B_BC
SET(bp->b_flags, B_BC);
KASSERT(ISSET(bp->b_flags, B_BC));
KASSERT(ISSET(bp->b_flags, B_BC));
KASSERT(ISSET(bp->b_flags, B_BC));
KASSERT(ISSET(bp->b_flags, B_BC));
if ((ISSET(bp->b_flags, B_BC)) && (!ISSET(bp->b_flags, B_DMA)))