1 /*-
2 * Copyright (c) 2010 Isilon Systems, Inc.
3 * Copyright (c) 2010 iX Systems, Inc.
4 * Copyright (c) 2010 Panasas, Inc.
5 * Copyright (c) 2013, 2014 Mellanox Technologies, Ltd.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice unmodified, this list of conditions, and the following
13 * disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 *
29 * $FreeBSD$
30 */
31 #ifndef _ASM_ATOMIC_H_
32 #define _ASM_ATOMIC_H_
33
34 #include <sys/cdefs.h>
35 #include <sys/types.h>
36 #include <machine/atomic.h>
37
38 typedef struct {
39 volatile u_int counter;
40 } atomic_t;
41
42 #define atomic_add(i, v) atomic_add_return((i), (v))
43 #define atomic_sub(i, v) atomic_sub_return((i), (v))
44 #define atomic_inc_return(v) atomic_add_return(1, (v))
45 #define atomic_add_negative(i, v) (atomic_add_return((i), (v)) < 0)
46 #define atomic_sub_and_test(i, v) (atomic_sub_return((i), (v)) == 0)
47 #define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
48 #define atomic_inc_and_test(v) (atomic_add_return(1, (v)) == 0)
49 #define atomic_dec_return(v) atomic_sub_return(1, (v))
50
51 static inline int
atomic_add_return(int i,atomic_t * v)52 atomic_add_return(int i, atomic_t *v)
53 {
54 return i + atomic_fetchadd_int(&v->counter, i);
55 }
56
57 static inline int
atomic_sub_return(int i,atomic_t * v)58 atomic_sub_return(int i, atomic_t *v)
59 {
60 return atomic_fetchadd_int(&v->counter, -i) - i;
61 }
62
63 static inline void
atomic_set(atomic_t * v,int i)64 atomic_set(atomic_t *v, int i)
65 {
66 atomic_store_rel_int(&v->counter, i);
67 }
68
69 static inline int
atomic_read(atomic_t * v)70 atomic_read(atomic_t *v)
71 {
72 return atomic_load_acq_int(&v->counter);
73 }
74
75 static inline int
atomic_inc(atomic_t * v)76 atomic_inc(atomic_t *v)
77 {
78 return atomic_fetchadd_int(&v->counter, 1) + 1;
79 }
80
81 static inline int
atomic_dec(atomic_t * v)82 atomic_dec(atomic_t *v)
83 {
84 return atomic_fetchadd_int(&v->counter, -1) - 1;
85 }
86
atomic_add_unless(atomic_t * v,int a,int u)87 static inline int atomic_add_unless(atomic_t *v, int a, int u)
88 {
89 int c, old;
90 c = atomic_read(v);
91 for (;;) {
92 if (unlikely(c == (u)))
93 break;
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