P_NEG_DREPLY
[P_NEG_DREPLY] = "NegDReply",
drbd_send_ack_rp(peer_device, P_NEG_DREPLY, p);
[P_NEG_DREPLY] = { sizeof(struct p_block_ack), got_NegDReply },
err = drbd_send_ack(peer_device, P_NEG_DREPLY, peer_req);