Re: [PATCH] n_tty: Fix poll() when TIME_CHAR and MIN_CHAR == 0

From: Eric Dumazet
Date: Tue Feb 11 2014 - 13:33:03 EST


On Tue, 2014-02-11 at 11:49 -0500, Peter Hurley wrote:

> From: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
> Date: Tue, 11 Feb 2014 10:10:07 -0500
> Subject: [PATCH] n_tty: Fix poll() when TIME_CHAR and MIN_CHAR == 0
>
> Commit eafbe67f84761d787802e5113d895a316b6292fe,
> n_tty: Refactor input_available_p() by call site
> broke poll() when TIME_CHAR(tty) and MIN_CHAR(tty) are both 0.
>
> When TIME_CHAR and MIN_CHAR are both 0, input is available if the
> read_cnt is 1 (not 0).
>
> Reported-by: Stephane Eranian <eranian@xxxxxxxxxx>
> Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/tty/n_tty.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
> index cb8017a..2747a3b 100644
> --- a/drivers/tty/n_tty.c
> +++ b/drivers/tty/n_tty.c
> @@ -1896,7 +1896,7 @@ err:
> static inline int input_available_p(struct tty_struct *tty, int poll)
> {
> struct n_tty_data *ldata = tty->disc_data;
> - int amt = poll && !TIME_CHAR(tty) ? MIN_CHAR(tty) : 1;
> + int amt = poll && !TIME_CHAR(tty) && MIN_CHAR(tty) ? MIN_CHAR(tty) : 1;
>
> if (ldata->icanon && !L_EXTPROC(tty)) {
> if (ldata->canon_head != ldata->read_tail)

Reported-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Tested-by: Eric Dumazet <edumazet@xxxxxxxxxx>

Thanks guys


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