/* Atomic operations usable in machine independent code */ #ifndef _LINUX_ATOMIC_H #define _LINUX_ATOMIC_H #include #include /* * Relaxed variants of xchg, cmpxchg and some atomic operations. * * We support four variants: * * - Fully ordered: The default implementation, no suffix required. * - Acquire: Provides ACQUIRE semantics, _acquire suffix. * - Release: Provides RELEASE semantics, _release suffix. * - Relaxed: No ordering guarantees, _relaxed suffix. * * For compound atomics performing both a load and a store, ACQUIRE * semantics apply only to the load and RELEASE semantics only to the * store portion of the operation. Note that a failed cmpxchg_acquire * does -not- imply any memory ordering constraints. * * See Documentation/memory-barriers.txt for ACQUIRE/RELEASE definitions. */ #ifndef atomic_read_acquire #define atomic_read_acquire(v) smp_load_acquire(&(v)->counter) #endif #ifndef atomic_set_release #define atomic_set_release(v, i) smp_store_release(&(v)->counter, (i)) #endif /* * 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; \ smp_mb__before_atomic(); \ __ret = op##_relaxed(args); \ smp_mb__after_atomic(); \ __ret; \ }) #endif /* atomic_add_return_relaxed */ #ifndef atomic_add_return_relaxed #define atomic_add_return_relaxed atomic_add_return #define atomic_add_return_acquire atomic_add_return #define atomic_add_return_release atomic_add_return #else /* atomic_add_return_relaxed */ #ifndef atomic_add_return_acquire #define atomic_add_return_acquire(...) \ __atomic_op_acquire(atomic_add_return, __VA_ARGS__) #endif #ifndef atomic_add_return_release #define atomic_add_return_release(...) \ __atomic_op_release(atomic_add_return, __VA_ARGS__) #endif #ifndef atomic_add_return #define atomic_add_return(...) \ __atomic_op_fence(atomic_add_return, __VA_ARGS__) #endif #endif /* atomic_add_return_relaxed */ /* atomic_inc_return_relaxed */ #ifndef atomic_inc_return_relaxed #define atomic_inc_return_relaxed atomic_inc_return #define atomic_inc_return_acquire atomic_inc_return #define atomic_inc_return_release atomic_inc_return #else /* atomic_inc_return_relaxed */ #ifndef atomic_inc_return_acquire #define atomic_inc_return_acquire(...) \ __atomic_op_acquire(atomic_inc_return, __VA_ARGS__) #endif #ifndef atomic_inc_return_release #define atomic_inc_return_release(...) \ __atomic_op_release(atomic_inc_return, __VA_ARGS__) #endif #ifndef atomic_inc_return #define atomic_inc_return(...) \ __atomic_op_fence(atomic_inc_return, __VA_ARGS__) #endif #endif /* atomic_inc_return_relaxed */ /* atomic_sub_return_relaxed */ #ifndef atomic_sub_return_relaxed #define atomic_sub_return_relaxed atomic_sub_return #define atomic_sub_return_acquire atomic_sub_return #define atomic_sub_return_release atomic_sub_return #else /* atomic_sub_return_relaxed */ #ifndef atomic_sub_return_acquire #define atomic_sub_return_acquire(...) \ __atomic_op_acquire(atomic_sub_return, __VA_ARGS__) #endif #ifndef atomic_sub_return_release #define atomic_sub_return_release(...) \ __atomic_op_release(atomic_sub_return, __VA_ARGS__) #endif #ifndef atomic_sub_return #define atomic_sub_return(...) \ __atomic_op_fence(atomic_sub_return, __VA_ARGS__) #endif #endif /* atomic_sub_return_relaxed */ /* atomic_dec_return_relaxed */ #ifndef atomic_dec_return_relaxed #define atomic_dec_return_relaxed atomic_dec_return #define atomic_dec_return_acquire atomic_dec_return #define atomic_dec_return_release