semaphore.h (1384B)
1/* SPDX-License-Identifier: GPL-2.0-only */ 2/* 3 * Copyright (c) 2008 Intel Corporation 4 * Author: Matthew Wilcox <willy@linux.intel.com> 5 * 6 * Please see kernel/locking/semaphore.c for documentation of these functions 7 */ 8#ifndef __LINUX_SEMAPHORE_H 9#define __LINUX_SEMAPHORE_H 10 11#include <linux/list.h> 12#include <linux/spinlock.h> 13 14/* Please don't access any members of this structure directly */ 15struct semaphore { 16 raw_spinlock_t lock; 17 unsigned int count; 18 struct list_head wait_list; 19}; 20 21#define __SEMAPHORE_INITIALIZER(name, n) \ 22{ \ 23 .lock = __RAW_SPIN_LOCK_UNLOCKED((name).lock), \ 24 .count = n, \ 25 .wait_list = LIST_HEAD_INIT((name).wait_list), \ 26} 27 28#define DEFINE_SEMAPHORE(name) \ 29 struct semaphore name = __SEMAPHORE_INITIALIZER(name, 1) 30 31static inline void sema_init(struct semaphore *sem, int val) 32{ 33 static struct lock_class_key __key; 34 *sem = (struct semaphore) __SEMAPHORE_INITIALIZER(*sem, val); 35 lockdep_init_map(&sem->lock.dep_map, "semaphore->lock", &__key, 0); 36} 37 38extern void down(struct semaphore *sem); 39extern int __must_check down_interruptible(struct semaphore *sem); 40extern int __must_check down_killable(struct semaphore *sem); 41extern int __must_check down_trylock(struct semaphore *sem); 42extern int __must_check down_timeout(struct semaphore *sem, long jiffies); 43extern void up(struct semaphore *sem); 44 45#endif /* __LINUX_SEMAPHORE_H */