/* Atomic operations usable in machine independent code */ #ifndef _LINUX_ATOMIC_H #define _LINUX_ATOMIC_H #include /** * 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. */ #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) /** * 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 #ifndef CONFIG_ARCH_HAS_ATOMIC_OR static inline void atomic_or(int i, atomic_t *v) { int old; int new; do { old = atomic_read(v); new = old | i; } while (atomic_cmpxchg(v, old, new) != old); } #endif /* #ifndef CONFIG_ARCH_HAS_ATOMIC_OR */ #include #ifdef CONFIG_GENERIC_ATOMIC64 #include #endif #endif /* _LINUX_ATOMIC_H */