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

[David Ahern <dsahern@gmail.com>]

On 2/11/14, 9:49 AM, Peter Hurley wrote:
> From: Peter Hurley <peter@hurleysoftware.com>
> 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@google.com>
> Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
> ---
>   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)
>

Worked for me.

Tested-by: David Ahern <dsahern@gmail.com>