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locking/atomic, kref: Kill kref_sub()

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By general sentiment kref_sub() is a bad interface, make it go away.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2016-11-14 17:34:19 +01:00 • committed by Ingo Molnar
parent 2c935bc572
commit bdfafc4ffd
6 changed files with 39 additions and 115 deletions
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38
include/linux/kref.h
View file

@ -53,36 +53,6 @@ static inline void kref_get(struct kref *kref)
WARN_ON_ONCE(atomic_inc_return(&kref->refcount) < 2);
}
/**
* 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.
@ -102,7 +72,13 @@ static inline int kref_sub(struct kref *kref, unsigned int count,
*/
static inline int kref_put(struct kref *kref, void (*release)(struct kref *kref))
{
return kref_sub(kref, 1, release);
WARN_ON(release == NULL);
if (atomic_dec_and_test(&kref->refcount)) {
release(kref);
return 1;
}
return 0;
}
static inline int kref_put_mutex(struct kref *kref,