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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 | ||
37 | #endif /* _LINUX_ATOMIC_H */ |