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Subject[PATCH 10/10] atomic.h : Add atomic64 cmpxchg, xchg and add_unless to x86_64
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atomic.h : Add atomic64 cmpxchg, xchg and add_unless to x86_64

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>

--- a/include/asm-x86_64/atomic.h
+++ b/include/asm-x86_64/atomic.h
@@ -375,8 +375,8 @@ static __inline__ long atomic64_add_return(long i, atomic64_t *v)
long __i = i;
__asm__ __volatile__(
LOCK_PREFIX "xaddq %0, %1;"
- :"=r"(i)
- :"m"(v->counter), "0"(i));
+ :"+r" (i), "+m" (v->counter)
+ : : "memory");
return i + __i;
}

@@ -388,7 +388,10 @@ static __inline__ long atomic64_sub_return(long i, atomic64_t *v)
#define atomic64_inc_return(v) (atomic64_add_return(1,v))
#define atomic64_dec_return(v) (atomic64_sub_return(1,v))

-#define atomic_cmpxchg(v, old, new) ((int)cmpxchg(&((v)->counter), old, new))
+#define atomic64_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), old, new))
+#define atomic64_xchg(v, new) (xchg(&((v)->counter), new))
+
+#define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), old, new))
#define atomic_xchg(v, new) (xchg(&((v)->counter), new))

/**
@@ -402,7 +405,7 @@ static __inline__ long atomic64_sub_return(long i, atomic64_t *v)
*/
#define atomic_add_unless(v, a, u) \
({ \
- int c, old; \
+ __typeof__((v)->counter) c, old; \
c = atomic_read(v); \
for (;;) { \
if (unlikely(c == (u))) \
@@ -416,6 +419,31 @@ static __inline__ long atomic64_sub_return(long i, atomic64_t *v)
})
#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)

+/**
+ * atomic64_add_unless - add unless the number is a given value
+ * @v: pointer of type atomic64_t
+ * @a: the amount to add to v...
+ * @u: ...unless v is equal to u.
+ *
+ * Atomically adds @a to @v, so long as it was not @u.
+ * Returns non-zero if @v was not @u, and zero otherwise.
+ */
+#define atomic64_add_unless(v, a, u) \
+({ \
+ __typeof__((v)->counter) c, old; \
+ c = atomic64_read(v); \
+ for (;;) { \
+ if (unlikely(c == (u))) \
+ break; \
+ old = atomic64_cmpxchg((v), c, c + (a)); \
+ if (likely(old == c)) \
+ break; \
+ c = old; \
+ } \
+ c != (u); \
+})
+#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
+
/* These are x86-specific, used by some header files */
#define atomic_clear_mask(mask, addr) \
__asm__ __volatile__(LOCK_PREFIX "andl %0,%1" \
-
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