--- zzzz-none-000/linux-3.10.107/drivers/md/dm-cache-policy.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/drivers/md/dm-cache-policy.c	2021-02-04 17:41:59.000000000 +0000
@@ -119,13 +119,13 @@
 	type = get_policy(name);
 	if (!type) {
 		DMWARN("unknown policy type");
-		return NULL;
+		return ERR_PTR(-EINVAL);
 	}
 
 	p = type->create(cache_size, origin_size, cache_block_size);
 	if (!p) {
 		put_policy(type);
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 	}
 	p->private = type;
 
@@ -146,6 +146,10 @@
 {
 	struct dm_cache_policy_type *t = p->private;
 
+	/* if t->real is set then an alias was used (e.g. "default") */
+	if (t->real)
+		return t->real->name;
+
 	return t->name;
 }
 EXPORT_SYMBOL_GPL(dm_cache_policy_get_name);