mlx_ccb_map
rv = mlx_ccb_map(mlx, mc, data, datasize,
if ((rv = mlx_ccb_map(mlx, mc, result, 1024, MC_XFER_IN)) != 0)
if ((rv = mlx_ccb_map(mlx, mc, result, bufsize, MC_XFER_IN)) != 0)
rv = mlx_ccb_map(mlx, mc, kbuf, mu->mu_datasize, mu->mu_bufdir);
int mlx_ccb_map(struct mlx_softc *, struct mlx_ccb *, void *, int, int);