kfifo_out_peek
ret = kfifo_out_peek(seqno_fifo, seqno, sizeof(*seqno));
send_size = kfifo_out_peek(&gb_tty->write_fifo,
count = kfifo_out_peek(&tport->xmit_fifo, dmatx->buf, count);
data_count = kfifo_out_peek(&tport->xmit_fifo, icom_port->xmit_buf,
count = kfifo_out_peek(&tport->xmit_fifo, &stm32port->tx_buf[0],
ret = kfifo_out_peek(&test, buf, sizeof(buf));