2 * Copyright (c) 2008 Intel Corporation
3 * Author: Matthew Wilcox <willy@linux.intel.com>
5 * Distributed under the terms of the GNU GPL, version 2
7 * Please see kernel/locking/semaphore.c for documentation of these functions
9 #ifndef __LINUX_SEMAPHORE_H
10 #define __LINUX_SEMAPHORE_H
12 #include <linux/list.h>
13 #include <linux/spinlock.h>
15 /* Please don't access any members of this structure directly */
19 struct list_head wait_list
;
22 #define __SEMAPHORE_INITIALIZER(name, n) \
24 .lock = __RAW_SPIN_LOCK_UNLOCKED((name).lock), \
26 .wait_list = LIST_HEAD_INIT((name).wait_list), \
29 #define DEFINE_SEMAPHORE(name) \
30 struct semaphore name = __SEMAPHORE_INITIALIZER(name, 1)
32 static inline void sema_init(struct semaphore
*sem
, int val
)
34 static struct lock_class_key __key
;
35 *sem
= (struct semaphore
) __SEMAPHORE_INITIALIZER(*sem
, val
);
36 lockdep_init_map(&sem
->lock
.dep_map
, "semaphore->lock", &__key
, 0);
39 extern void down(struct semaphore
*sem
);
40 extern int __must_check
down_interruptible(struct semaphore
*sem
);
41 extern int __must_check
down_killable(struct semaphore
*sem
);
42 extern int __must_check
down_trylock(struct semaphore
*sem
);
43 extern int __must_check
down_timeout(struct semaphore
*sem
, long jiffies
);
44 extern void up(struct semaphore
*sem
);
46 #endif /* __LINUX_SEMAPHORE_H */