1/*
2 * Copyright (c) 2008 Intel Corporation
3 * Author: Matthew Wilcox <willy@linux.intel.com>
4 *
5 * Distributed under the terms of the GNU GPL, version 2
6 *
7 * Please see kernel/semaphore.c for documentation of these functions
8 */
9#ifndef __LINUX_SEMAPHORE_H
10#define __LINUX_SEMAPHORE_H
11
12#include <linux/list.h>
13#include <linux/spinlock.h>
14
15/* Please don't access any members of this structure directly */
16struct semaphore {
17	raw_spinlock_t		lock;
18	unsigned int		count;
19	struct list_head	wait_list;
20};
21
22#define __SEMAPHORE_INITIALIZER(name, n)				\
23{									\
24	.lock		= __RAW_SPIN_LOCK_UNLOCKED((name).lock),	\
25	.count		= n,						\
26	.wait_list	= LIST_HEAD_INIT((name).wait_list),		\
27}
28
29#define DEFINE_SEMAPHORE(name)	\
30	struct semaphore name = __SEMAPHORE_INITIALIZER(name, 1)
31
32static inline void sema_init(struct semaphore *sem, int val)
33{
34	static struct lock_class_key __key;
35	*sem = (struct semaphore) __SEMAPHORE_INITIALIZER(*sem, val);
36	lockdep_init_map(&sem->lock.dep_map, "semaphore->lock", &__key, 0);
37}
38
39extern void down(struct semaphore *sem);
40extern int __must_check down_interruptible(struct semaphore *sem);
41extern int __must_check down_killable(struct semaphore *sem);
42extern int __must_check down_trylock(struct semaphore *sem);
43extern int __must_check down_timeout(struct semaphore *sem, long jiffies);
44extern void up(struct semaphore *sem);
45
46#endif /* __LINUX_SEMAPHORE_H */
47