RDF_SEEK
sc->sc_flags &= ~RDF_SEEK;
if ((sc->sc_flags & RDF_SEEK) != 0) {
sc->sc_flags &= ~RDF_SEEK;
sc->sc_flags |= RDF_SEEK;
sc->sc_flags |= RDF_SEEK;
sc->sc_flags &= ~RDF_SEEK;
if (sc->sc_flags & RDF_SEEK) {
sc->sc_flags &= ~RDF_SEEK;