Commit | Line | Data |
---|---|---|
453629a9 MD |
1 | #ifndef _URCU_REF_H |
2 | #define _URCU_REF_H | |
3 | ||
4 | /* | |
5 | * Userspace RCU - Reference counting | |
6 | * | |
7 | * Copyright (C) 2009 Novell Inc. | |
8 | * Copyright (C) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
9 | * | |
10 | * Author: Jan Blunck <jblunck@suse.de> | |
11 | * | |
12 | * This program is free software; you can redistribute it and/or modify it | |
13 | * under the terms of the GNU Lesser General Public License version 2.1 as | |
14 | * published by the Free Software Foundation. | |
15 | */ | |
16 | ||
17 | #include <assert.h> | |
3a03e6f3 MD |
18 | #include <limits.h> |
19 | #include <stdlib.h> | |
a2e7bf9c | 20 | #include <urcu/uatomic.h> |
453629a9 MD |
21 | |
22 | struct urcu_ref { | |
23 | long refcount; /* ATOMIC */ | |
24 | }; | |
25 | ||
26 | static inline void urcu_ref_set(struct urcu_ref *ref, long val) | |
27 | { | |
28 | uatomic_set(&ref->refcount, val); | |
29 | } | |
30 | ||
31 | static inline void urcu_ref_init(struct urcu_ref *ref) | |
32 | { | |
33 | urcu_ref_set(ref, 1); | |
34 | } | |
35 | ||
36 | static inline void urcu_ref_get(struct urcu_ref *ref) | |
37 | { | |
3a03e6f3 MD |
38 | long old, _new, res; |
39 | ||
40 | old = uatomic_read(&ref->refcount); | |
41 | for (;;) { | |
42 | if (old == LONG_MAX) { | |
43 | abort(); | |
44 | } | |
45 | _new = old + 1; | |
46 | res = uatomic_cmpxchg(&ref->refcount, old, _new); | |
47 | if (res == old) { | |
48 | return; | |
49 | } | |
50 | old = res; | |
51 | } | |
453629a9 MD |
52 | } |
53 | ||
54 | static inline void urcu_ref_put(struct urcu_ref *ref, | |
55 | void (*release)(struct urcu_ref *)) | |
56 | { | |
bf27322d PB |
57 | long res = uatomic_sub_return(&ref->refcount, 1); |
58 | assert (res >= 0); | |
59 | if (res == 0) | |
453629a9 MD |
60 | release(ref); |
61 | } | |
62 | ||
63 | #endif /* _URCU_REF_H */ |