Commit ec48c940 authored May 08, 2017 by Andi Kleen Committed by Linus Torvalds May 08, 2017

kref: remove WARN_ON for NULL release functions

The kref functions check for NULL release functions. This WARN_ON seems
rather pointless. We will eventually release and then just crash
nicely. It is also somewhat expensive because these functions are
inlined in a lot of places. Removing the WARN_ONs saves around 2.3k in
this kernel (likely more in others with more drivers)

text data bss dec hex filename
9083992 5367600 11116544 25568136 1862388 vmlinux-before-load-avg
9070166 5367600 11116544 25554310 185ed86 vmlinux-load-avg

Link: http://lkml.kernel.org/r/20170315021431.13107-5-andi@firstfloor.org

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent e6ccbff0

include/linux/kref.h

+0 −6

Original line number	Diff line number	Diff line
		@@ -66,8 +66,6 @@ static inline void kref_get(struct kref *kref)
		*/
		static inline int kref_put(struct kref kref, void (release)(struct kref *kref))
		{
		WARN_ON(release == NULL);

		if (refcount_dec_and_test(&kref->refcount)) {
		release(kref);
		return 1;
		@@ -79,8 +77,6 @@ static inline int kref_put_mutex(struct kref *kref,
		void (release)(struct kref kref),
		struct mutex *lock)
		{
		WARN_ON(release == NULL);

		if (refcount_dec_and_mutex_lock(&kref->refcount, lock)) {
		release(kref);
		return 1;
		@@ -92,8 +88,6 @@ static inline int kref_put_lock(struct kref *kref,
		void (release)(struct kref kref),
		spinlock_t *lock)
		{
		WARN_ON(release == NULL);

		if (refcount_dec_and_lock(&kref->refcount, lock)) {
		release(kref);
		return 1;