On Tue, Apr 05, 2022 at 01:24:36PM +0300, Ilpo Järvinen wrote:
> After lookahead for XON/XOFF characters is added by the next
> patch, the receive side needs to ensure the flow-control
> actions are not retaken later on when those same characters
> get read by TTY.
>
> Thus, pass lookahead count to receive_buf and skip
> flow-control character actions if already taken for the
> character in question. Lookahead count will become live after
> the next patch.
...
> -static void n_tty_receive_char_special(struct tty_struct *tty, unsigned char c)
> +static void n_tty_receive_char_special(struct tty_struct *tty, unsigned char c,
> + bool lookahead_done)
> {
> struct n_tty_data *ldata = tty->disc_data;
>
> if (I_IXON(tty)) {
> if (c == START_CHAR(tty)) {
> - start_tty(tty);
> - process_echoes(tty);
> + if (!lookahead_done) {
> + start_tty(tty);
> + process_echoes(tty);
> + }
> return;
> }
> if (c == STOP_CHAR(tty)) {
> - stop_tty(tty);
> + if (!lookahead_done)
> + stop_tty(tty);
> return;
> }
Wouldn't be cleaner to inside out the conditionals?
> }
if (I_IXON(tty)) {
if (lookahead_done) {
// Can be joined, but I think this is better
if (c == START_CHAR(tty))
return;
if (c == STOP_CHAR(tty))
return;
} else {
if (c == START_CHAR(tty)) {
start_tty(tty);
process_echoes(tty);
return;
}
if (c == STOP_CHAR(tty)) {
stop_tty(tty);
return;
}
}
}
In my opinion this will show exactly what's going on when we have
lookahead_done and when not.
--
With Best Regards,
Andy Shevchenko
