build_user_data
user_data = build_user_data(buf_idx, _IOC_NR(op), nr_elem, q_id, 0);
sqe->user_data = build_user_data(tag, ublksrv_get_op(iod), 0, q->q_id, 1);
sqe[0]->user_data = build_user_data(tag, ublk_op, 0, q->q_id, 1);
sqe[0]->user_data = build_user_data(tag, ublk_op, 1, q->q_id, 1);
sqe[0]->user_data = build_user_data(tag, ublk_op, 0, q->q_id, 1);
sqe[0]->user_data = build_user_data(tag,
sqe[1]->user_data = build_user_data(tag, ublk_op, 0, q->q_id, 1);
sqe[2]->user_data = build_user_data(tag, ublk_cmd_op_nr(sqe[2]->cmd_op), 0, q->q_id, 1);
user_data = build_user_data(io->tag, _IOC_NR(cmd_op), 0, q->q_id, 0);
sqe->user_data = build_user_data(tag, ublk_op, 0, q_id, 1);
sqe[0]->user_data = build_user_data(tag,
sqe[2]->user_data = build_user_data(tag, ublk_cmd_op_nr(sqe[2]->cmd_op), 0, q->q_id, 1);
sqe[0]->user_data = build_user_data(tag,
sqe[i]->user_data = build_user_data(tag, ublksrv_get_op(iod), i - zc, q->q_id, 1);
unreg->user_data = build_user_data(
sqe[i]->user_data = build_user_data(tag, UBLK_IO_OP_FLUSH, 0, q->q_id, 1);