diff options
Diffstat (limited to 'arch/sh/include/asm/atomic-llsc.h')
| -rw-r--r-- | arch/sh/include/asm/atomic-llsc.h | 27 |
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 4b00b78e3f4..b040e1e0861 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 */ |