1 /* SPDX-License-Identifier: GPL-2.0-only */ <<
2 /* 1 /*
3 * Copyright (c) 2008 Intel Corporation 2 * Copyright (c) 2008 Intel Corporation
4 * Author: Matthew Wilcox <willy@linux.intel.c 3 * Author: Matthew Wilcox <willy@linux.intel.com>
5 * 4 *
>> 5 * Distributed under the terms of the GNU GPL, version 2
>> 6 *
6 * Please see kernel/locking/semaphore.c for d 7 * Please see kernel/locking/semaphore.c for documentation of these functions
7 */ 8 */
8 #ifndef __LINUX_SEMAPHORE_H 9 #ifndef __LINUX_SEMAPHORE_H
9 #define __LINUX_SEMAPHORE_H 10 #define __LINUX_SEMAPHORE_H
10 11
11 #include <linux/list.h> 12 #include <linux/list.h>
12 #include <linux/spinlock.h> 13 #include <linux/spinlock.h>
13 14
14 /* Please don't access any members of this str 15 /* Please don't access any members of this structure directly */
15 struct semaphore { 16 struct semaphore {
16 raw_spinlock_t lock; 17 raw_spinlock_t lock;
17 unsigned int count; 18 unsigned int count;
18 struct list_head wait_list; 19 struct list_head wait_list;
19 }; 20 };
20 21
21 #define __SEMAPHORE_INITIALIZER(name, n) 22 #define __SEMAPHORE_INITIALIZER(name, n) \
22 { 23 { \
23 .lock = __RAW_SPIN_LOCK_UNLO 24 .lock = __RAW_SPIN_LOCK_UNLOCKED((name).lock), \
24 .count = n, 25 .count = n, \
25 .wait_list = LIST_HEAD_INIT((name 26 .wait_list = LIST_HEAD_INIT((name).wait_list), \
26 } 27 }
27 28
28 /* !! 29 #define DEFINE_SEMAPHORE(name) \
29 * Unlike mutexes, binary semaphores do not ha !! 30 struct semaphore name = __SEMAPHORE_INITIALIZER(name, 1)
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 31
37 static inline void sema_init(struct semaphore 32 static inline void sema_init(struct semaphore *sem, int val)
38 { 33 {
39 static struct lock_class_key __key; 34 static struct lock_class_key __key;
40 *sem = (struct semaphore) __SEMAPHORE_ 35 *sem = (struct semaphore) __SEMAPHORE_INITIALIZER(*sem, val);
41 lockdep_init_map(&sem->lock.dep_map, " 36 lockdep_init_map(&sem->lock.dep_map, "semaphore->lock", &__key, 0);
42 } 37 }
43 38
44 extern void down(struct semaphore *sem); 39 extern void down(struct semaphore *sem);
45 extern int __must_check down_interruptible(str 40 extern int __must_check down_interruptible(struct semaphore *sem);
46 extern int __must_check down_killable(struct s 41 extern int __must_check down_killable(struct semaphore *sem);
47 extern int __must_check down_trylock(struct se 42 extern int __must_check down_trylock(struct semaphore *sem);
48 extern int __must_check down_timeout(struct se 43 extern int __must_check down_timeout(struct semaphore *sem, long jiffies);
49 extern void up(struct semaphore *sem); 44 extern void up(struct semaphore *sem);
50 45
51 #endif /* __LINUX_SEMAPHORE_H */ 46 #endif /* __LINUX_SEMAPHORE_H */
52 47
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