projects / userspace-rcu.git / blame
| 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 */ |