diff options
author | Greg Kroah-Hartman <greg@kroah.com> | 2004-03-14 22:39:18 -0800 |
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committer | Greg Kroah-Hartman <greg@kroah.com> | 2004-03-14 22:39:18 -0800 |
commit | 04e52ea83772c5e47c0f36328c10f21e744d57ba (patch) | |
tree | fbdff73665d259e700925301d47a8503699b7ed2 /lib | |
parent | a538fe37e9f04a5b9eebc3f22ce190717d854296 (diff) | |
download | history-04e52ea83772c5e47c0f36328c10f21e744d57ba.tar.gz |
kref: add kref structure to kernel tree.
Based on the kobject structure, but much smaller and simpler to use.
Diffstat (limited to 'lib')
-rw-r--r-- | lib/Makefile | 3 | ||||
-rw-r--r-- | lib/kref.c | 60 |
2 files changed, 63 insertions, 0 deletions
diff --git a/lib/Makefile b/lib/Makefile index c489f79b9dfa3a..961bac2e6166f6 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -8,6 +8,9 @@ lib-y := errno.o ctype.o string.o vsprintf.o cmdline.o \ kobject.o idr.o div64.o parser.o int_sqrt.o \ bitmap.o extable.o +# hack for now till some static code uses krefs, then it can move up above... +obj-y += kref.o + lib-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o diff --git a/lib/kref.c b/lib/kref.c new file mode 100644 index 00000000000000..ee141adbf2e558 --- /dev/null +++ b/lib/kref.c @@ -0,0 +1,60 @@ +/* + * kref.c - library routines for handling generic reference counted objects + * + * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com> + * Copyright (C) 2004 IBM Corp. + * + * based on lib/kobject.c which was: + * Copyright (C) 2002-2003 Patrick Mochel <mochel@osdl.org> + * + * This file is released under the GPLv2. + * + */ + +/* #define DEBUG */ + +#include <linux/kref.h> +#include <linux/module.h> + +/** + * kref_init - initialize object. + * @kref: object in question. + * @release: pointer to a function that will clean up the object + * when the last reference to the object is released. + * This pointer is required. + */ +void kref_init(struct kref *kref, void (*release)(struct kref *kref)) +{ + WARN_ON(release == NULL); + atomic_set(&kref->refcount,1); + kref->release = release; +} + +/** + * kref_get - increment refcount for object. + * @kref: object. + */ +struct kref *kref_get(struct kref *kref) +{ + WARN_ON(!atomic_read(&kref->refcount)); + atomic_inc(&kref->refcount); + return kref; +} + +/** + * kref_put - decrement refcount for object. + * @kref: object. + * + * Decrement the refcount, and if 0, call kref->release(). + */ +void kref_put(struct kref *kref) +{ + if (atomic_dec_and_test(&kref->refcount)) { + pr_debug("kref cleaning up\n"); + kref->release(kref); + } +} + +EXPORT_SYMBOL(kref_init); +EXPORT_SYMBOL(kref_get); +EXPORT_SYMBOL(kref_put); |