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Commit 47dbd7d9 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Greg Kroah-Hartman
Browse files

kref: Implement kref_put in terms of kref_sub 



Less lines of code is better.

Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 4af679cd

include/linux/kref.h

+10 −18
Original line number Diff line number Diff line
@@ -44,57 +44,49 @@ static inline void kref_get(struct kref *kref) 
}



/**

 * kref_put - decrement refcount for object.

 * 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.

 *

 * Decrement the refcount, and if 0, call release().

 * 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_put(struct kref *kref, void (*release)(struct kref *kref))

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_dec_and_test(&kref->refcount)) {

	if (atomic_sub_and_test((int) count, &kref->refcount)) {

		release(kref);

		return 1;

	}

	return 0;

}





/**

 * kref_sub - subtract a number of refcounts for object.

 * kref_put - decrement refcount 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().

 * 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_sub(struct kref *kref, unsigned int count,

	     void (*release)(struct kref *kref))

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_sub_and_test((int) count, &kref->refcount)) {

		release(kref);

		return 1;

	}

	return 0;

	return kref_sub(kref, 1, release);

}

#endif /* _KREF_H_ */