control_data
sizeof(struct control_data));
#define SCX_CDOFF(x) offsetof(struct control_data, x)
struct control_data *sc_control_data;
sizeof(struct control_data), PAGE_SIZE, 0, &seg, 1, &nseg, 0);
sizeof(struct control_data), (void **)&sc->sc_control_data,
sizeof(struct control_data), 1,
sizeof(struct control_data), 0, 0, &sc->sc_cddmamap);
sc->sc_control_data, sizeof(struct control_data), NULL, 0);