[GitHub/mt8127/android_kernel_alcatel_ttab.git] / include / linux / atomic.h

/* 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

/*
 * atomic_dec_if_positive - decrement by 1 if old value positive
 * @v: pointer of type atomic_t
 *
 * The function returns the old value of *v minus 1, even if
 * the atomic variable, v, was not decremented.
 */
#ifndef atomic_dec_if_positive
static inline int atomic_dec_if_positive(atomic_t *v)
{
	int c, old, dec;
	c = atomic_read(v);
	for (;;) {
		dec = c - 1;
		if (unlikely(dec < 0))
			break;
		old = atomic_cmpxchg((v), c, dec);
		if (likely(old == c))
			break;
		c = old;
	}
	return dec;
}
#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 */
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 */