diff options
author | Paul Mundt <lethal@linux-sh.org> | 2012-01-09 11:12:55 +0900 |
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committer | Paul Mundt <lethal@linux-sh.org> | 2012-01-09 11:12:55 +0900 |
commit | ca371d2854d48c0c22e7aa031df182f96dc85820 (patch) | |
tree | 1c62be8b4da0bfc82fa7ffa1ad5b0e958266cbd1 /include/linux/kref.h | |
parent | 0d376945d0bc0a8f8e00861d506b10e42e8af372 (diff) | |
parent | a0e86bd4252519321b0d102dc4ed90557aa7bee9 (diff) |
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into sh-latest
Conflicts:
arch/arm/mach-shmobile/clock-sh73a0.c
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'include/linux/kref.h')
-rw-r--r-- | include/linux/kref.h | 77 |
1 files changed, 71 insertions, 6 deletions
diff --git a/include/linux/kref.h b/include/linux/kref.h index d4a62ab2ee5e..abc0120b09b7 100644 --- a/include/linux/kref.h +++ b/include/linux/kref.h @@ -15,16 +15,81 @@ #ifndef _KREF_H_ #define _KREF_H_ -#include <linux/types.h> +#include <linux/bug.h> +#include <linux/atomic.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); +} + +/** + * 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); +} +/** + * 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. If the caller does pass kfree to this + * function, you will be publicly mocked mercilessly by the kref + * maintainer, and anyone else who happens to notice it. You have + * been warned. + * + * 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); + + if (atomic_sub_and_test((int) count, &kref->refcount)) { + release(kref); + return 1; + } + return 0; +} + +/** + * 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. If the caller does pass kfree to this + * function, you will be publicly mocked mercilessly by the kref + * maintainer, and anyone else who happens to notice it. You have + * been warned. + * + * 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)) +{ + return kref_sub(kref, 1, release); +} #endif /* _KREF_H_ */ |