1 /* SPDX-License-Identifier: GPL-2.0-only */ 1
2 /*
3 * Copyright (c) 2008 Intel Corporation
4 * Author: Matthew Wilcox <willy@linux.intel.c
5 *
6 * Please see kernel/locking/semaphore.c for d
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 str
15 struct 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_UNLO
24 .count = n,
25 .wait_list = LIST_HEAD_INIT((name
26 }
27
28 /*
29 * Unlike mutexes, binary semaphores do not ha
30 * be called in a different thread from the on
31 * It is also safe to call down_trylock() and
32 * context.
33 */
34 #define DEFINE_SEMAPHORE(_name, _n) \
35 struct semaphore _name = __SEMAPHORE_I
36
37 static inline void sema_init(struct semaphore
38 {
39 static struct lock_class_key __key;
40 *sem = (struct semaphore) __SEMAPHORE_
41 lockdep_init_map(&sem->lock.dep_map, "
42 }
43
44 extern void down(struct semaphore *sem);
45 extern int __must_check down_interruptible(str
46 extern int __must_check down_killable(struct s
47 extern int __must_check down_trylock(struct se
48 extern int __must_check down_timeout(struct se
49 extern void up(struct semaphore *sem);
50
51 #endif /* __LINUX_SEMAPHORE_H */
52
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