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/locking/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