[linux-block.git] / include / linux / semaphore.h

/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright (c) 2008 Intel Corporation
 * Author: Matthew Wilcox <willy@linux.intel.com>
 *
 * Please see kernel/locking/semaphore.c for documentation of these functions
 */
#ifndef __LINUX_SEMAPHORE_H
#define __LINUX_SEMAPHORE_H

#include <linux/list.h>
#include <linux/spinlock.h>

/* Please don't access any members of this structure directly */
struct semaphore {
	raw_spinlock_t		lock;
	unsigned int		count;
	struct list_head	wait_list;
};

#define __SEMAPHORE_INITIALIZER(name, n)				\
{									\
	.lock		= __RAW_SPIN_LOCK_UNLOCKED((name).lock),	\
	.count		= n,						\
	.wait_list	= LIST_HEAD_INIT((name).wait_list),		\
}

/*
 * Unlike mutexes, binary semaphores do not have an owner, so up() can
 * be called in a different thread from the one which called down().
 * It is also safe to call down_trylock() and up() from interrupt
 * context.
 */
#define DEFINE_SEMAPHORE(_name, _n)	\
	struct semaphore _name = __SEMAPHORE_INITIALIZER(_name, _n)

static inline void sema_init(struct semaphore *sem, int val)
{
	static struct lock_class_key __key;
	*sem = (struct semaphore) __SEMAPHORE_INITIALIZER(*sem, val);
	lockdep_init_map(&sem->lock.dep_map, "semaphore->lock", &__key, 0);
}

extern void down(struct semaphore *sem);
extern int __must_check down_interruptible(struct semaphore *sem);
extern int __must_check down_killable(struct semaphore *sem);
extern int __must_check down_trylock(struct semaphore *sem);
extern int __must_check down_timeout(struct semaphore *sem, long jiffies);
extern void up(struct semaphore *sem);

#endif /* __LINUX_SEMAPHORE_H */
Commit	Line	Data
3e456101	1	/* SPDX-License-Identifier: GPL-2.0-only */
64ac24e7 MW	2	/*
	3	* Copyright (c) 2008 Intel Corporation
	4	* Author: Matthew Wilcox <willy@linux.intel.com>
	5	*
2dd6fd2e	6	* Please see kernel/locking/semaphore.c for documentation of these functions
64ac24e7 MW	7	*/
	8	#ifndef __LINUX_SEMAPHORE_H
	9	#define __LINUX_SEMAPHORE_H
	10
	11	#include <linux/list.h>
	12	#include <linux/spinlock.h>
	13
714493cd	14	/* Please don't access any members of this structure directly */
64ac24e7	15	struct semaphore {
8292c9e1	16	raw_spinlock_t lock;
b17170b2	17	unsigned int count;
64ac24e7 MW	18	struct list_head wait_list;
	19	};
	20
	21	#define __SEMAPHORE_INITIALIZER(name, n) \
	22	{ \
8292c9e1	23	.lock = __RAW_SPIN_LOCK_UNLOCKED((name).lock), \
64ac24e7 MW	24	.count = n, \
	25	.wait_list = LIST_HEAD_INIT((name).wait_list), \
	26	}
	27
48380368 PZ	28	/*
	29	* Unlike mutexes, binary semaphores do not have an owner, so up() can
	30	* be called in a different thread from the one which called down().
	31	* It is also safe to call down_trylock() and up() from interrupt
	32	* context.
	33	*/
	34	#define DEFINE_SEMAPHORE(_name, _n) \
	35	struct semaphore _name = __SEMAPHORE_INITIALIZER(_name, _n)
febc88c5	36
64ac24e7 MW	37	static inline void sema_init(struct semaphore *sem, int val)
	38	{
	39	static struct lock_class_key __key;
	40	sem = (struct semaphore) __SEMAPHORE_INITIALIZER(sem, val);
	41	lockdep_init_map(&sem->lock.dep_map, "semaphore->lock", &__key, 0);
	42	}
	43
64ac24e7	44	extern void down(struct semaphore *sem);
64ac24e7	45	extern int __must_check down_interruptible(struct semaphore *sem);
f06d9686	46	extern int __must_check down_killable(struct semaphore *sem);
64ac24e7	47	extern int __must_check down_trylock(struct semaphore *sem);
f1241c87	48	extern int __must_check down_timeout(struct semaphore *sem, long jiffies);
64ac24e7 MW	49	extern void up(struct semaphore *sem);
	50
	51	#endif /* __LINUX_SEMAPHORE_H */