[net-next-2.6.git] / include / linux / atomic.h

#ifndef _LINUX_ATOMIC_H
#define _LINUX_ATOMIC_H
#include <asm/atomic.h>

/**
 * 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

#endif /* _LINUX_ATOMIC_H */
Commit	Line	Data
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
	37	#endif /* _LINUX_ATOMIC_H */