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3f9d35b9 ED |
1 | #ifndef _LINUX_ATOMIC_H |
2 | #define _LINUX_ATOMIC_H | |
3 | #include <asm/atomic.h> | |
4 | ||
5 | /** | |
6 | * atomic_inc_not_zero_hint - increment if not null | |
7 | * @v: pointer of type atomic_t | |
8 | * @hint: probable value of the atomic before the increment | |
9 | * | |
10 | * This version of atomic_inc_not_zero() gives a hint of probable | |
11 | * value of the atomic. This helps processor to not read the memory | |
12 | * before doing the atomic read/modify/write cycle, lowering | |
13 | * number of bus transactions on some arches. | |
14 | * | |
15 | * Returns: 0 if increment was not done, 1 otherwise. | |
16 | */ | |
17 | #ifndef atomic_inc_not_zero_hint | |
18 | static inline int atomic_inc_not_zero_hint(atomic_t *v, int hint) | |
19 | { | |
20 | int val, c = hint; | |
21 | ||
22 | /* sanity test, should be removed by compiler if hint is a constant */ | |
23 | if (!hint) | |
24 | return atomic_inc_not_zero(v); | |
25 | ||
26 | do { | |
27 | val = atomic_cmpxchg(v, c, c + 1); | |
28 | if (val == c) | |
29 | return 1; | |
30 | c = val; | |
31 | } while (c); | |
32 | ||
33 | return 0; | |
34 | } | |
35 | #endif | |
36 | ||
07b8ce1e AV |
37 | #ifndef atomic_inc_unless_negative |
38 | static inline int atomic_inc_unless_negative(atomic_t *p) | |
39 | { | |
40 | int v, v1; | |
41 | for (v = 0; v >= 0; v = v1) { | |
42 | v1 = atomic_cmpxchg(p, v, v + 1); | |
43 | if (likely(v1 == v)) | |
44 | return 1; | |
45 | } | |
46 | return 0; | |
47 | } | |
48 | #endif | |
49 | ||
50 | #ifndef atomic_dec_unless_positive | |
51 | static inline int atomic_dec_unless_positive(atomic_t *p) | |
52 | { | |
53 | int v, v1; | |
54 | for (v = 0; v <= 0; v = v1) { | |
55 | v1 = atomic_cmpxchg(p, v, v - 1); | |
56 | if (likely(v1 == v)) | |
57 | return 1; | |
58 | } | |
59 | return 0; | |
60 | } | |
61 | #endif | |
62 | ||
55c2945a PM |
63 | #ifndef CONFIG_ARCH_HAS_ATOMIC_OR |
64 | static inline void atomic_or(int i, atomic_t *v) | |
65 | { | |
66 | int old; | |
67 | int new; | |
68 | ||
69 | do { | |
70 | old = atomic_read(v); | |
71 | new = old | i; | |
72 | } while (atomic_cmpxchg(v, old, new) != old); | |
73 | } | |
74 | #endif /* #ifndef CONFIG_ARCH_HAS_ATOMIC_OR */ | |
75 | ||
3f9d35b9 | 76 | #endif /* _LINUX_ATOMIC_H */ |