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SubjectRe: [PATCH v2 1/3] tty: Add functions for handling flow control chars
On Fri, Apr 08, 2022 at 02:39:52PM +0300, Ilpo Järvinen wrote:
> Move receive path flow control character handling to own function
> and a helper.
>
> This seems cleanest approach especially once skipping due to lookahead
> is added. Its downside is the duplicated START_CHAR and STOP_CHAR
> checks.
>
> No functional changes.

But it seems the change. See below.

...

> +static bool n_tty_is_char_flow_ctrl(struct tty_struct *tty, unsigned char c)
> +{
> + return c == START_CHAR(tty) || c == STOP_CHAR(tty);
> +}
> +
> +/* Returns true if c is consumed as flow-control character */
> +static bool n_tty_receive_char_flow_ctrl(struct tty_struct *tty, unsigned char c)
> +{
> + if (!n_tty_is_char_flow_ctrl(tty, c))
> + return false;
> +
> + if (c == START_CHAR(tty)) {
> + start_tty(tty);
> + process_echoes(tty);

> + } else if (c == STOP_CHAR(tty)) {

In the original code no 'else' was present.

Perhaps it's not a functional change, but this detail has to be explained.

> + stop_tty(tty);
> + }
> +
> + return true;
> +}

...

> - if (I_IXON(tty)) {
> - if (c == START_CHAR(tty)) {
> - start_tty(tty);
> - process_echoes(tty);
> - return;
> - }
> - if (c == STOP_CHAR(tty)) {
> - stop_tty(tty);
> - return;
> - }
> - }
> + if (I_IXON(tty) && n_tty_receive_char_flow_ctrl(tty, c))
> + return;

--
With Best Regards,
Andy Shevchenko


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