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