Re: [PATCH] n_tty: Ensure reader restarts worker for next reader

[Linus Torvalds]

Greg,
 what happened to this patch? Is it still waiting in some random tree
of yours, or did it get lost?

                    Linus

On Thu, Nov 7, 2013 at 10:59 AM, Peter Hurley <peter@xxxxxxxxxxxxxxxxxx> wrote:
> A departing reader must restart a flush_to_ldisc() worker _before_
> the next reader enters the read loop; this is to avoid the new reader
> concluding no more i/o is available and prematurely exiting, when the
> old reader simply hasn't re-started the worker yet.
>
> Cc: stable@xxxxxxxxxx # 3.12
> Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
> ---
>  drivers/tty/n_tty.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
> index 7a744b6..ce11cd5 100644
> --- a/drivers/tty/n_tty.c
> +++ b/drivers/tty/n_tty.c
> @@ -2250,6 +2250,9 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
>                 if (time)
>                         timeout = time;
>         }
> +       n_tty_set_room(tty);
> +       up_read(&tty->termios_rwsem);
> +
>         mutex_unlock(&ldata->atomic_read_lock);
>         remove_wait_queue(&tty->read_wait, &wait);
>
> @@ -2260,8 +2263,6 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
>         if (b - buf)
>                 retval = b - buf;
>
> -       n_tty_set_room(tty);
> -       up_read(&tty->termios_rwsem);
>         return retval;
>  }
>
> --
> 1.8.1.2
>
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