diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
---|---|---|
committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /lib/kref.c |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'lib/kref.c')
-rw-r--r-- | lib/kref.c | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/lib/kref.c b/lib/kref.c new file mode 100644 index 000000000000..0d07cc31c818 --- /dev/null +++ b/lib/kref.c | |||
@@ -0,0 +1,64 @@ | |||
1 | /* | ||
2 | * kref.c - library routines for handling generic reference counted objects | ||
3 | * | ||
4 | * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com> | ||
5 | * Copyright (C) 2004 IBM Corp. | ||
6 | * | ||
7 | * based on lib/kobject.c which was: | ||
8 | * Copyright (C) 2002-2003 Patrick Mochel <mochel@osdl.org> | ||
9 | * | ||
10 | * This file is released under the GPLv2. | ||
11 | * | ||
12 | */ | ||
13 | |||
14 | #include <linux/kref.h> | ||
15 | #include <linux/module.h> | ||
16 | |||
17 | /** | ||
18 | * kref_init - initialize object. | ||
19 | * @kref: object in question. | ||
20 | */ | ||
21 | void kref_init(struct kref *kref) | ||
22 | { | ||
23 | atomic_set(&kref->refcount,1); | ||
24 | } | ||
25 | |||
26 | /** | ||
27 | * kref_get - increment refcount for object. | ||
28 | * @kref: object. | ||
29 | */ | ||
30 | void kref_get(struct kref *kref) | ||
31 | { | ||
32 | WARN_ON(!atomic_read(&kref->refcount)); | ||
33 | atomic_inc(&kref->refcount); | ||
34 | } | ||
35 | |||
36 | /** | ||
37 | * kref_put - decrement refcount for object. | ||
38 | * @kref: object. | ||
39 | * @release: pointer to the function that will clean up the object when the | ||
40 | * last reference to the object is released. | ||
41 | * This pointer is required, and it is not acceptable to pass kfree | ||
42 | * in as this function. | ||
43 | * | ||
44 | * Decrement the refcount, and if 0, call release(). | ||
45 | * Return 1 if the object was removed, otherwise return 0. Beware, if this | ||
46 | * function returns 0, you still can not count on the kref from remaining in | ||
47 | * memory. Only use the return value if you want to see if the kref is now | ||
48 | * gone, not present. | ||
49 | */ | ||
50 | int kref_put(struct kref *kref, void (*release)(struct kref *kref)) | ||
51 | { | ||
52 | WARN_ON(release == NULL); | ||
53 | WARN_ON(release == (void (*)(struct kref *))kfree); | ||
54 | |||
55 | if (atomic_dec_and_test(&kref->refcount)) { | ||
56 | release(kref); | ||
57 | return 1; | ||
58 | } | ||
59 | return 0; | ||
60 | } | ||
61 | |||
62 | EXPORT_SYMBOL(kref_init); | ||
63 | EXPORT_SYMBOL(kref_get); | ||
64 | EXPORT_SYMBOL(kref_put); | ||