PARF_OREAD
sc->sc_flags |= PARF_OREAD;
sc->sc_flags &= ~(PARF_OPEN|PARF_OREAD|PARF_OWRITE);
if (!!(sc->sc_flags & PARF_OREAD) ^ (uio->uio_rw == UIO_READ))
if (!!(sc->sc_flags & PARF_OREAD) ^ (uio->uio_rw == UIO_READ))