atomic_dec_return #else /* atomic_dec_return_relaxed */ #ifndef atomic_dec_return_acquire #define atomic_dec_return_acquire(...) \ __atomic_op_acquire(atomic_dec_return, __VA_ARGS__) #endif #ifndef atomic_dec_return_release #define atomic_dec_return_release(...) \ __atomic_op_release(atomic_dec_return, __VA_ARGS__) #endif #ifndef atomic_dec_return #define atomic_dec_return(...) \ __atomic_op_fence(atomic_dec_return, __VA_ARGS__) #endif #endif /* atomic_dec_return_relaxed */ /* atomic_xchg_relaxed */ #ifndef atomic_xchg_relaxed #define atomic_xchg_relaxed atomic_xchg #define atomic_xchg_acquire atomic_xchg #define atomic_xchg_release atomic_xchg #else /* atomic_xchg_relaxed */ #ifndef atomic_xchg_acquire #define atomic_xchg_acquire(...) \ __atomic_op_acquire(atomic_xchg, __VA_ARGS__) #endif #ifndef atomic_xchg_release #define atomic_xchg_release(...) \ __atomic_op_release(atomic_xchg, __VA_ARGS__) #endif #ifndef atomic_xchg #define atomic_xchg(...) \ __atomic_op_fence(atomic_xchg, __VA_ARGS__) #endif #endif /* atomic_xchg_relaxed */ /* atomic_cmpxchg_relaxed */ #ifndef atomic_cmpxchg_relaxed #define atomic_cmpxchg_relaxed atomic_cmpxchg #define atomic_cmpxchg_acquire atomic_cmpxchg #define atomic_cmpxchg_release atomic_cmpxchg #else /* atomic_cmpxchg_relaxed */ #ifndef atomic_cmpxchg_acquire #define atomic_cmpxchg_acquire(...) \ __atomic_op_acquire(atomic_cmpxchg, __VA_ARGS__) #endif #ifndef atomic_cmpxchg_release #define atomic_cmpxchg_release(...) \ __atomic_op_release(atomic_cmpxchg, __VA_ARGS__) #endif #ifndef atomic_cmpxchg #define atomic_cmpxchg(...) \ __atomic_op_fence(atomic_cmpxchg, __VA_ARGS__) #endif #endif /* atomic_cmpxchg_relaxed */ #ifndef atomic64_read_acquire #define atomic64_read_acquire(v) smp_load_acquire(&(v)->counter) #endif #ifndef atomic64_set_release #define atomic64_set_release(v, i) smp_store_release(&(v)->counter, (i)) #endif /* atomic64_add_return_relaxed */ #ifndef atomic64_add_return_relaxed #define atomic64_add_return_relaxed atomic64_add_return #define atomic64_add_return_acquire atomic64_add_return #define atomic64_add_return_release atomic64_add_return #else /* atomic64_add_return_relaxed */ #ifndef atomic64_add_return_acquire #define atomic64_add_return_acquire(...) \ __atomic_op_acquire(atomic64_add_return, __VA_ARGS__) #endif #ifndef atomic64_add_return_release #define atomic64_add_return_release(...) \ __atomic_op_release(atomic64_add_return, __VA_ARGS__) #endif #ifndef atomic64_add_return #define atomic64_add_return(...) \ __atomic_op_fence(atomic64_add_return, __VA_ARGS__) #endif #endif /* atomic64_add_return_relaxed */ /* atomic64_inc_return_relaxed */ #ifndef atomic64_inc_return_relaxed #define atomic64_inc_return_relaxed atomic64_inc_return #define atomic64_inc_return_acquire atomic64_inc_return #define atomic64_inc_return_release atomic64_inc_return #else /* atomic64_inc_return_relaxed */ #ifndef atomic64_inc_return_acquire #define atomic64_inc_return_acquire(...) \ __atomic_op_acquire(atomic64_inc_return, __VA_ARGS__) #endif #ifndef atomic64_inc_return_release #define atomic64_inc_return_release(...) \ __atomic_op_release(atomic64_inc_return, __VA_ARGS__) #endif #ifndef atomic64_inc_return #define atomic64_inc_return(...) \ __atomic_op_fence(atomic64_inc_return, __VA_ARGS__) #endif #endif /* atomic64_inc_return_relaxed */ /* atomic64_sub_return_relaxed */ #ifndef atomic64_sub_return_relaxed #define atomic64_sub_return_relaxed