xbf_dma_alloc
if (xbf_dma_alloc(sc, &sc->sc_xr_dma, sc->sc_xr_size * PAGE_SIZE,
int xbf_dma_alloc(struct xbf_softc *, struct xbf_dma_mem *,
error = xbf_dma_alloc(sc, dma, size, size / PAGE_SIZE, mapflags);