1#ifndef ASMARM_SEMAPHORE_HELPER_H
2#define ASMARM_SEMAPHORE_HELPER_H
3
4/*
5 * These two _must_ execute atomically wrt each other.
6 */
7static inline void wake_one_more(struct semaphore * sem)
8{
9	unsigned long flags;
10
11	spin_lock_irqsave(&semaphore_wake_lock, flags);
12	if (atomic_read(&sem->count) <= 0)
13		sem->waking++;
14	spin_unlock_irqrestore(&semaphore_wake_lock, flags);
15}
16
17static inline int waking_non_zero(struct semaphore *sem)
18{
19	unsigned long flags;
20	int ret = 0;
21
22	spin_lock_irqsave(&semaphore_wake_lock, flags);
23	if (sem->waking > 0) {
24		sem->waking--;
25		ret = 1;
26	}
27	spin_unlock_irqrestore(&semaphore_wake_lock, flags);
28	return ret;
29}
30
31/*
32 * waking non zero interruptible
33 *	1	got the lock
34 *	0	go to sleep
35 *	-EINTR	interrupted
36 *
37 * We must undo the sem->count down_interruptible() increment while we are
38 * protected by the spinlock in order to make this atomic_inc() with the
39 * atomic_read() in wake_one_more(), otherwise we can race. -arca
40 */
41static inline int waking_non_zero_interruptible(struct semaphore *sem,
42						struct task_struct *tsk)
43{
44	unsigned long flags;
45	int ret = 0;
46
47	spin_lock_irqsave(&semaphore_wake_lock, flags);
48	if (sem->waking > 0) {
49		sem->waking--;
50		ret = 1;
51	} else if (signal_pending(tsk)) {
52		atomic_inc(&sem->count);
53		ret = -EINTR;
54	}
55	spin_unlock_irqrestore(&semaphore_wake_lock, flags);
56	return ret;
57}
58
59/*
60 * waking_non_zero_try_lock:
61 *	1	failed to lock
62 *	0	got the lock
63 *
64 * We must undo the sem->count down_interruptible() increment while we are
65 * protected by the spinlock in order to make this atomic_inc() with the
66 * atomic_read() in wake_one_more(), otherwise we can race. -arca
67 */
68static inline int waking_non_zero_trylock(struct semaphore *sem)
69{
70	unsigned long flags;
71	int ret = 1;
72
73	spin_lock_irqsave(&semaphore_wake_lock, flags);
74	if (sem->waking <= 0)
75		atomic_inc(&sem->count);
76	else {
77		sem->waking--;
78		ret = 0;
79	}
80	spin_unlock_irqrestore(&semaphore_wake_lock, flags);
81	return ret;
82}
83
84#endif
85