Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 | /* Atomic operations usable in machine independent code */
#ifndef _LINUX_ATOMIC_H
#define _LINUX_ATOMIC_H
#include <asm/atomic.h>
/**
* atomic_add_unless - add unless the number is already a given value
* @v: pointer of type atomic_t
* @a: the amount to add to v...
* @u: ...unless v is equal to u.
*
* Atomically adds @a to @v, so long as @v was not already @u.
* Returns non-zero if @v was not @u, and zero otherwise.
*/
static inline int atomic_add_unless(atomic_t *v, int a, int u)
{
return __atomic_add_unless(v, a, u) != u;
}
/**
* atomic_inc_not_zero - increment unless the number is zero
* @v: pointer of type atomic_t
*
* Atomically increments @v by 1, so long as @v is non-zero.
* Returns non-zero if @v was non-zero, and zero otherwise.
*/
#ifndef atomic_inc_not_zero
#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
#endif
/**
* atomic_inc_not_zero_hint - increment if not null
* @v: pointer of type atomic_t
* @hint: probable value of the atomic before the increment
*
* This version of atomic_inc_not_zero() gives a hint of probable
* value of the atomic. This helps processor to not read the memory
* before doing the atomic read/modify/write cycle, lowering
* number of bus transactions on some arches.
*
* Returns: 0 if increment was not done, 1 otherwise.
*/
#ifndef atomic_inc_not_zero_hint
static inline int atomic_inc_not_zero_hint(atomic_t *v, int hint)
{
int val, c = hint;
/* sanity test, should be removed by compiler if hint is a constant */
if (!hint)
return atomic_inc_not_zero(v);
do {
val = atomic_cmpxchg(v, c, c + 1);
if (val == c)
return 1;
c = val;
} while (c);
return 0;
}
#endif
#ifndef atomic_inc_unless_negative
static inline int atomic_inc_unless_negative(atomic_t *p)
{
int v, v1;
for (v = 0; v >= 0; v = v1) {
v1 = atomic_cmpxchg(p, v, v + 1);
if (likely(v1 == v))
return 1;
}
return 0;
}
#endif
#ifndef atomic_dec_unless_positive
static inline int atomic_dec_unless_positive(atomic_t *p)
{
int v, v1;
for (v = 0; v <= 0; v = v1) {
v1 = atomic_cmpxchg(p, v, v - 1);
if (likely(v1 == v))
return 1;
}
return 0;
}
#endif
#ifndef CONFIG_ARCH_HAS_ATOMIC_OR
static inline void atomic_or(int i, atomic_t *v)
{
int old;
int new;
do {
old = atomic_read(v);
new = old | i;
} while (atomic_cmpxchg(v, old, new) != old);
}
#endif /* #ifndef CONFIG_ARCH_HAS_ATOMIC_OR */
#include <asm-generic/atomic-long.h>
#ifdef CONFIG_GENERIC_ATOMIC64
#include <asm-generic/atomic64.h>
#endif
#endif /* _LINUX_ATOMIC_H */
|