1 /*-
2  * Copyright (c) 2020 The FreeBSD Foundation
3  *
4  * This software was developed by Emmanuel Vadot under sponsorship
5  * from the FreeBSD Foundation.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  * $FreeBSD$
29  */
30 
31 #ifndef _LINUX_REFCOUNT_H
32 #define _LINUX_REFCOUNT_H
33 
34 #include <linux/atomic.h>
35 
36 struct refcount_linux {
37 	atomic_t value;
38 };
39 typedef struct refcount_linux refcount_t;
40 
41 static inline void
42 refcount_set(refcount_t *ref, unsigned int i)
43 {
44 	atomic_set(&ref->value, i);
45 }
46 
47 static inline void
48 refcount_inc(refcount_t *ref)
49 {
50 	atomic_inc(&ref->value);
51 }
52 
53 static inline bool
54 refcount_inc_not_zero(refcount_t *ref)
55 {
56 	return (atomic_inc_not_zero(&ref->value));
57 }
58 
59 static inline void
60 refcount_dec(refcount_t *ref)
61 {
62 	atomic_dec(&ref->value);
63 }
64 
65 static inline unsigned int
66 refcount_read(refcount_t *ref)
67 {
68 	return atomic_read(&ref->value);
69 }
70 
71 static inline bool
72 refcount_dec_and_lock_irqsave(refcount_t *ref, spinlock_t *lock,
73     unsigned long *flags)
74 {
75 	if (atomic_dec_and_test(&ref->value) == true) {
76 		spin_lock_irqsave(lock, flags);
77 		return (true);
78 	}
79 	return (false);
80 }
81 
82 #endif /* __LINUX_REFCOUNT_H__ */
83