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Eric Dumazet3f9d35b2010-11-11 14:05:08 -08001#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
18static 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 */