[PATCH 01/09] atomic.h : Add atomic64 cmpxchg, xchg and add_unless to alpha

[Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>]

atomic.h : Add atomic64 cmpxchg, xchg and add_unless to alpha

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

--- a/include/asm-alpha/atomic.h
+++ b/include/asm-alpha/atomic.h
@@ -175,19 +175,64 @@ static __inline__ long atomic64_sub_return(long i, atomic64_t * v)
 	return result;
 }
 
-#define atomic_cmpxchg(v, o, n) ((int)cmpxchg(&((v)->counter), (o), (n)))
+#define atomic64_cmpxchg(v, old, new) \
+	((__typeof__((v)->counter))cmpxchg(&((v)->counter), old, new))
+#define atomic64_xchg(v, new) (xchg(&((v)->counter), new))
+
+#define atomic_cmpxchg(v, old, new) \
+	((__typeof__((v)->counter))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
+ * @v: pointer of type atomic_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 atomic_add_unless(v, a, u)				\
 ({								\
-	int c, old;						\
+	__typeof__((v)->counter) c, old;			\
 	c = atomic_read(v);					\
-	while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c) \
+	for (;;) {						\
+		if (unlikely(c == (u)))				\
+			break;					\
+		old = atomic_cmpxchg((v), c, c + (a));		\
+		if (likely(old == c))				\
+			break;					\
 		c = old;					\
+	}							\
 	c != (u);						\
 })
 #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)
+
 #define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
 #define atomic64_add_negative(a, v) (atomic64_add_return((a), (v)) < 0)