kobject: Add support for default attribute groups to kobj_type

kobj_type currently uses a list of individual attributes to store
default attributes. Attribute groups are more flexible than a list of
attributes because groups provide support for attribute visibility. So,
add support for default attribute groups to kobj_type.

In future patches, the existing uses of kobj_type’s attribute list will
be converted to attribute groups. When that is complete, kobj_type’s
attribute list, “default_attrs”, will be removed.

Signed-off-by: Kimberly Brown <kimbrownkd@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/kobject.h b/include/linux/kobject.h
index 1ab0d62..e2ca0a2 100644
--- a/include/linux/kobject.h
+++ b/include/linux/kobject.h
@@ -139,7 +139,8 @@
 struct kobj_type {
 	void (*release)(struct kobject *kobj);
 	const struct sysfs_ops *sysfs_ops;
-	struct attribute **default_attrs;
+	struct attribute **default_attrs;	/* use default_groups instead */
+	const struct attribute_group **default_groups;
 	const struct kobj_ns_type_operations *(*child_ns_type)(struct kobject *kobj);
 	const void *(*namespace)(struct kobject *kobj);
 	void (*get_ownership)(struct kobject *kobj, kuid_t *uid, kgid_t *gid);