blob: a9a4f4e1eff5b681b779519a490461801dd35820 (
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
|
#include <linux/export.h>
#include <linux/lockref.h>
/**
* lockref_get - Increments reference count unconditionally
* @lockcnt: pointer to lockref structure
*
* This operation is only valid if you already hold a reference
* to the object, so you know the count cannot be zero.
*/
void lockref_get(struct lockref *lockref)
{
spin_lock(&lockref->lock);
lockref->count++;
spin_unlock(&lockref->lock);
}
EXPORT_SYMBOL(lockref_get);
/**
* lockref_get_not_zero - Increments count unless the count is 0
* @lockcnt: pointer to lockref structure
* Return: 1 if count updated successfully or 0 if count was zero
*/
int lockref_get_not_zero(struct lockref *lockref)
{
int retval = 0;
spin_lock(&lockref->lock);
if (lockref->count) {
lockref->count++;
retval = 1;
}
spin_unlock(&lockref->lock);
return retval;
}
EXPORT_SYMBOL(lockref_get_not_zero);
/**
* lockref_get_or_lock - Increments count unless the count is 0
* @lockcnt: pointer to lockref structure
* Return: 1 if count updated successfully or 0 if count was zero
* and we got the lock instead.
*/
int lockref_get_or_lock(struct lockref *lockref)
{
spin_lock(&lockref->lock);
if (!lockref->count)
return 0;
lockref->count++;
spin_unlock(&lockref->lock);
return 1;
}
EXPORT_SYMBOL(lockref_get_or_lock);
/**
* lockref_put_or_lock - decrements count unless count <= 1 before decrement
* @lockcnt: pointer to lockref structure
* Return: 1 if count updated successfully or 0 if count <= 1 and lock taken
*/
int lockref_put_or_lock(struct lockref *lockref)
{
spin_lock(&lockref->lock);
if (lockref->count <= 1)
return 0;
lockref->count--;
spin_unlock(&lockref->lock);
return 1;
}
EXPORT_SYMBOL(lockref_put_or_lock);
|
