Commit | Line | Data |
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2f4f12e5 LT |
1 | #include <linux/export.h> |
2 | #include <linux/lockref.h> | |
3 | ||
4 | /** | |
5 | * lockref_get - Increments reference count unconditionally | |
6 | * @lockcnt: pointer to lockref structure | |
7 | * | |
8 | * This operation is only valid if you already hold a reference | |
9 | * to the object, so you know the count cannot be zero. | |
10 | */ | |
11 | void lockref_get(struct lockref *lockref) | |
12 | { | |
13 | spin_lock(&lockref->lock); | |
14 | lockref->count++; | |
15 | spin_unlock(&lockref->lock); | |
16 | } | |
17 | EXPORT_SYMBOL(lockref_get); | |
18 | ||
19 | /** | |
20 | * lockref_get_not_zero - Increments count unless the count is 0 | |
21 | * @lockcnt: pointer to lockref structure | |
22 | * Return: 1 if count updated successfully or 0 if count was zero | |
23 | */ | |
24 | int lockref_get_not_zero(struct lockref *lockref) | |
25 | { | |
26 | int retval = 0; | |
27 | ||
28 | spin_lock(&lockref->lock); | |
29 | if (lockref->count) { | |
30 | lockref->count++; | |
31 | retval = 1; | |
32 | } | |
33 | spin_unlock(&lockref->lock); | |
34 | return retval; | |
35 | } | |
36 | EXPORT_SYMBOL(lockref_get_not_zero); | |
37 | ||
38 | /** | |
39 | * lockref_get_or_lock - Increments count unless the count is 0 | |
40 | * @lockcnt: pointer to lockref structure | |
41 | * Return: 1 if count updated successfully or 0 if count was zero | |
42 | * and we got the lock instead. | |
43 | */ | |
44 | int lockref_get_or_lock(struct lockref *lockref) | |
45 | { | |
46 | spin_lock(&lockref->lock); | |
47 | if (!lockref->count) | |
48 | return 0; | |
49 | lockref->count++; | |
50 | spin_unlock(&lockref->lock); | |
51 | return 1; | |
52 | } | |
53 | EXPORT_SYMBOL(lockref_get_or_lock); | |
54 | ||
55 | /** | |
56 | * lockref_put_or_lock - decrements count unless count <= 1 before decrement | |
57 | * @lockcnt: pointer to lockref structure | |
58 | * Return: 1 if count updated successfully or 0 if count <= 1 and lock taken | |
59 | */ | |
60 | int lockref_put_or_lock(struct lockref *lockref) | |
61 | { | |
62 | spin_lock(&lockref->lock); | |
63 | if (lockref->count <= 1) | |
64 | return 0; | |
65 | lockref->count--; | |
66 | spin_unlock(&lockref->lock); | |
67 | return 1; | |
68 | } | |
69 | EXPORT_SYMBOL(lockref_put_or_lock); |