1 | /* $NetBSD: rwsem.h,v 1.1 2014/07/16 20:59:58 riastradh Exp $ */ |
2 | |
3 | /*- |
4 | * Copyright (c) 2014 The NetBSD Foundation, Inc. |
5 | * All rights reserved. |
6 | * |
7 | * This code is derived from software contributed to The NetBSD Foundation |
8 | * by Taylor R. Campbell. |
9 | * |
10 | * Redistribution and use in source and binary forms, with or without |
11 | * modification, are permitted provided that the following conditions |
12 | * are met: |
13 | * 1. Redistributions of source code must retain the above copyright |
14 | * notice, this list of conditions and the following disclaimer. |
15 | * 2. Redistributions in binary form must reproduce the above copyright |
16 | * notice, this list of conditions and the following disclaimer in the |
17 | * documentation and/or other materials provided with the distribution. |
18 | * |
19 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
20 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
21 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
22 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
23 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
24 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
25 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
26 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
27 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
28 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
29 | * POSSIBILITY OF SUCH DAMAGE. |
30 | */ |
31 | |
32 | /* |
33 | * These are not really semaphores; they are just reader/writer sleep |
34 | * locks, whereas what Linux calls an rwlock is a reader/writer spin |
35 | * lock. |
36 | * |
37 | * Notes on porting: |
38 | * |
39 | * - Linux does not have destroy_rwsem. You must add it yourself in |
40 | * the appropriate place. |
41 | */ |
42 | |
43 | #ifndef _LINUX_RWSEM_H_ |
44 | #define _LINUX_RWSEM_H_ |
45 | |
46 | #include <sys/mutex.h> |
47 | |
48 | struct rw_semaphore { |
49 | krwlock_t rws_lock; |
50 | }; |
51 | |
52 | static inline void |
53 | init_rwsem(struct rw_semaphore *rwsem) |
54 | { |
55 | |
56 | rw_init(&rwsem->rws_lock); |
57 | } |
58 | |
59 | static inline void |
60 | destroy_rwsem(struct rw_semaphore *rwsem) |
61 | { |
62 | |
63 | rw_destroy(&rwsem->rws_lock); |
64 | } |
65 | |
66 | static inline void |
67 | down_read(struct rw_semaphore *rwsem) |
68 | { |
69 | |
70 | rw_enter(&rwsem->rws_lock, RW_READER); |
71 | } |
72 | |
73 | static inline void |
74 | down_write(struct rw_semaphore *rwsem) |
75 | { |
76 | |
77 | rw_enter(&rwsem->rws_lock, RW_WRITER); |
78 | } |
79 | |
80 | static inline void |
81 | up_read(struct rw_semaphore *rwsem) |
82 | { |
83 | |
84 | rw_exit(&rwsem->rws_lock); |
85 | } |
86 | |
87 | static inline void |
88 | up_write(struct rw_semaphore *rwsem) |
89 | { |
90 | |
91 | rw_exit(&rwsem->rws_lock); |
92 | } |
93 | |
94 | #endif /* _LINUX_RWSEM_H_ */ |
95 | |