[TCP]: NAGLE_PUSH seems to be a wrong way around
[linux-2.6/sactl.git] / lib / kref.c
bloba6dc3ec328e05fc8da4d69d185d13a5758ac0464
1 /*
2 * kref.c - library routines for handling generic reference counted objects
4 * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
5 * Copyright (C) 2004 IBM Corp.
7 * based on lib/kobject.c which was:
8 * Copyright (C) 2002-2003 Patrick Mochel <mochel@osdl.org>
10 * This file is released under the GPLv2.
14 #include <linux/kref.h>
15 #include <linux/module.h>
17 /**
18 * kref_init - initialize object.
19 * @kref: object in question.
21 void kref_init(struct kref *kref)
23 atomic_set(&kref->refcount,1);
24 smp_mb();
27 /**
28 * kref_get - increment refcount for object.
29 * @kref: object.
31 void kref_get(struct kref *kref)
33 WARN_ON(!atomic_read(&kref->refcount));
34 atomic_inc(&kref->refcount);
35 smp_mb__after_atomic_inc();
38 /**
39 * kref_put - decrement refcount for object.
40 * @kref: object.
41 * @release: pointer to the function that will clean up the object when the
42 * last reference to the object is released.
43 * This pointer is required, and it is not acceptable to pass kfree
44 * in as this function.
46 * Decrement the refcount, and if 0, call release().
47 * Return 1 if the object was removed, otherwise return 0. Beware, if this
48 * function returns 0, you still can not count on the kref from remaining in
49 * memory. Only use the return value if you want to see if the kref is now
50 * gone, not present.
52 int kref_put(struct kref *kref, void (*release)(struct kref *kref))
54 WARN_ON(release == NULL);
55 WARN_ON(release == (void (*)(struct kref *))kfree);
57 if (atomic_dec_and_test(&kref->refcount)) {
58 release(kref);
59 return 1;
61 return 0;
64 EXPORT_SYMBOL(kref_init);
65 EXPORT_SYMBOL(kref_get);
66 EXPORT_SYMBOL(kref_put);