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-rw-r--r--include/asm-powerpc/atomic.h38
1 files changed, 24 insertions, 14 deletions
diff --git a/include/asm-powerpc/atomic.h b/include/asm-powerpc/atomic.h
index 147a38dcc76..bb3c0ab7e66 100644
--- a/include/asm-powerpc/atomic.h
+++ b/include/asm-powerpc/atomic.h
@@ -8,6 +8,7 @@
typedef struct { volatile int counter; } atomic_t;
#ifdef __KERNEL__
+#include <linux/compiler.h>
#include <asm/synch.h>
#include <asm/asm-compat.h>
@@ -176,20 +177,29 @@ static __inline__ int atomic_dec_return(atomic_t *v)
* Atomically adds @a to @v, so long as it was not @u.
* Returns non-zero if @v was not @u, and zero otherwise.
*/
-#define atomic_add_unless(v, a, u) \
-({ \
- int c, old; \
- c = atomic_read(v); \
- for (;;) { \
- if (unlikely(c == (u))) \
- break; \
- old = atomic_cmpxchg((v), c, c + (a)); \
- if (likely(old == c)) \
- break; \
- c = old; \
- } \
- c != (u); \
-})
+static __inline__ int atomic_add_unless(atomic_t *v, int a, int u)
+{
+ int t;
+
+ __asm__ __volatile__ (
+ LWSYNC_ON_SMP
+"1: lwarx %0,0,%1 # atomic_add_unless\n\
+ cmpw 0,%0,%3 \n\
+ beq- 2f \n\
+ add %0,%2,%0 \n"
+ PPC405_ERR77(0,%2)
+" stwcx. %0,0,%1 \n\
+ bne- 1b \n"
+ ISYNC_ON_SMP
+" subf %0,%2,%0 \n\
+2:"
+ : "=&r" (t)
+ : "r" (&v->counter), "r" (a), "r" (u)
+ : "cc", "memory");
+
+ return t != u;
+}
+
#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
#define atomic_sub_and_test(a, v) (atomic_sub_return((a), (v)) == 0)