[PATCH] powerpc: Extends HCALL interface for InfiniBand usage

[pandora-kernel.git] / include / asm-powerpc / atomic.h

diff --git a/include/asm-powerpc/atomic.h b/include/asm-powerpc/atomic.h
index 9ce51ba..bb3c0ab 100644 (file)
--- 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)