atomic64_sub_return #define atomic64_sub_return_acquire atomic64_sub_return #define atomic64_sub_return_release atomic64_sub_return #else /* atomic64_sub_return_relaxed */ #ifndef atomic64_sub_return_acquire #define atomic64_sub_return_acquire(...) \ __atomic_op_acquire(atomic64_sub_return, __VA_ARGS__) #endif #ifndef atomic64_sub_return_release #define atomic64_sub_return_release(...) \ __atomic_op_release(atomic64_sub_return, __VA_ARGS__) #endif #ifndef atomic64_sub_return #define atomic64_sub_return(...) \ __atomic_op_fence(atomic64_sub_return, __VA_ARGS__) #endif #endif /* atomic64_sub_return_relaxed */ /* atomic64_dec_return_relaxed */ #ifndef atomic64_dec_return_relaxed #define atomic64_dec_return_relaxed atomic64_dec_return #define atomic64_dec_return_acquire atomic64_dec_return #define atomic64_dec_return_release atomic64_dec_return #else /* atomic64_dec_return_relaxed */ #ifndef atomic64_dec_return_acquire #define atomic64_dec_return_acquire(...) \ __atomic_op_acquire(atomic64_dec_return, __VA_ARGS__) #endif #ifndef atomic64_dec_return_release #define atomic64_dec_return_release(...) \ __atomic_op_release(atomic64_dec_return, __VA_ARGS__) #endif #ifndef atomic64_dec_return #define atomic64_dec_return(...) \ __atomic_op_fence(atomic64_dec_return, __VA_ARGS__) #endif #endif /* atomic64_dec_return_relaxed */ /* atomic64_xchg_relaxed */ #ifndef atomic64_xchg_relaxed #define atomic64_xchg_relaxed atomic64_xchg #define atomic64_xchg_acquire atomic64_xchg #define atomic64_xchg_release atomic64_xchg #else /* atomic64_xchg_relaxed */ #ifndef atomic64_xchg_acquire #define atomic64_xchg_acquire(...) \ __atomic_op_acquire(atomic64_xchg, __VA_ARGS__) #endif #ifndef atomic64_xchg_release #define atomic64_xchg_release(...) \ __atomic_op_release(atomic64_xchg, __VA_ARGS__) #endif #ifndef atomic64_xchg #define atomic64_xchg(...) \ __atomic_op_fence(atomic64_xchg, __VA_ARGS__) #endif #endif /* atomic64_xchg_relaxed */ /* atomic64_cmpxchg_relaxed */ #ifndef atomic64_cmpxchg_relaxed #define atomic64_cmpxchg_relaxed atomic64_cmpxchg #define atomic64_cmpxchg_acquire atomic64_cmpxchg #define atomic64_cmpxchg_release atomic64_cmpxchg #else /* atomic64_cmpxchg_relaxed */ #ifndef atomic64_cmpxchg_acquire #define atomic64_cmpxchg_acquire(...) \ __atomic_op_acquire(atomic64_cmpxchg, __VA_ARGS__) #endif #ifndef atomic64_cmpxchg_release #define atomic64_cmpxchg_release(...) \ __atomic_op_release(atomic64_cmpxchg, __VA_ARGS__) #endif #ifndef atomic64_cmpxchg #define atomic64_cmpxchg(...) \ __atomic_op_fence(atomic64_cmpxchg, __VA_ARGS__) #endif #endif /* atomic64_cmpxchg_relaxed */ /* cmpxchg_relaxed */ #ifndef cmpxchg_relaxed #define cmpxchg_relaxed cmpxchg #define cmpxchg_acquire cmpxchg #define cmpxchg_release cmpxchg #else /* cmpxchg_relaxed */ #ifndef cmpxchg_acquire #define cmpxchg_acquire(...) \ __atomic_op_acquire(cmpxchg, __VA_ARGS__) #endif #ifndef cmpxchg_release #define cmpxchg_release(...) \ __atomic_op_release(cmpxchg, __VA_ARGS__) #endif #ifndef cmpxchg #define cmpxchg(...) \ __atomic_op_fence(cmpxchg, __VA_ARGS__) #endif #endif /* cmpxchg_relaxed */ /* cmpxchg64_relaxed */ #ifndef cmpxchg64_relaxed #define cmpxchg64_relaxed cmpxchg64 #define cmpxchg64_acquire cmpxchg64 #define cmpxchg64_release cmpxchg64 #else /* cmpxchg64_relaxed */ #ifndef cmpxchg64_acquire #define cmpxchg64_acquire(...) \ __atomic_op_acquire(cmpxchg64, __VA_ARGS__) #endif #ifndef