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: Robin Holt <holt@sgi.com>
To: Robert P. J. Day <rpjday@crashcourse.ca>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/include/linux/kobject.h b/include/linux/kobject.h
index 7950a37..8f6d121 100644
--- a/include/linux/kobject.h
+++ b/include/linux/kobject.h
@@ -191,6 +191,8 @@
}
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;
diff --git a/lib/kobject.c b/lib/kobject.c
index f07c572..82dc34c 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -746,17 +746,56 @@
*/
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;
}