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 #if defined(__i386__) || defined(__amd64__) || defined(__aarch64__)
83 	return atomic_swap_long(&v->counter, val);
84 #else
85 	long ret = atomic_long_read(v);
86 
87 	while (!atomic_fcmpset_long(&v->counter, &ret, val))
88 		;
89 	return (ret);
90 #endif
91 }
92 
93 static inline long
94 atomic_long_cmpxchg(atomic_long_t *v, long old, long new)
95 {
96 	long ret = old;
97 
98 	for (;;) {
99 		if (atomic_fcmpset_long(&v->counter, &ret, new))
100 			break;
101 		if (ret != old)
102 			break;
103 	}
104 	return (ret);
105 }
106 
107 static inline int
108 atomic_long_add_unless(atomic_long_t *v, long a, long u)
109 {
110 	long c = atomic_long_read(v);
111 
112 	for (;;) {
113 		if (unlikely(c == u))
114 			break;
115 		if (likely(atomic_fcmpset_long(&v->counter, &c, c + a)))
116 			break;
117 	}
118 	return (c != u);
119 }
120 
121 static inline long
122 atomic_long_dec_and_test(atomic_long_t *v)
123 {
124 	long i = atomic_long_add(-1, v);
125 	return i == 0 ;
126 }
127 
128 #endif	/* _ATOMIC_LONG_H_ */
129