cmpxchg64_release #define cmpxchg64_release(...) \ __atomic_op_release(cmpxchg64, __VA_ARGS__) #endif #ifndef cmpxchg64 #define cmpxchg64(...) \ __atomic_op_fence(cmpxchg64, __VA_ARGS__) #endif #endif /* cmpxchg64_relaxed */ /* xchg_relaxed */ #ifndef xchg_relaxed #define xchg_relaxed xchg #define xchg_acquire xchg #define xchg_release xchg #else /* xchg_relaxed */ #ifndef xchg_acquire #define xchg_acquire(...) __atomic_op_acquire(xchg, __VA_ARGS__) #endif #ifndef xchg_release #define xchg_release(...) __atomic_op_release(xchg, __VA_ARGS__) #endif #ifndef xchg #define xchg(...) __atomic_op_fence(xchg, __VA_ARGS__) #endif #endif /* xchg_relaxed */ /** * atomic_add_unless - add unless the number is already 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 @v was not already @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) { return __atomic_add_unless(v, a, u) != u; } /** * atomic_inc_not_zero - increment unless the number is zero * @v: pointer of type atomic_t * * Atomically increments @v by 1, so long as @v is non-zero. * Returns non-zero if @v was non-zero, and zero otherwise. */ #ifndef atomic_inc_not_zero #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) #endif #ifndef atomic_andnot static inline void atomic_andnot(int i, atomic_t *v) { atomic_and(~i, v); } #endif static inline __deprecated void atomic_clear_mask(unsigned int mask, atomic_t *v) { atomic_andnot(mask, v); } static inline __deprecated void atomic_set_mask(unsigned int mask, atomic_t *v) { atomic_or(mask, v); } /** * atomic_inc_not_zero_hint - increment if not null * @v: pointer of type atomic_t * @hint: probable value of the atomic before the increment * * This version of atomic_inc_not_zero() gives a hint of probable * value of the atomic. This helps processor to not read the memory * before doing the atomic read/modify/write cycle, lowering * number of bus transactions on some arches. * * Returns: 0 if increment was not done, 1 otherwise. */ #ifndef atomic_inc_not_zero_hint static inline int atomic_inc_not_zero_hint(atomic_t *v, int hint) { int val, c = hint; /* sanity test, should be removed by compiler if hint is a constant */ if (!hint) return atomic_inc_not_zero(v); do { val = atomic_cmpxchg(v, c, c + 1); if (val == c) return 1; c = val; } while (c); return 0; } #endif #ifndef atomic_inc_unless_negative static inline int atomic_inc_unless_negative(atomic_t *p) { int v, v1; for (v = 0; v >= 0; v = v1) { v1 = atomic_cmpxchg(p, v, v + 1); if (likely(v1 == v)) return 1; } return 0; } #endif #ifndef atomic_dec_unless_positive static inline int atomic_dec_unless_positive(atomic_t *p) { int v, v1; for (v = 0; v <= 0; v = v1) { v1 = atomic_cmpxchg(p, v, v - 1); if (likely(v1 == v)) return 1; } return 0; } #endif /* * atomic_dec_if_positive - decrement by 1 if old value positive * @v: pointer of type atomic_t * * The function returns the old value of *v minus 1, even if * the atomic variable, v, was not decremented. */ #ifndef atomic_dec_if_positive static inline int atomic_dec_if_positive(atomic_t *v) { int c, old, dec; c = atomic_read(v); for (;;) { dec = c - 1; if (unlikely(dec < 0)) break; old = atomic_cmpxchg((v), c, dec); if (likely(old == c)) break; c = old; } return dec; } #endif #ifdef CONFIG_GENERIC_ATOMIC64 #include #endif #ifndef atomic64_andnot static inline void atomic64_andnot(long long i, atomic64_t *v) { atomic64_and(~i, v); } #endif #include #endif /* _LINUX_ATOMIC_H */