1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
|
/*-
* Copyright (c) 2010 Isilon Systems, Inc.
* Copyright (c) 2010 iX Systems, Inc.
* Copyright (c) 2010 Panasas, Inc.
* Copyright (c) 2013-2015 Mellanox Technologies, Ltd.
* Copyright (c) 2013 François Tigeot
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice unmodified, this list of conditions, and the following
* disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _LINUX_KREF_H_
#define _LINUX_KREF_H_
#include <sys/types.h>
#include <sys/refcount.h>
#include <linux/compiler.h>
#include <linux/kernel.h>
#include <linux/mutex.h>
#include <linux/refcount.h>
#include <asm/atomic.h>
struct kref {
atomic_t refcount;
};
static inline void
kref_init(struct kref *kref)
{
refcount_init(&kref->refcount.counter, 1);
}
static inline unsigned int
kref_read(const struct kref *kref)
{
return (atomic_read(&kref->refcount));
}
static inline void
kref_get(struct kref *kref)
{
refcount_acquire(&kref->refcount.counter);
}
static inline int
kref_put(struct kref *kref, void (*rel)(struct kref *kref))
{
if (refcount_release(&kref->refcount.counter)) {
rel(kref);
return 1;
}
return 0;
}
static inline int
kref_put_lock(struct kref *kref, void (*rel)(struct kref *kref),
spinlock_t *lock)
{
if (refcount_release(&kref->refcount.counter)) {
spin_lock(lock);
rel(kref);
return (1);
}
return (0);
}
static inline int
kref_sub(struct kref *kref, unsigned int count,
void (*rel)(struct kref *kref))
{
while (count--) {
if (refcount_release(&kref->refcount.counter)) {
rel(kref);
return 1;
}
}
return 0;
}
static inline int __must_check
kref_get_unless_zero(struct kref *kref)
{
return atomic_add_unless(&kref->refcount, 1, 0);
}
static inline int kref_put_mutex(struct kref *kref,
void (*release)(struct kref *kref), struct mutex *lock)
{
WARN_ON(release == NULL);
if (unlikely(!atomic_add_unless(&kref->refcount, -1, 1))) {
mutex_lock(lock);
if (unlikely(!atomic_dec_and_test(&kref->refcount))) {
mutex_unlock(lock);
return 0;
}
release(kref);
return 1;
}
return 0;
}
#endif /* _LINUX_KREF_H_ */
|
