From 4a6dae6d382e9edf3ff440b819e554ed706359bc Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Sun, 13 Nov 2005 16:07:24 -0800 Subject: [PATCH] atomic: cmpxchg Introduce an atomic_cmpxchg operation. Signed-off-by: Nick Piggin Cc: "Paul E. McKenney" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/asm-v850/atomic.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'include/asm-v850') 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() -- cgit v1.2.2