[PATCH] mutex subsystem, add atomic_xchg() to all arches

add atomic_xchg() to all the architectures. Needed by the new mutex code.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/asm-x86_64/atomic.h b/include/asm-x86_64/atomic.h
index 72eb071488c7..6b540237a2f8 100644
--- a/include/asm-x86_64/atomic.h
+++ b/include/asm-x86_64/atomic.h
@@ -389,6 +389,7 @@ static __inline__ long atomic64_sub_return(long i, atomic64_t *v)
 #define atomic64_dec_return(v)  (atomic64_sub_return(1,v))
 
 #define atomic_cmpxchg(v, old, new) ((int)cmpxchg(&((v)->counter), old, new))
+#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
 
 /**
  * atomic_add_unless - add unless the number is a given value