MALO_BUSY
while (sc->sc_flags & MALO_BUSY)
sc->sc_flags |= MALO_BUSY;
sc->sc_flags &= ~MALO_BUSY;
while ((sc->sc_flags & MALO_BUSY) && error == 0)
sc->sc_flags |= MALO_BUSY;
sc->sc_flags &= ~MALO_BUSY;