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Commit c25d1dfb authored by Robin Holt's avatar Robin Holt Committed by Greg Kroah-Hartman
Browse files

kobject: Introduce kset_find_obj_hinted. 



One call chain getting to kset_find_obj is:
  link_mem_sections()
    find_mem_section()
      kset_find_obj()

This is done during boot.  The memory sections were added in a linearly
increasing order and link_mem_sections tends to utilize them in that
same linear order.

Introduce a kset_find_obj_hinted which is passed the result of the
previous kset_find_obj which it uses for a quick "is the next object
our desired object" check before falling back to the old behavior.

Signed-off-by: default avatarRobin Holt <holt@sgi.com>
To: Robert P. J. Day <rpjday@crashcourse.ca>
Reviewed-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent ead454fe

include/linux/kobject.h

+2 −0
Original line number Diff line number Diff line
@@ -191,6 +191,8 @@ static inline struct kobj_type *get_ktype(struct kobject *kobj) 
}



extern struct kobject *kset_find_obj(struct kset *, const char *);

extern struct kobject *kset_find_obj_hinted(struct kset *, const char *,

						struct kobject *);



/* The global /sys/kernel/ kobject for people to chain off of */

extern struct kobject *kernel_kobj;

lib/kobject.c

+39 −0
Original line number Diff line number Diff line
@@ -745,18 +745,57 @@ void kset_unregister(struct kset *k) 
 * take a reference and return the object.

 */

struct kobject *kset_find_obj(struct kset *kset, const char *name)

{

	return kset_find_obj_hinted(kset, name, NULL);

}



/**

 * kset_find_obj_hinted - search for object in kset given a predecessor hint.

 * @kset: kset we're looking in.

 * @name: object's name.

 * @hint: hint to possible object's predecessor.

 *

 * Check the hint's next object and if it is a match return it directly,

 * otherwise, fall back to the behavior of kset_find_obj().  Either way

 * a reference for the returned object is held and the reference on the

 * hinted object is released.

 */

struct kobject *kset_find_obj_hinted(struct kset *kset, const char *name,

				     struct kobject *hint)

{

	struct kobject *k;

	struct kobject *ret = NULL;



	spin_lock(&kset->list_lock);



	if (!hint)

		goto slow_search;



	/* end of list detection */

	if (hint->entry.next == kset->list.next)

		goto slow_search;



	k = container_of(hint->entry.next, struct kobject, entry);

	if (!kobject_name(k) || strcmp(kobject_name(k), name))

		goto slow_search;



	ret = kobject_get(k);

	goto unlock_exit;



slow_search:

	list_for_each_entry(k, &kset->list, entry) {

		if (kobject_name(k) && !strcmp(kobject_name(k), name)) {

			ret = kobject_get(k);

			break;

		}

	}



unlock_exit:

	spin_unlock(&kset->list_lock);



	if (hint)

		kobject_put(hint);



	return ret;

}