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