upcall_pid = dpif_linux_port_get_pid(dpif_, request.port_no);
request.upcall_pid = &upcall_pid;
error = dpif_linux_vport_transact(&request, &reply, &buf);
upcall_pid = dpif_linux_port_get_pid(dpif_, request.port_no);
request.upcall_pid = &upcall_pid;
error = dpif_linux_vport_transact(&request, &reply, &buf);