blob: dbd0f30b85b6aa7653da1e85edd9165d41c9d3a4 (
plain)
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
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
|
/* $Id: semaphore-helper.h,v 1.3 2001/03/26 15:00:33 orjanf Exp $
*
* SMP- and interrupt-safe semaphores helper functions. Generic versions, no
* optimizations whatsoever...
*
*/
#ifndef _ASM_SEMAPHORE_HELPER_H
#define _ASM_SEMAPHORE_HELPER_H
#include <asm/atomic.h>
#include <linux/errno.h>
#define read(a) ((a)->counter)
#define inc(a) (((a)->counter)++)
#define dec(a) (((a)->counter)--)
#define count_inc(a) ((*(a))++)
/*
* These two _must_ execute atomically wrt each other.
*/
extern inline void wake_one_more(struct semaphore * sem)
{
atomic_inc(&sem->waking);
}
extern inline int waking_non_zero(struct semaphore *sem)
{
unsigned long flags;
int ret = 0;
local_save_flags(flags);
local_irq_disable();
if (read(&sem->waking) > 0) {
dec(&sem->waking);
ret = 1;
}
local_irq_restore(flags);
return ret;
}
extern inline int waking_non_zero_interruptible(struct semaphore *sem,
struct task_struct *tsk)
{
int ret = 0;
unsigned long flags;
local_save_flags(flags);
local_irq_disable();
if (read(&sem->waking) > 0) {
dec(&sem->waking);
ret = 1;
} else if (signal_pending(tsk)) {
inc(&sem->count);
ret = -EINTR;
}
local_irq_restore(flags);
return ret;
}
extern inline int waking_non_zero_trylock(struct semaphore *sem)
{
int ret = 1;
unsigned long flags;
local_save_flags(flags);
local_irq_disable();
if (read(&sem->waking) <= 0)
inc(&sem->count);
else {
dec(&sem->waking);
ret = 0;
}
local_irq_restore(flags);
return ret;
}
#endif /* _ASM_SEMAPHORE_HELPER_H */
|
