2 * Copyright (c) 2010 Isilon Systems, Inc.
3 * Copyright (c) 2010 iX Systems, Inc.
4 * Copyright (c) 2010 Panasas, Inc.
5 * Copyright (c) 2013-2020 François Tigeot <ftigeot@wolfpond.org>
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice unmodified, this list of conditions, and the following
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.
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.
30 #ifndef _LINUX_KREF_H_
31 #define _LINUX_KREF_H_
33 #include <linux/spinlock.h>
34 #include <linux/refcount.h>
41 kref_init(struct kref *kref)
43 atomic_set(&kref->refcount.refs, 1);
46 static inline unsigned int
47 kref_read(const struct kref *kref)
49 return atomic_read(&kref->refcount.refs);
53 kref_get(struct kref *kref)
55 refcount_inc(&kref->refcount);
59 kref_put(struct kref *kref, void (*release)(struct kref *kref))
61 if (atomic_dec_and_test(&kref->refcount.refs)) {
71 kref_sub(struct kref *kref, unsigned int count,
72 void (*rel)(struct kref *kref))
74 if (refcount_release_n(&kref->refcount.counter, count)) {
83 * kref_get_unless_zero: Increment refcount for object unless it is zero.
85 static inline int __must_check kref_get_unless_zero(struct kref *kref)
87 return atomic_add_unless(&kref->refcount.refs, 1, 0);
90 static inline int kref_put_mutex(struct kref *kref,
91 void (*release)(struct kref *kref),
94 if (!atomic_add_unless(&kref->refcount.refs, -1, 1)) {
96 if (likely(atomic_dec_and_test(&kref->refcount.refs))) {
107 #endif /* _LINUX_KREF_H_ */