projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| acac43e2 | 1 | /* Atomic operations usable in machine independent code */ |
| 3f9d35b9 ED |
2 | #ifndef _LINUX_ATOMIC_H |
| 3 | #define _LINUX_ATOMIC_H | |
| 4 | #include <asm/atomic.h> | |
| 5 | ||
| f24219b4 AS |
6 | /** |
| 7 | * atomic_add_unless - add unless the number is already a given value | |
| 8 | * @v: pointer of type atomic_t | |
| 9 | * @a: the amount to add to v... | |
| 10 | * @u: ...unless v is equal to u. | |
| 11 | * | |
| 12 | * Atomically adds @a to @v, so long as @v was not already @u. | |
| 13 | * Returns non-zero if @v was not @u, and zero otherwise. | |
| 14 | */ | |
| 15 | static inline int atomic_add_unless(atomic_t *v, int a, int u) | |
| 16 | { | |
| 17 | return __atomic_add_unless(v, a, u) != u; | |
| 18 | } | |
| 19 | ||
| 60063497 AS |
20 | /** |
| 21 | * atomic_inc_not_zero - increment unless the number is zero | |
| 22 | * @v: pointer of type atomic_t | |
| 23 | * | |
| 24 | * Atomically increments @v by 1, so long as @v is non-zero. | |
| 25 | * Returns non-zero if @v was non-zero, and zero otherwise. | |
| 26 | */ | |
| 27 | #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) | |
| 28 | ||
| 3f9d35b9 ED |
29 | /** |
| 30 | * atomic_inc_not_zero_hint - increment if not null | |
| 31 | * @v: pointer of type atomic_t | |
| 32 | * @hint: probable value of the atomic before the increment | |
| 33 | * | |
| 34 | * This version of atomic_inc_not_zero() gives a hint of probable | |
| 35 | * value of the atomic. This helps processor to not read the memory | |
| 36 | * before doing the atomic read/modify/write cycle, lowering | |
| 37 | * number of bus transactions on some arches. | |
| 38 | * | |
| 39 | * Returns: 0 if increment was not done, 1 otherwise. | |
| 40 | */ | |
| 41 | #ifndef atomic_inc_not_zero_hint | |
| 42 | static inline int atomic_inc_not_zero_hint(atomic_t *v, int hint) | |
| 43 | { | |
| 44 | int val, c = hint; | |
| 45 | ||
| 46 | /* sanity test, should be removed by compiler if hint is a constant */ | |
| 47 | if (!hint) | |
| 48 | return atomic_inc_not_zero(v); | |
| 49 | ||
| 50 | do { | |
| 51 | val = atomic_cmpxchg(v, c, c + 1); | |
| 52 | if (val == c) | |
| 53 | return 1; | |
| 54 | c = val; | |
| 55 | } while (c); | |
| 56 | ||
| 57 | return 0; | |
| 58 | } | |
| 59 | #endif | |
| 60 | ||
| 07b8ce1e AV |
61 | #ifndef atomic_inc_unless_negative |
| 62 | static inline int atomic_inc_unless_negative(atomic_t *p) | |
| 63 | { | |
| 64 | int v, v1; | |
| 65 | for (v = 0; v >= 0; v = v1) { | |
| 66 | v1 = atomic_cmpxchg(p, v, v + 1); | |
| 67 | if (likely(v1 == v)) | |
| 68 | return 1; | |
| 69 | } | |
| 70 | return 0; | |
| 71 | } | |
| 72 | #endif | |
| 73 | ||
| 74 | #ifndef atomic_dec_unless_positive | |
| 75 | static inline int atomic_dec_unless_positive(atomic_t *p) | |
| 76 | { | |
| 77 | int v, v1; | |
| 78 | for (v = 0; v <= 0; v = v1) { | |
| 79 | v1 = atomic_cmpxchg(p, v, v - 1); | |
| 80 | if (likely(v1 == v)) | |
| 81 | return 1; | |
| 82 | } | |
| 83 | return 0; | |
| 84 | } | |
| 85 | #endif | |
| 86 | ||
| 55c2945a PM |
87 | #ifndef CONFIG_ARCH_HAS_ATOMIC_OR |
| 88 | static inline void atomic_or(int i, atomic_t *v) | |
| 89 | { | |
| 90 | int old; | |
| 91 | int new; | |
| 92 | ||
| 93 | do { | |
| 94 | old = atomic_read(v); | |
| 95 | new = old | i; | |
| 96 | } while (atomic_cmpxchg(v, old, new) != old); | |
| 97 | } | |
| 98 | #endif /* #ifndef CONFIG_ARCH_HAS_ATOMIC_OR */ | |
| 99 | ||
| 7847777a AS |
100 | #include <asm-generic/atomic-long.h> |
| 101 | #ifdef CONFIG_GENERIC_ATOMIC64 | |
| 102 | #include <asm-generic/atomic64.h> | |
| 103 | #endif | |
| 3f9d35b9 | 104 | #endif /* _LINUX_ATOMIC_H */ |