Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 2d864e41 authored by Anatol Pomozov's avatar Anatol Pomozov Committed by Linus Torvalds
Browse files

kref: minor cleanup 

 - make warning smp-safe
 - result of atomic _unless_zero functions should be checked by caller
   to avoid use-after-free error
 - trivial whitespace fix.

Link: https://lkml.org/lkml/2013/4/12/391



Tested: compile x86, boot machine and run xfstests
Signed-off-by: default avatarAnatol Pomozov <anatol.pomozov@gmail.com>
[ Removed line-break, changed to use WARN_ON_ONCE()  - Linus ]
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 292088ee

include/linux/kref.h

+6 −3
Original line number Diff line number Diff line
@@ -39,8 +39,11 @@ static inline void kref_init(struct kref *kref) 
 */

static inline void kref_get(struct kref *kref)

{

	WARN_ON(!atomic_read(&kref->refcount));

	atomic_inc(&kref->refcount);

	/* If refcount was 0 before incrementing then we have a race

	 * condition when this kref is freeing by some other thread right now.

	 * In this case one should use kref_get_unless_zero()

	 */

	WARN_ON_ONCE(atomic_inc_return(&kref->refcount) < 2);

}



/**

lib/kobject.c

+1 −1
Original line number Diff line number Diff line
@@ -529,7 +529,7 @@ struct kobject *kobject_get(struct kobject *kobj) 
	return kobj;

}



static struct kobject *kobject_get_unless_zero(struct kobject *kobj)

static struct kobject * __must_check kobject_get_unless_zero(struct kobject *kobj)

{

	if (!kref_get_unless_zero(&kobj->kref))

		kobj = NULL;