mm/slab: create sysfs attribute through default_groups

The driver core can automatically create custom type attributes.
This makes the code and error-handling shorter.

Signed-off-by: Thomas Weißschuh <[email protected]>
Reviewed-by: Harry Yoo <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Vlastimil Babka (SUSE) <[email protected]>

Author: t-8ch

mm/slub.c

@@ -9317,9 +9317,7 @@ static struct attribute *slab_attrs[] = {
 	NULL
 };
 
-static const struct attribute_group slab_attr_group = {
-	.attrs = slab_attrs,
-};
+ATTRIBUTE_GROUPS(slab);
 
 static ssize_t slab_attr_show(struct kobject *kobj,
 				struct attribute *attr,
@@ -9366,6 +9364,7 @@ static const struct sysfs_ops slab_sysfs_ops = {
 static const struct kobj_type slab_ktype = {
 	.sysfs_ops = &slab_sysfs_ops,
 	.release = kmem_cache_release,
+	.default_groups = slab_groups,
 };
 
 static struct kset *slab_kset;
@@ -9453,10 +9452,6 @@ static int sysfs_slab_add(struct kmem_cache *s)
 	if (err)
 		goto out;
 
-	err = sysfs_create_group(&s->kobj, &slab_attr_group);
-	if (err)
-		goto out_del_kobj;
-
 	if (!unmergeable) {
 		/* Setup first alias */
 		sysfs_slab_alias(s, s->name);
@@ -9465,9 +9460,6 @@ static int sysfs_slab_add(struct kmem_cache *s)
 	if (!unmergeable)
 		kfree(name);
 	return err;
-out_del_kobj:
-	kobject_del(&s->kobj);
-	goto out;
 }
 
 void sysfs_slab_unlink(struct kmem_cache *s)