diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index af30cbe7a8ea..b477a8dc0020 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -1025,10 +1025,9 @@ static struct nd_region *nd_region_create(struct nvdimm_bus *nvdimm_bus,
 		}
 		region_buf = ndbr;
 	} else {
-		nd_region = kzalloc(sizeof(struct nd_region)
-				+ sizeof(struct nd_mapping)
-				* ndr_desc->num_mappings,
-				GFP_KERNEL);
+		nd_region = kzalloc(struct_size(nd_region, mapping,
+						ndr_desc->num_mappings),
+				    GFP_KERNEL);
 		region_buf = nd_region;
 	}