C_WRITE
sc->sc_ioc.cmd = C_WRITE;
sc->sc_ioc.c_cmd = (bp->b_flags & B_READ) != 0 ? C_READ : C_WRITE;
sc->sc_ioc.c_cmd = C_WRITE;
ct_ioc.cmd = C_WRITE;
rd_ioc.c_cmd = func == F_READ ? C_READ : C_WRITE;