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Matthew Wilcox64ac24e2008-03-07 21:55:58 -05001/*
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 *
Matthew Wilcox714493c2008-04-11 15:23:52 -04007 * Please see kernel/semaphore.c for documentation of these functions
Matthew Wilcox64ac24e2008-03-07 21:55:58 -05008 */
9#ifndef __LINUX_SEMAPHORE_H
10#define __LINUX_SEMAPHORE_H
11
12#include <linux/list.h>
13#include <linux/spinlock.h>
14
Matthew Wilcox714493c2008-04-11 15:23:52 -040015/* Please don't access any members of this structure directly */
Matthew Wilcox64ac24e2008-03-07 21:55:58 -050016struct semaphore {
17 spinlock_t lock;
Matthew Wilcoxb17170b2008-03-14 14:35:22 -040018 unsigned int count;
Matthew Wilcox64ac24e2008-03-07 21:55:58 -050019 struct list_head wait_list;
20};
21
22#define __SEMAPHORE_INITIALIZER(name, n) \
23{ \
24 .lock = __SPIN_LOCK_UNLOCKED((name).lock), \
25 .count = n, \
26 .wait_list = LIST_HEAD_INIT((name).wait_list), \
27}
28
29#define __DECLARE_SEMAPHORE_GENERIC(name, count) \
30 struct semaphore name = __SEMAPHORE_INITIALIZER(name, count)
31
32#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name, 1)
33
34static inline void sema_init(struct semaphore *sem, int val)
35{
36 static struct lock_class_key __key;
37 *sem = (struct semaphore) __SEMAPHORE_INITIALIZER(*sem, val);
38 lockdep_init_map(&sem->lock.dep_map, "semaphore->lock", &__key, 0);
39}
40
41#define init_MUTEX(sem) sema_init(sem, 1)
42#define init_MUTEX_LOCKED(sem) sema_init(sem, 0)
43
Matthew Wilcox64ac24e2008-03-07 21:55:58 -050044extern void down(struct semaphore *sem);
Matthew Wilcox64ac24e2008-03-07 21:55:58 -050045extern int __must_check down_interruptible(struct semaphore *sem);
Matthew Wilcoxf06d9682008-03-14 13:19:33 -040046extern int __must_check down_killable(struct semaphore *sem);
Matthew Wilcox64ac24e2008-03-07 21:55:58 -050047extern int __must_check down_trylock(struct semaphore *sem);
Matthew Wilcoxf1241c82008-03-14 13:43:13 -040048extern int __must_check down_timeout(struct semaphore *sem, long jiffies);
Matthew Wilcox64ac24e2008-03-07 21:55:58 -050049extern void up(struct semaphore *sem);
50
51#endif /* __LINUX_SEMAPHORE_H */