Add semaphore.h to kernel_lock.c
[linux-2.6.git] / include / asm-h8300 / semaphore-helper.h
1 #ifndef _H8300_SEMAPHORE_HELPER_H
2 #define _H8300_SEMAPHORE_HELPER_H
3
4 /*
5  * SMP- and interrupt-safe semaphores helper functions.
6  *
7  * (C) Copyright 1996 Linus Torvalds
8  *
9  * based on
10  * m68k version by Andreas Schwab
11  */
12
13 #include <linux/errno.h>
14
15 /*
16  * These two _must_ execute atomically wrt each other.
17  */
18 static inline void wake_one_more(struct semaphore * sem)
19 {
20         atomic_inc((atomic_t *)&sem->sleepers);
21 }
22
23 static inline int waking_non_zero(struct semaphore *sem)
24 {
25         int ret;
26         unsigned long flags;
27
28         spin_lock_irqsave(&semaphore_wake_lock, flags);
29         ret = 0;
30         if (sem->sleepers > 0) {
31                 sem->sleepers--;
32                 ret = 1;
33         }
34         spin_unlock_irqrestore(&semaphore_wake_lock, flags);
35         return ret;
36 }
37
38 /*
39  * waking_non_zero_interruptible:
40  *      1       got the lock
41  *      0       go to sleep
42  *      -EINTR  interrupted
43  */
44 static inline int waking_non_zero_interruptible(struct semaphore *sem,
45                                                 struct task_struct *tsk)
46 {
47         int ret;
48         unsigned long flags;
49
50         spin_lock_irqsave(&semaphore_wake_lock, flags);
51         ret = 0;
52         if (sem->sleepers > 0) {
53                 sem->sleepers--;
54                 ret = 1;
55         } else if (signal_pending(tsk)) {
56                 atomic_inc(&sem->count);
57                 ret = -EINTR;
58         }
59         spin_unlock_irqrestore(&semaphore_wake_lock, flags);
60         return ret;
61 }
62
63 /*
64  * waking_non_zero_trylock:
65  *      1       failed to lock
66  *      0       got the lock
67  */
68 static inline int waking_non_zero_trylock(struct semaphore *sem)
69 {
70         int ret;
71         unsigned long flags;
72
73         spin_lock_irqsave(&semaphore_wake_lock, flags);
74         ret = 1;
75         if (sem->sleepers <= 0)
76                 atomic_inc(&sem->count);
77         else {
78                 sem->sleepers--;
79                 ret = 0;
80         }
81         spin_unlock_irqrestore(&semaphore_wake_lock, flags);
82         return ret;
83 }
84
85 #endif