diff options
Diffstat (limited to 'include/linux/atomic.h')
| -rw-r--r-- | include/linux/atomic.h | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/include/linux/atomic.h b/include/linux/atomic.h index 301de78d65f7..df4f369254c0 100644 --- a/include/linux/atomic.h +++ b/include/linux/atomic.h @@ -34,20 +34,29 @@ * The idea here is to build acquire/release variants by adding explicit * barriers on top of the relaxed variant. In the case where the relaxed * variant is already fully ordered, no additional barriers are needed. + * + * Besides, if an arch has a special barrier for acquire/release, it could + * implement its own __atomic_op_* and use the same framework for building + * variants */ +#ifndef __atomic_op_acquire #define __atomic_op_acquire(op, args...) \ ({ \ typeof(op##_relaxed(args)) __ret = op##_relaxed(args); \ smp_mb__after_atomic(); \ __ret; \ }) +#endif +#ifndef __atomic_op_release #define __atomic_op_release(op, args...) \ ({ \ smp_mb__before_atomic(); \ op##_relaxed(args); \ }) +#endif +#ifndef __atomic_op_fence #define __atomic_op_fence(op, args...) \ ({ \ typeof(op##_relaxed(args)) __ret; \ @@ -56,6 +65,7 @@ smp_mb__after_atomic(); \ __ret; \ }) +#endif /* atomic_add_return_relaxed */ #ifndef atomic_add_return_relaxed @@ -548,6 +558,27 @@ static inline int atomic_dec_if_positive(atomic_t *v) } #endif +/** + * fetch_or - perform *ptr |= mask and return old value of *ptr + * @ptr: pointer to value + * @mask: mask to OR on the value + * + * cmpxchg based fetch_or, macro so it works for different integer types + */ +#ifndef fetch_or +#define fetch_or(ptr, mask) \ +({ typeof(*(ptr)) __old, __val = *(ptr); \ + for (;;) { \ + __old = cmpxchg((ptr), __val, __val | (mask)); \ + if (__old == __val) \ + break; \ + __val = __old; \ + } \ + __old; \ +}) +#endif + + #ifdef CONFIG_GENERIC_ATOMIC64 #include <asm-generic/atomic64.h> #endif |