diff options
| -rw-r--r-- | include/linux/kref.h | 80 | ||||
| -rw-r--r-- | lib/Makefile | 2 | ||||
| -rw-r--r-- | lib/kref.c | 97 |
3 files changed, 76 insertions, 103 deletions
diff --git a/include/linux/kref.h b/include/linux/kref.h index d4a62ab..1cbae9f 100644 --- a/include/linux/kref.h +++ b/include/linux/kref.h @@ -16,15 +16,85 @@ #define _KREF_H_ #include <linux/types.h> +#include <linux/slab.h> struct kref { atomic_t refcount; }; -void kref_init(struct kref *kref); -void kref_get(struct kref *kref); -int kref_put(struct kref *kref, void (*release) (struct kref *kref)); -int kref_sub(struct kref *kref, unsigned int count, - void (*release) (struct kref *kref)); +/** + * kref_init - initialize object. + * @kref: object in question. + */ +static inline void kref_init(struct kref *kref) +{ + atomic_set(&kref->refcount, 1); + smp_mb(); +} + +/** + * kref_get - increment refcount for object. + * @kref: object. + */ +static inline void kref_get(struct kref *kref) +{ + WARN_ON(!atomic_read(&kref->refcount)); + atomic_inc(&kref->refcount); + smp_mb__after_atomic_inc(); +} + +/** + * kref_put - decrement refcount for object. + * @kref: object. + * @release: pointer to the function that will clean up the object when the + * last reference to the object is released. + * This pointer is required, and it is not acceptable to pass kfree + * in as this function. + * + * Decrement the refcount, and if 0, call release(). + * Return 1 if the object was removed, otherwise return 0. Beware, if this + * function returns 0, you still can not count on the kref from remaining in + * memory. Only use the return value if you want to see if the kref is now + * gone, not present. + */ +static inline int kref_put(struct kref *kref, void (*release)(struct kref *kref)) +{ + WARN_ON(release == NULL); + WARN_ON(release == (void (*)(struct kref *))kfree); + + if (atomic_dec_and_test(&kref->refcount)) { + release(kref); + return 1; + } + return 0; +} + + +/** + * kref_sub - subtract a number of refcounts for object. + * @kref: object. + * @count: Number of recounts to subtract. + * @release: pointer to the function that will clean up the object when the + * last reference to the object is released. + * This pointer is required, and it is not acceptable to pass kfree + * in as this function. + * + * Subtract @count from the refcount, and if 0, call release(). + * Return 1 if the object was removed, otherwise return 0. Beware, if this + * function returns 0, you still can not count on the kref from remaining in + * memory. Only use the return value if you want to see if the kref is now + * gone, not present. + */ +static inline int kref_sub(struct kref *kref, unsigned int count, + void (*release)(struct kref *kref)) +{ + WARN_ON(release == NULL); + WARN_ON(release == (void (*)(struct kref *))kfree); + if (atomic_sub_and_test((int) count, &kref->refcount)) { + release(kref); + return 1; + } + return 0; +} #endif /* _KREF_H_ */ diff --git a/lib/Makefile b/lib/Makefile index a4da283..6f195ff 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -17,7 +17,7 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \ lib-$(CONFIG_MMU) += ioremap.o lib-$(CONFIG_SMP) += cpumask.o -lib-y += kobject.o kref.o klist.o +lib-y += kobject.o klist.o obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \ bust_spinlocks.o hexdump.o kasprintf.o bitmap.o scatterlist.o \ diff --git a/lib/kref.c b/lib/kref.c deleted file mode 100644 index 3efb882..0000000 --- a/lib/kref.c +++ /dev/null @@ -1,97 +0,0 @@ -/* - * 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. - * - */ - -#include <linux/kref.h> -#include <linux/module.h> -#include <linux/slab.h> - -/** - * kref_init - initialize object. - * @kref: object in question. - */ -void kref_init(struct kref *kref) -{ - atomic_set(&kref->refcount, 1); - smp_mb(); -} - -/** - * kref_get - increment refcount for object. - * @kref: object. - */ -void kref_get(struct kref *kref) -{ - WARN_ON(!atomic_read(&kref->refcount)); - atomic_inc(&kref->refcount); - smp_mb__after_atomic_inc(); -} - -/** - * kref_put - decrement refcount for object. - * @kref: object. - * @release: pointer to the function that will clean up the object when the - * last reference to the object is released. - * This pointer is required, and it is not acceptable to pass kfree - * in as this function. - * - * Decrement the refcount, and if 0, call release(). - * Return 1 if the object was removed, otherwise return 0. Beware, if this - * function returns 0, you still can not count on the kref from remaining in - * memory. Only use the return value if you want to see if the kref is now - * gone, not present. - */ -int kref_put(struct kref *kref, void (*release)(struct kref *kref)) -{ - WARN_ON(release == NULL); - WARN_ON(release == (void (*)(struct kref *))kfree); - - if (atomic_dec_and_test(&kref->refcount)) { - release(kref); - return 1; - } - return 0; -} - - -/** - * kref_sub - subtract a number of refcounts for object. - * @kref: object. - * @count: Number of recounts to subtract. - * @release: pointer to the function that will clean up the object when the - * last reference to the object is released. - * This pointer is required, and it is not acceptable to pass kfree - * in as this function. - * - * Subtract @count from the refcount, and if 0, call release(). - * Return 1 if the object was removed, otherwise return 0. Beware, if this - * function returns 0, you still can not count on the kref from remaining in - * memory. Only use the return value if you want to see if the kref is now - * gone, not present. - */ -int kref_sub(struct kref *kref, unsigned int count, - void (*release)(struct kref *kref)) -{ - WARN_ON(release == NULL); - WARN_ON(release == (void (*)(struct kref *))kfree); - - if (atomic_sub_and_test((int) count, &kref->refcount)) { - release(kref); - return 1; - } - return 0; -} - -EXPORT_SYMBOL(kref_init); -EXPORT_SYMBOL(kref_get); -EXPORT_SYMBOL(kref_put); -EXPORT_SYMBOL(kref_sub); |
