Commit | Line | Data |
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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 */ |