kref: minor cleanup (2d864e41) · Commits · 戴 / test

- 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:

Anatol Pomozov <anatol.pomozov@gmail.com> [ Removed line-break, changed to use WARN_ON_ONCE() - Linus ] Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

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;

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