diff --git a/drivers/rapidio/devices/rio_mport_cdev.c b/drivers/rapidio/devices/rio_mport_cdev.c
index 451608e960a1..3abbba8c2b5b 100644
--- a/drivers/rapidio/devices/rio_mport_cdev.c
+++ b/drivers/rapidio/devices/rio_mport_cdev.c
@@ -1710,8 +1710,7 @@ static int rio_mport_add_riodev(struct mport_cdev_priv *priv,
 	if (rval & RIO_PEF_SWITCH) {
 		rio_mport_read_config_32(mport, destid, hopcount,
 					 RIO_SWP_INFO_CAR, &swpinfo);
-		size += (RIO_GET_TOTAL_PORTS(swpinfo) *
-			 sizeof(rswitch->nextdev[0])) + sizeof(*rswitch);
+		size += struct_size(rswitch, nextdev, RIO_GET_TOTAL_PORTS(swpinfo));
 	}
 
 	rdev = kzalloc(size, GFP_KERNEL);