SLBUFSIZE
sc->sc_ep = kmalloc(SLBUFSIZE, M_DEVBUF, M_WAITOK);
sc->sc_buf = sc->sc_ep + SLBUFSIZE - SLRMAX;
if (sc->sc_mp < sc->sc_ep + SLBUFSIZE) {
sc->sc_mp = sc->sc_buf = sc->sc_ep + SLBUFSIZE - SLRMAX;