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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef _M68K_SEMAPHORE_HELPER_H
2#define _M68K_SEMAPHORE_HELPER_H
3
4/*
5 * SMP- and interrupt-safe semaphores helper functions.
6 *
7 * (C) Copyright 1996 Linus Torvalds
8 *
9 * m68k version by Andreas Schwab
10 */
11
Linus Torvalds1da177e2005-04-16 15:20:36 -070012
13/*
14 * These two _must_ execute atomically wrt each other.
15 */
16static inline void wake_one_more(struct semaphore * sem)
17{
18 atomic_inc(&sem->waking);
19}
20
21static inline int waking_non_zero(struct semaphore *sem)
22{
23 int ret;
24 unsigned long flags;
25
26 spin_lock_irqsave(&semaphore_wake_lock, flags);
27 ret = 0;
28 if (atomic_read(&sem->waking) > 0) {
29 atomic_dec(&sem->waking);
30 ret = 1;
31 }
32 spin_unlock_irqrestore(&semaphore_wake_lock, flags);
33 return ret;
34}
35
36/*
37 * waking_non_zero_interruptible:
38 * 1 got the lock
39 * 0 go to sleep
40 * -EINTR interrupted
41 */
42static inline int waking_non_zero_interruptible(struct semaphore *sem,
43 struct task_struct *tsk)
44{
45 int ret;
46 unsigned long flags;
47
48 spin_lock_irqsave(&semaphore_wake_lock, flags);
49 ret = 0;
50 if (atomic_read(&sem->waking) > 0) {
51 atomic_dec(&sem->waking);
52 ret = 1;
53 } else if (signal_pending(tsk)) {
54 atomic_inc(&sem->count);
55 ret = -EINTR;
56 }
57 spin_unlock_irqrestore(&semaphore_wake_lock, flags);
58 return ret;
59}
60
61/*
62 * waking_non_zero_trylock:
63 * 1 failed to lock
64 * 0 got the lock
65 */
66static inline int waking_non_zero_trylock(struct semaphore *sem)
67{
68 int ret;
69 unsigned long flags;
70
71 spin_lock_irqsave(&semaphore_wake_lock, flags);
72 ret = 1;
73 if (atomic_read(&sem->waking) > 0) {
74 atomic_dec(&sem->waking);
75 ret = 0;
76 } else
77 atomic_inc(&sem->count);
78 spin_unlock_irqrestore(&semaphore_wake_lock, flags);
79 return ret;
80}
81
82#endif