kobject: kobj_type: remove default_attrs

Now that all in-kernel users of default_attrs for the kobj_type are gone
and converted to properly use the default_groups pointer instead, it can
be safely removed.

There is one standard way to create sysfs files in a kobj_type, and not
two like before, causing confusion as to which should be used.

Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/20220106133151.607703-1-gregkh@linuxfoundation.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/sysfs/file.c

@@ -703,19 +703,6 @@ int sysfs_change_owner(struct kobject *kobj, kuid_t kuid, kgid_t kgid)
 
 	ktype = get_ktype(kobj);
 	if (ktype) {
-		struct attribute **kattr;
-
-		/*
-		 * Change owner of the default attributes associated with the
-		 * ktype of @kobj.
-		 */
-		for (kattr = ktype->default_attrs; kattr && *kattr; kattr++) {
-			error = sysfs_file_change_owner(kobj, (*kattr)->name,
-							kuid, kgid);
-			if (error)
-				return error;
-		}
-
 		/*
 		 * Change owner of the default groups associated with the
 		 * ktype of @kobj.

include/linux/kobject.h

@@ -120,7 +120,6 @@ extern char *kobject_get_path(struct kobject *kobj, gfp_t flag);
 struct kobj_type {
 	void (*release)(struct kobject *kobj);
 	const struct sysfs_ops *sysfs_ops;
-	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);

lib/kobject.c

@@ -54,32 +54,6 @@ void kobject_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
 		kobj->ktype->get_ownership(kobj, uid, gid);
 }
 
-/*
- * populate_dir - populate directory with attributes.
- * @kobj: object we're working on.
- *
- * Most subsystems have a set of default attributes that are associated
- * with an object that registers with them.  This is a helper called during
- * object registration that loops through the default attributes of the
- * subsystem and creates attributes files for them in sysfs.
- */
-static int populate_dir(struct kobject *kobj)
-{
-	const struct kobj_type *t = get_ktype(kobj);
-	struct attribute *attr;
-	int error = 0;
-	int i;
-
-	if (t && t->default_attrs) {
-		for (i = 0; (attr = t->default_attrs[i]) != NULL; i++) {
-			error = sysfs_create_file(kobj, attr);
-			if (error)
-				break;
-		}
-	}
-	return error;
-}
-
 static int create_dir(struct kobject *kobj)
 {
 	const struct kobj_type *ktype = get_ktype(kobj);
@@ -90,12 +64,6 @@ static int create_dir(struct kobject *kobj)
 	if (error)
 		return error;
 
-	error = populate_dir(kobj);
-	if (error) {
-		sysfs_remove_dir(kobj);
-		return error;
-	}
-
 	if (ktype) {
 		error = sysfs_create_groups(kobj, ktype->default_groups);
 		if (error) {