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

/*
 * Generic C implementation of atomic counter operations
 * Originally implemented for MN10300.
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */
#ifndef __ASM_GENERIC_ATOMIC_H
#define __ASM_GENERIC_ATOMIC_H

#ifdef CONFIG_SMP
#error not SMP safe
#endif

/*
 * Atomic operations that C can't guarantee us.  Useful for
 * resource counting etc..
 */

#define ATOMIC_INIT(i)	{ (i) }

#ifdef __KERNEL__

/**
 * atomic_read - read atomic variable
 * @v: pointer of type atomic_t
 *
 * Atomically reads the value of @v.
 */
#define atomic_read(v)	(*(volatile int *)&(v)->counter)

/**
 * atomic_set - set atomic variable
 * @v: pointer of type atomic_t
 * @i: required value
 *
 * Atomically sets the value of @v to @i.
 */
#define atomic_set(v, i) (((v)->counter) = (i))

#include <asm/system.h>

/**
 * atomic_add_return - add integer to atomic variable
 * @i: integer value to add
 * @v: pointer of type atomic_t
 *
 * Atomically adds @i to @v and returns the result
 */
static inline int atomic_add_return(int i, atomic_t *v)
{
	unsigned long flags;
	int temp;

	local_irq_save(flags);
	temp = v->counter;
	temp += i;
	v->counter = temp;
	local_irq_restore(flags);

	return temp;
}

/**
 * atomic_sub_return - subtract integer from atomic variable
 * @i: integer value to subtract
 * @v: pointer of type atomic_t
 *
 * Atomically subtracts @i from @v and returns the result
 */
static inline int atomic_sub_return(int i, atomic_t *v)
{
	unsigned long flags;
	int temp;

	local_irq_save(flags);
	temp = v->counter;
	temp -= i;
	v->counter = temp;
	local_irq_restore(flags);

	return temp;
}

static inline int atomic_add_negative(int i, atomic_t *v)
{
	return atomic_add_return(i, v) < 0;
}

static inline void atomic_add(int i, atomic_t *v)
{
	atomic_add_return(i, v);
}

static inline void atomic_sub(int i, atomic_t *v)
{
	atomic_sub_return(i, v);
}

static inline void atomic_inc(atomic_t *v)
{
	atomic_add_return(1, v);
}

static inline void atomic_dec(atomic_t *v)
{
	atomic_sub_return(1, v);
}

#define atomic_dec_return(v)		atomic_sub_return(1, (v))
#define atomic_inc_return(v)		atomic_add_return(1, (v))

#define atomic_sub_and_test(i, v)	(atomic_sub_return((i), (v)) == 0)
#define atomic_dec_and_test(v)		(atomic_sub_return(1, (v)) == 0)
#define atomic_inc_and_test(v)		(atomic_add_return(1, (v)) == 0)

#define atomic_add_unless(v, a, u)				\
({								\
	int c, old;						\
	c = atomic_read(v);					\
	while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c) \
		c = old;					\
	c != (u);						\
})

#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)

static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
{
	unsigned long flags;

	mask = ~mask;
	local_irq_save(flags);
	*addr &= mask;
	local_irq_restore(flags);
}

#define atomic_xchg(ptr, v)		(xchg(&(ptr)->counter, (v)))
#define atomic_cmpxchg(v, old, new)	(cmpxchg(&((v)->counter), (old), (new)))

#define cmpxchg_local(ptr, o, n)				  	       \
	((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\
			(unsigned long)(n), sizeof(*(ptr))))

#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))

/* Assume that atomic operations are already serializing */
#define smp_mb__before_atomic_dec()	barrier()
#define smp_mb__after_atomic_dec()	barrier()
#define smp_mb__before_atomic_inc()	barrier()
#define smp_mb__after_atomic_inc()	barrier()

