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 spinlock_t lock; 18 unsigned int count; 19 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 DEFINE_SEMAPHORE(name) \ 30 struct semaphore name = __SEMAPHORE_INITIALIZER(name, 1) 31 32#define DECLARE_MUTEX(name) \ 33 struct semaphore name = __SEMAPHORE_INITIALIZER(name, 1) 34 35static inline void sema_init(struct semaphore *sem, int val) 36{ 37 static struct lock_class_key __key; 38 *sem = (struct semaphore) __SEMAPHORE_INITIALIZER(*sem, val); 39 lockdep_init_map(&sem->lock.dep_map, "semaphore->lock", &__key, 0); 40} 41 42#define init_MUTEX(sem) sema_init(sem, 1) 43#define init_MUTEX_LOCKED(sem) sema_init(sem, 0) 44 45extern void down(struct semaphore *sem); 46extern int __must_check down_interruptible(struct semaphore *sem); 47extern int __must_check down_killable(struct semaphore *sem); 48extern int __must_check down_trylock(struct semaphore *sem); 49extern int __must_check down_timeout(struct semaphore *sem, long jiffies); 50extern void up(struct semaphore *sem); 51 52#endif /* __LINUX_SEMAPHORE_H */ 53