1 /*-
2 * Copyright (c) 2010 Isilon Systems, Inc.
3 * Copyright (c) 2010 iX Systems, Inc.
4 * Copyright (c) 2010 Panasas, Inc.
5 * Copyright (c) 2013-2015 Mellanox Technologies, Ltd.
6 * Copyright (c) 2013 François Tigeot
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice unmodified, this list of conditions, and the following
14 * disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 *
30 * $FreeBSD$
31 */
32 #ifndef _LINUXKPI_LINUX_KREF_H_
33 #define _LINUXKPI_LINUX_KREF_H_
34
35 #include <sys/types.h>
36 #include <sys/refcount.h>
37
38 #include <linux/compiler.h>
39 #include <linux/kernel.h>
40 #include <linux/mutex.h>
41 #include <linux/refcount.h>
42
43 #include <asm/atomic.h>
44
45 struct kref {
46 atomic_t refcount;
47 };
48
49 static inline void
kref_init(struct kref * kref)50 kref_init(struct kref *kref)
51 {
52
53 refcount_init(&kref->refcount.counter, 1);
54 }
55
56 static inline unsigned int
kref_read(const struct kref * kref)57 kref_read(const struct kref *kref)
58 {
59
60 return (atomic_read(&kref->refcount));
61 }
62
63 static inline void
kref_get(struct kref * kref)64 kref_get(struct kref *kref)
65 {
66
67 refcount_acquire(&kref->refcount.counter);
68 }
69
70 static inline int
kref_put(struct kref * kref,void (* rel)(struct kref * kref))71 kref_put(struct kref *kref, void (*rel)(struct kref *kref))
72 {
73
74 if (refcount_release(&kref->refcount.counter)) {
75 rel(kref);
76 return 1;
77 }
78 return 0;
79 }
80
81 static inline int
kref_put_lock(struct kref * kref,void (* rel)(struct kref * kref),spinlock_t * lock)82 kref_put_lock(struct kref *kref, void (*rel)(struct kref *kref),
83 spinlock_t *lock)
84 {
85
86 if (refcount_release(&kref->refcount.counter)) {
87 spin_lock(lock);
88 rel(kref);
89 return (1);
90 }
91 return (0);
92 }
93
94 static inline int
kref_sub(struct kref * kref,unsigned int count,void (* rel)(struct kref * kref))95 kref_sub(struct kref *kref, unsigned int count,
96 void (*rel)(struct kref *kref))
97 {
98
99 while (count--) {
100 if (refcount_release(&kref->refcount.counter)) {
101 rel(kref);
102 return 1;
103 }
104 }
105 return 0;
106 }
107
108 static inline int __must_check
kref_get_unless_zero(struct kref * kref)109 kref_get_unless_zero(struct kref *kref)
110 {
111
112 return atomic_add_unless(&kref->refcount, 1, 0);
113 }
114
kref_put_mutex(struct kref * kref,void (* release)(struct kref * kref),struct mutex * lock)115 static inline int kref_put_mutex(struct kref *kref,
116 void (*release)(struct kref *kref), struct mutex *lock)
117 {
118 WARN_ON(release == NULL);
119 if (unlikely(!atomic_add_unless(&kref->refcount, -1, 1))) {
120 mutex_lock(lock);
121 if (unlikely(!atomic_dec_and_test(&kref->refcount))) {
122 mutex_unlock(lock);
123 return 0;
124 }
125 release(kref);
126 return 1;
127 }
128 return 0;
129 }
130
131 #endif /* _LINUXKPI_LINUX_KREF_H_ */
132