[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>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/asm-m68k/atomic.h b/include/asm-m68k/atomic.h
index 38f3043e7fe1..b821975a361a 100644
--- a/include/asm-m68k/atomic.h
+++ b/include/asm-m68k/atomic.h
@@ -139,6 +139,8 @@ static inline void atomic_set_mask(unsigned long mask, unsigned long *v)
         __asm__ __volatile__("orl %1,%0" : "+m" (*v) : "id" (mask));
 }
 
+#define atomic_cmpxchg(v, o, n) ((int)cmpxchg(&((v)->counter), (o), (n)))
+
 /* Atomic operations are already serializing */
 #define smp_mb__before_atomic_dec()     barrier()
 #define smp_mb__after_atomic_dec()      barrier()