atomic_clear_mask(unsigned int mask, atomic_t *v) { unsigned long flags; |