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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-v850 | |
| 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-v850')
| -rw-r--r-- | include/asm-v850/atomic.h | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/include/asm-v850/atomic.h b/include/asm-v850/atomic.h index 395268a8c0de..e497166ca42b 100644 --- a/include/asm-v850/atomic.h +++ b/include/asm-v850/atomic.h @@ -90,6 +90,20 @@ static __inline__ void atomic_clear_mask (unsigned long mask, unsigned long *add #define atomic_dec_and_test(v) (atomic_sub_return (1, (v)) == 0) #define atomic_add_negative(i,v) (atomic_add_return ((i), (v)) < 0) +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; +} + /* Atomic operations are already serializing on ARM */ #define smp_mb__before_atomic_dec() barrier() #define smp_mb__after_atomic_dec() barrier() |