drbd_interval_empty
if (drbd_interval_empty(this))
D_ASSERT(device, drbd_interval_empty(&peer_req->i));
D_ASSERT(device, !drbd_interval_empty(&peer_req->i));
D_ASSERT(device, drbd_interval_empty(&peer_req->i));
D_ASSERT(device, drbd_interval_empty(&peer_req->i));
D_ASSERT(device, drbd_interval_empty(&req->i));
D_ASSERT(device, drbd_interval_empty(&req->i));
if (!drbd_interval_empty(&req->i)) {