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 | */ | |
b1ada601 | 27 | #ifndef atomic_inc_not_zero |
60063497 | 28 | #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0) |
b1ada601 | 29 | #endif |
60063497 | 30 | |
3f9d35b9 ED |
31 | /** |
32 | * atomic_inc_not_zero_hint - increment if not null | |
33 | * @v: pointer of type atomic_t | |
34 | * @hint: probable value of the atomic before the increment | |
35 | * | |
36 | * This version of atomic_inc_not_zero() gives a hint of probable | |
37 | * value of the atomic. This helps processor to not read the memory | |
38 | * before doing the atomic read/modify/write cycle, lowering | |
39 | * number of bus transactions on some arches. | |
40 | * | |
41 | * Returns: 0 if increment was not done, 1 otherwise. | |
42 | */ | |
43 | #ifndef atomic_inc_not_zero_hint | |
44 | static inline int atomic_inc_not_zero_hint(atomic_t *v, int hint) | |
45 | { | |
46 | int val, c = hint; | |
47 | ||
48 | /* sanity test, should be removed by compiler if hint is a constant */ | |
49 | if (!hint) | |
50 | return atomic_inc_not_zero(v); | |
51 | ||
52 | do { | |
53 | val = atomic_cmpxchg(v, c, c + 1); | |
54 | if (val == c) | |
55 | return 1; | |
56 | c = val; | |
57 | } while (c); | |
58 | ||
59 | return 0; | |
60 | } | |
61 | #endif | |
62 | ||
07b8ce1e AV |
63 | #ifndef atomic_inc_unless_negative |
64 | static inline int atomic_inc_unless_negative(atomic_t *p) | |
65 | { | |
66 | int v, v1; | |
67 | for (v = 0; v >= 0; v = v1) { | |
68 | v1 = atomic_cmpxchg(p, v, v + 1); | |
69 | if (likely(v1 == v)) | |
70 | return 1; | |
71 | } | |
72 | return 0; | |
73 | } | |
74 | #endif | |
75 | ||
76 | #ifndef atomic_dec_unless_positive | |
77 | static inline int atomic_dec_unless_positive(atomic_t *p) | |
78 | { | |
79 | int v, v1; | |
80 | for (v = 0; v <= 0; v = v1) { | |
81 | v1 = atomic_cmpxchg(p, v, v - 1); | |
82 | if (likely(v1 == v)) | |
83 | return 1; | |
84 | } | |
85 | return 0; | |
86 | } | |
87 | #endif | |
88 | ||
e79bee24 SL |
89 | /* |
90 | * atomic_dec_if_positive - decrement by 1 if old value positive | |
91 | * @v: pointer of type atomic_t | |
92 | * | |
93 | * The function returns the old value of *v minus 1, even if | |
94 | * the atomic variable, v, was not decremented. | |
95 | */ | |
96 | #ifndef atomic_dec_if_positive | |
97 | static inline int atomic_dec_if_positive(atomic_t *v) | |
98 | { | |
99 | int c, old, dec; | |
100 | c = atomic_read(v); | |
101 | for (;;) { | |
102 | dec = c - 1; | |
103 | if (unlikely(dec < 0)) | |
104 | break; | |
105 | old = atomic_cmpxchg((v), c, dec); | |
106 | if (likely(old == c)) | |
107 | break; | |
108 | c = old; | |
109 | } | |
110 | return dec; | |
111 | } | |
112 | #endif | |
113 | ||
55c2945a PM |
114 | #ifndef CONFIG_ARCH_HAS_ATOMIC_OR |
115 | static inline void atomic_or(int i, atomic_t *v) | |
116 | { | |
117 | int old; | |
118 | int new; | |
119 | ||
120 | do { | |
121 | old = atomic_read(v); | |
122 | new = old | i; | |
123 | } while (atomic_cmpxchg(v, old, new) != old); | |
124 | } | |
125 | #endif /* #ifndef CONFIG_ARCH_HAS_ATOMIC_OR */ | |
126 | ||
7847777a AS |
127 | #include <asm-generic/atomic-long.h> |
128 | #ifdef CONFIG_GENERIC_ATOMIC64 | |
129 | #include <asm-generic/atomic64.h> | |
130 | #endif | |
3f9d35b9 | 131 | #endif /* _LINUX_ATOMIC_H */ |