sr_find_discipline
struct sr_discipline *sr_find_discipline(struct sr_softc *sc, const char *);
if (sd == NULL && (sd = sr_find_discipline(sc, bd->bd_dev)) == NULL) {
if (sd == NULL && (sd = sr_find_discipline(sc, bd->bd_dev)) == NULL) {
if (sd == NULL && (sd = sr_find_discipline(sc, bb->bb_dev)) == NULL) {