Commit 0a13cd1a authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

locking/atomic, kref: Implement kref_put_lock() 



Because home-rolling your own is _awesome_, stop doing it. Provide
kref_put_lock(), just like kref_put_mutex() but for a spinlock.

Signed-off-by: default avatarPeter 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: default avatarIngo Molnar <mingo@kernel.org>
parent 23b19ec3

include/linux/kref.h

+16 −6
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <linux/atomic.h>

#include <linux/kernel.h>

#include <linux/mutex.h>

#include <linux/spinlock.h>



struct kref {

	atomic_t refcount;
@@ -86,12 +87,21 @@ static inline int kref_put_mutex(struct kref *kref, 
				 struct mutex *lock)

{

	WARN_ON(release == NULL);

	if (unlikely(!atomic_add_unless(&kref->refcount, -1, 1))) {

		mutex_lock(lock);

		if (unlikely(!atomic_dec_and_test(&kref->refcount))) {

			mutex_unlock(lock);



	if (atomic_dec_and_mutex_lock(&kref->refcount, lock)) {

		release(kref);

		return 1;

	}

	return 0;

}



static inline int kref_put_lock(struct kref *kref,

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

				spinlock_t *lock)

{

	WARN_ON(release == NULL);



	if (atomic_dec_and_lock(&kref->refcount, lock)) {

		release(kref);

		return 1;

	}

net/sunrpc/svcauth.c

+10 −5
Original line number Diff line number Diff line
@@ -126,13 +126,18 @@ EXPORT_SYMBOL_GPL(svc_auth_unregister); 
static struct hlist_head	auth_domain_table[DN_HASHMAX];

static DEFINE_SPINLOCK(auth_domain_lock);



void auth_domain_put(struct auth_domain *dom)

static void auth_domain_release(struct kref *kref)

{

	if (atomic_dec_and_lock(&dom->ref.refcount, &auth_domain_lock)) {

	struct auth_domain *dom = container_of(kref, struct auth_domain, ref);



	hlist_del(&dom->hash);

	dom->flavour->domain_release(dom);

	spin_unlock(&auth_domain_lock);

}



void auth_domain_put(struct auth_domain *dom)

{

	kref_put_lock(&dom->ref, auth_domain_release, &auth_domain_lock);

}

EXPORT_SYMBOL_GPL(auth_domain_put);

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