Add semaphore.h to kernel_lock.c
[linux-2.6.git] / include / asm-m68knommu / semaphore-helper.h
1 #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
12
13 /*
14  * These two _must_ execute atomically wrt each other.
15  */
16 static inline void wake_one_more(struct semaphore * sem)
17 {
18         atomic_inc(&sem->waking);
19 }
20
21 static 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  */
42 static 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  */
66 static 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