S_RING_BLOCK
if (sringp->s_ring_state & S_RING_BLOCK) {
sringp->s_ring_state &= ~S_RING_BLOCK;
if (ringp->s_ring_state & (S_RING_BLOCK | S_RING_PROC)) {
(ringp->s_ring_state & (S_RING_BLOCK|S_RING_BLANK))) &&
ringp->s_ring_state |= S_RING_BLOCK;