diff --git a/drivers/md/dm-switch.c b/drivers/md/dm-switch.c
index fae35caf3672..8a0f057b8122 100644
--- a/drivers/md/dm-switch.c
+++ b/drivers/md/dm-switch.c
@@ -61,8 +61,7 @@ static struct switch_ctx *alloc_switch_ctx(struct dm_target *ti, unsigned nr_pat
 {
 	struct switch_ctx *sctx;
 
-	sctx = kzalloc(sizeof(struct switch_ctx) + nr_paths * sizeof(struct switch_path),
-		       GFP_KERNEL);
+	sctx = kzalloc(struct_size(sctx, path_list, nr_paths), GFP_KERNEL);
 	if (!sctx)
 		return NULL;