atomic.h revision 259065 
1/*-
2 * Copyright (c) 2010 Isilon Systems, Inc.
3 * Copyright (c) 2010 iX Systems, Inc.
4 * Copyright (c) 2010 Panasas, Inc.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice unmodified, this list of conditions, and the following
12 *    disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#ifndef	_ASM_ATOMIC_H_
30#define	_ASM_ATOMIC_H_
31
32#include <sys/cdefs.h>
33#include <sys/types.h>
34#include <machine/atomic.h>
35#include <asm/atomic-long.h>
36
37typedef struct {
38	volatile u_int counter;
39} atomic_t;
40
41#define	atomic_add(i, v)		atomic_add_return((i), (v))
42#define	atomic_sub(i, v)		atomic_sub_return((i), (v))
43#define	atomic_inc_return(v)		atomic_add_return(1, (v))
44#define	atomic_add_negative(i, v)	(atomic_add_return((i), (v)) < 0)
45#define	atomic_sub_and_test(i, v)	(atomic_sub_return((i), (v)) == 0)
46#define	atomic_dec_and_test(v)		(atomic_sub_return(1, (v)) == 0)
47#define	atomic_inc_and_test(v)		(atomic_add_return(1, (v)) == 0)
48#define atomic_dec_return(v)             atomic_sub_return(1, (v))
49
50static inline int
51atomic_add_return(int i, atomic_t *v)
52{
53	return i + atomic_fetchadd_int(&v->counter, i);
54}
55
56static inline int
57atomic_sub_return(int i, atomic_t *v)
58{
59	return atomic_fetchadd_int(&v->counter, -i) - i;
60}
61
62static inline void
63atomic_set(atomic_t *v, int i)
64{
65	atomic_store_rel_int(&v->counter, i);
66}
67
68static inline int
69atomic_read(atomic_t *v)
70{
71	return atomic_load_acq_int(&v->counter);
72}
73
74static inline int
75atomic_inc(atomic_t *v)
76{
77	return atomic_fetchadd_int(&v->counter, 1) + 1;
78}
79
80static inline int
81atomic_dec(atomic_t *v)
82{
83	return atomic_fetchadd_int(&v->counter, -1) - 1;
84}
85
86static inline int atomic_add_unless(atomic_t *v, int a, int u)
87{
88        int c, old;
89        c = atomic_read(v);
90        for (;;) {
91                if (unlikely(c == (u)))
92                        break;
93                // old = atomic_cmpxchg((v), c, c + (a)); /*Linux*/
94                old = atomic_cmpset_int(&v->counter, c, c + (a));
95                if (likely(old == c))
96                        break;
97                c = old;
98        }
99        return c != (u);
100}
101
102#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
103
104
105
106
107#endif	/* _ASM_ATOMIC_H_ */
108