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 
29 #ifndef _LINUXKPI_LINUX_REFCOUNT_H
30 #define _LINUXKPI_LINUX_REFCOUNT_H
31 
32 #include <linux/atomic.h>
33 
34 struct refcount_linux {
35 	atomic_t value;
36 };
37 typedef struct refcount_linux refcount_t;
38 
39 static inline void
40 refcount_set(refcount_t *ref, unsigned int i)
41 {
42 	atomic_set(&ref->value, i);
43 }
44 
45 static inline void
46 refcount_inc(refcount_t *ref)
47 {
48 	atomic_inc(&ref->value);
49 }
50 
51 static inline bool
52 refcount_inc_not_zero(refcount_t *ref)
53 {
54 	return (atomic_inc_not_zero(&ref->value));
55 }
56 
57 static inline void
58 refcount_dec(refcount_t *ref)
59 {
60 	atomic_dec(&ref->value);
61 }
62 
63 static inline unsigned int
64 refcount_read(refcount_t *ref)
65 {
66 	return atomic_read(&ref->value);
67 }
68 
69 static inline bool
70 refcount_dec_and_lock_irqsave(refcount_t *ref, spinlock_t *lock,
71     unsigned long *flags)
72 {
73 	if (atomic_dec_and_test(&ref->value) == true) {
74 		spin_lock_irqsave(lock, flags);
75 		return (true);
76 	}
77 	return (false);
78 }
79 
80 /*
81  * struct kref uses atomic_t and not refcount_t so
82  * we differ from Linux here.
83  */
84 static inline bool
85 refcount_dec_and_test(atomic_t *r)
86 {
87 
88 	return (atomic_dec_and_test(r));
89 }
90 
91 #endif /* __LINUXKPI_LINUX_REFCOUNT_H__ */
92