1 /*
2 * Copyright (c) 2018-2020 François Tigeot <ftigeot@wolfpond.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice unmodified, this list of conditions, and the following
10 * disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27 #ifndef _LINUX_RWSEM_H_
28 #define _LINUX_RWSEM_H_
29
30 #include <linux/types.h>
31 #include <linux/kernel.h>
32 #include <linux/list.h>
33 #include <linux/spinlock.h>
34 #include <linux/atomic.h>
35
36 #include <sys/lock.h>
37
38 #define down_read(semaphore) lockmgr((semaphore), LK_SHARED)
39 #define up_read(semaphore) lockmgr((semaphore), LK_RELEASE)
40
41 #define down_write(semaphore) lockmgr((semaphore), LK_EXCLUSIVE)
42 #define up_write(semaphore) lockmgr((semaphore), LK_RELEASE)
43
44 /*
45 * trylock for reading -- returns 1 if successful, 0 if contention
46 */
47 static inline int
down_read_trylock(struct lock * sem)48 down_read_trylock(struct lock *sem) {
49 return !lockmgr(sem, LK_EXCLUSIVE|LK_NOWAIT);
50 }
51
52 static inline int
down_write_killable(struct lock * sem)53 down_write_killable(struct lock *sem)
54 {
55 if (lockmgr(sem, LK_EXCLUSIVE|LK_SLEEPFAIL|LK_PCATCH))
56 return -EINTR;
57
58 return 0;
59 }
60
61 #endif /* _LINUX_RWSEM_H_ */
62