[PATCH 4.4 01/28] kobject: Export kobject_get_unless_zero()

Greg Kroah-Hartman
2020-01-14T10:12:28Z

From: Jan Kara <jack@suse.cz>

commit c70c176ff8c3ff0ac6ef9a831cd591ea9a66bd1a upstream.

Make the function available for outside use and fortify it against NULL
kobject.

CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
include/linux/kobject.h | 2 ++
lib/kobject.c | 5 ++++-
2 files changed, 6 insertions(+), 1 deletion(-)

--- a/include/linux/kobject.h
+++ b/include/linux/kobject.h
@@ -108,6 +108,8 @@ extern int __must_check kobject_rename(s
extern int __must_check kobject_move(struct kobject *, struct kobject *);

extern struct kobject *kobject_get(struct kobject *kobj);
+extern struct kobject * __must_check kobject_get_unless_zero(
+ struct kobject *kobj);
extern void kobject_put(struct kobject *kobj);

extern const void *kobject_namespace(struct kobject *kobj);
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -599,12 +599,15 @@ struct kobject *kobject_get(struct kobje
}
EXPORT_SYMBOL(kobject_get);

-static struct kobject * __must_check kobject_get_unless_zero(struct kobject *kobj)
+struct kobject * __must_check kobject_get_unless_zero(struct kobject *kobj)
{
+ if (!kobj)
+ return NULL;
if (!kref_get_unless_zero(&kobj->kref))
kobj = NULL;
return kobj;
}
+EXPORT_SYMBOL(kobject_get_unless_zero);

/*
* kobject_cleanup - free kobject resources.