6b13f685e
 김민수
BSP 최초 추가
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
|
/* rwsem-spinlock.h: fallback C implementation
*
* Copyright (c) 2001 David Howells (dhowells@redhat.com).
* - Derived partially from ideas by Andrea Arcangeli <andrea@suse.de>
* - Derived also from comments by Linus
*/
#ifndef _LINUX_RWSEM_SPINLOCK_H
#define _LINUX_RWSEM_SPINLOCK_H
#ifndef _LINUX_RWSEM_H
#error "please don't include linux/rwsem-spinlock.h directly, use linux/rwsem.h instead"
#endif
#ifdef __KERNEL__
/*
* the rw-semaphore definition
* - if activity is 0 then there are no active readers or writers
* - if activity is +ve then that is the number of active readers
* - if activity is -1 then there is one active writer
* - if wait_list is not empty, then there are processes waiting for the semaphore
*/
struct rw_semaphore {
__s32 activity;
raw_spinlock_t wait_lock;
struct list_head wait_list;
#ifdef CONFIG_DEBUG_LOCK_ALLOC
struct lockdep_map dep_map;
#endif
};
#define RWSEM_UNLOCKED_VALUE 0x00000000
extern void __down_read(struct rw_semaphore *sem);
extern int __down_read_trylock(struct rw_semaphore *sem);
extern void __down_write(struct rw_semaphore *sem);
extern void __down_write_nested(struct rw_semaphore *sem, int subclass);
extern int __down_write_trylock(struct rw_semaphore *sem);
extern void __up_read(struct rw_semaphore *sem);
extern void __up_write(struct rw_semaphore *sem);
extern void __downgrade_write(struct rw_semaphore *sem);
extern int rwsem_is_locked(struct rw_semaphore *sem);
#endif /* __KERNEL__ */
#endif /* _LINUX_RWSEM_SPINLOCK_H */
|