#include <asm-generic/atomic-long.h>

#endif /* __KERNEL__ */
#endif /* __ASM_GENERIC_ATOMIC_H */
Commit	Line	Data
3f7e212d AB	1	/*
	2	* Generic C implementation of atomic counter operations
	3	* Originally implemented for MN10300.
	4	*
	5	* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
	6	* Written by David Howells (dhowells@redhat.com)
	7	*
	8	* This program is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU General Public Licence
	10	* as published by the Free Software Foundation; either version
	11	* 2 of the Licence, or (at your option) any later version.
	12	*/
	13	#ifndef __ASM_GENERIC_ATOMIC_H
	14	#define __ASM_GENERIC_ATOMIC_H
	15
	16	#ifdef CONFIG_SMP
	17	#error not SMP safe
	18	#endif
	19
	20	/*
	21	* Atomic operations that C can't guarantee us. Useful for
	22	* resource counting etc..
	23	*/
	24
	25	#define ATOMIC_INIT(i) { (i) }
	26
	27	#ifdef __KERNEL__
	28
	29	/**
	30	* atomic_read - read atomic variable
	31	* @v: pointer of type atomic_t
	32	*
37682177	33	* Atomically reads the value of @v.
3f7e212d	34	*/
f3d46f9d	35	#define atomic_read(v) ((volatile int )&(v)->counter)
3f7e212d AB	36
	37	/**
	38	* atomic_set - set atomic variable
	39	* @v: pointer of type atomic_t
	40	* @i: required value
	41	*
37682177	42	* Atomically sets the value of @v to @i.
3f7e212d AB	43	*/
	44	#define atomic_set(v, i) (((v)->counter) = (i))
	45
	46	#include <asm/system.h>
	47
	48	/**
	49	* atomic_add_return - add integer to atomic variable
	50	* @i: integer value to add
	51	* @v: pointer of type atomic_t
	52	*
	53	* Atomically adds @i to @v and returns the result
3f7e212d AB	54	*/
	55	static inline int atomic_add_return(int i, atomic_t *v)
	56	{
	57	unsigned long flags;
	58	int temp;
	59
	60	local_irq_save(flags);
	61	temp = v->counter;
	62	temp += i;
	63	v->counter = temp;
	64	local_irq_restore(flags);
	65
	66	return temp;
	67	}
	68
	69	/**
	70	* atomic_sub_return - subtract integer from atomic variable
	71	* @i: integer value to subtract
	72	* @v: pointer of type atomic_t
	73	*
	74	* Atomically subtracts @i from @v and returns the result
3f7e212d AB	75	*/
	76	static inline int atomic_sub_return(int i, atomic_t *v)
	77	{
	78	unsigned long flags;
	79	int temp;
	80
	81	local_irq_save(flags);
	82	temp = v->counter;
	83	temp -= i;
	84	v->counter = temp;
	85	local_irq_restore(flags);
	86
	87	return temp;
	88	}
	89
	90	static inline int atomic_add_negative(int i, atomic_t *v)
	91	{
	92	return atomic_add_return(i, v) < 0;
	93	}
	94
	95	static inline void atomic_add(int i, atomic_t *v)
	96	{
	97	atomic_add_return(i, v);
	98	}
	99
	100	static inline void atomic_sub(int i, atomic_t *v)
	101	{
	102	atomic_sub_return(i, v);
	103	}
	104
	105	static inline void atomic_inc(atomic_t *v)
	106	{
	107	atomic_add_return(1, v);
	108	}
	109
	110	static inline void atomic_dec(atomic_t *v)
	111	{
	112	atomic_sub_return(1, v);
	113	}
	114
	115	#define atomic_dec_return(v) atomic_sub_return(1, (v))
	116	#define atomic_inc_return(v) atomic_add_return(1, (v))
	117
	118	#define atomic_sub_and_test(i, v) (atomic_sub_return((i), (v)) == 0)
	119	#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
	120	#define atomic_inc_and_test(v) (atomic_add_return(1, (v)) == 0)
	121
	122	#define atomic_add_unless(v, a, u) \
	123	({ \
	124	int c, old; \
	125	c = atomic_read(v); \
	126	while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c) \
	127	c = old; \
	128	c != (u); \
	129	})
	130
	131	#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
	132
	133	static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
	134	{
	135	unsigned long flags;
	136
	137	mask = ~mask;
	138	local_irq_save(flags);
139	*addr &= mask;
140	local_irq_restore(flags);
141	}
142
143	#define atomic_xchg(ptr, v) (xchg(&(ptr)->counter, (v)))
144	#define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new)))
145
146	#define cmpxchg_local(ptr, o, n) \
147	((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\
148	(unsigned long)(n), sizeof(*(ptr))))
149
150	#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
151
152	/* Assume that atomic operations are already serializing */
153	#define smp_mb__before_atomic_dec() barrier()
154	#define smp_mb__after_atomic_dec() barrier()
155	#define smp_mb__before_atomic_inc() barrier()
156	#define smp_mb__after_atomic_inc() barrier()
157
158	#include <asm-generic/atomic-long.h>
159
160	#endif /* __KERNEL__ */
161	#endif /* __ASM_GENERIC_ATOMIC_H */