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Diffstat (limited to 'arch/sh/include/asm/atomic-llsc.h')
-rw-r--r--arch/sh/include/asm/atomic-llsc.h27
1 files changed, 27 insertions, 0 deletions
diff --git a/arch/sh/include/asm/atomic-llsc.h b/arch/sh/include/asm/atomic-llsc.h
index 4b00b78e3f4f..b040e1e08610 100644
--- a/arch/sh/include/asm/atomic-llsc.h
+++ b/arch/sh/include/asm/atomic-llsc.h
@@ -104,4 +104,31 @@ static inline void atomic_set_mask(unsigned int mask, atomic_t *v)
: "t");
}
+#define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))
+
+/**
+ * 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.
+ */
+static inline int atomic_add_unless(atomic_t *v, int a, int 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;
+ }
+
+ return c != (u);
+}
+
#endif /* __ASM_SH_ATOMIC_LLSC_H */