1 /*-
2  * Copyright (c) 2010 Isilon Systems, Inc.
3  * Copyright (c) 2010 iX Systems, Inc.
4  * Copyright (c) 2010 Panasas, Inc.
5  * Copyright (c) 2013-2017 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	_ATOMIC_LONG_H_
32 #define	_ATOMIC_LONG_H_
33 
34 #include <linux/compiler.h>
35 #include <sys/types.h>
36 #include <machine/atomic.h>
37 
38 #define	ATOMIC_LONG_INIT(x)	{ .counter = (x) }
39 
40 typedef struct {
41 	volatile long counter;
42 } atomic_long_t;
43 
44 #define	atomic_long_add(i, v)		atomic_long_add_return((i), (v))
45 #define	atomic_long_sub(i, v)		atomic_long_add_return(-(i), (v))
46 #define	atomic_long_inc_return(v)	atomic_long_add_return(1, (v))
47 #define	atomic_long_inc_not_zero(v)	atomic_long_add_unless((v), 1, 0)
48 
49 static inline long
50 atomic_long_add_return(long i, atomic_long_t *v)
51 {
52 	return i + atomic_fetchadd_long(&v->counter, i);
53 }
54 
55 static inline void
56 atomic_long_set(atomic_long_t *v, long i)
57 {
58 	WRITE_ONCE(v->counter, i);
59 }
60 
61 static inline long
62 atomic_long_read(atomic_long_t *v)
63 {
64 	return READ_ONCE(v->counter);
65 }
66 
67 static inline long
68 atomic_long_inc(atomic_long_t *v)
69 {
70 	return atomic_fetchadd_long(&v->counter, 1) + 1;
71 }
72 
73 static inline long
74 atomic_long_dec(atomic_long_t *v)
75 {
76 	return atomic_fetchadd_long(&v->counter, -1) - 1;
77 }
78 
79 static inline long
80 atomic_long_xchg(atomic_long_t *v, long val)
81 {
82 	return atomic_swap_long(&v->counter, val);
83 }
84 
85 static inline long
86 atomic_long_cmpxchg(atomic_long_t *v, long old, long new)
87 {
88 	long ret = old;
89 
90 	for (;;) {
91 		if (atomic_fcmpset_long(&v->counter, &ret, new))
92 			break;
93 		if (ret != old)
94 			break;
95 	}
96 	return (ret);
97 }
98 
99 static inline int
100 atomic_long_add_unless(atomic_long_t *v, long a, long u)
101 {
102 	long c = atomic_long_read(v);
103 
104 	for (;;) {
105 		if (unlikely(c == u))
106 			break;
107 		if (likely(atomic_fcmpset_long(&v->counter, &c, c + a)))
108 			break;
109 	}
110 	return (c != u);
111 }
112 
113 static inline long
114 atomic_long_fetch_add_unless(atomic_long_t *v, long a, long u)
115 {
116 	long c = atomic_long_read(v);
117 
118 	for (;;) {
119 		if (unlikely(c == u))
120 			break;
121 		if (likely(atomic_fcmpset_long(&v->counter, &c, c + a)))
122 			break;
123 	}
124 	return (c);
125 }
126 
127 static inline long
128 atomic_long_dec_and_test(atomic_long_t *v)
129 {
130 	long i = atomic_long_add(-1, v);
131 	return i == 0 ;
132 }
133 
134 #endif	/* _ATOMIC_LONG_H_ */
135