> > From: Daniel Starke <daniel.starke@xxxxxxxxxxx>
> >
> > The current implementation does not handle the situation that no data
> > is in the internal queue and needs to be sent out while the user tty
> > fifo is full.
> > Add a timer that moves more data from user tty down to the internal
> > queue which is then serialized on the ldisc. This timer is triggered
> > if no data was moved from a user tty to the internal queue within 10 * T1.
> >
> > Fixes: e1eaea46bb40 ("tty: n_gsm line discipline")
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Daniel Starke <daniel.starke@xxxxxxxxxxx>
> > ---
> > drivers/tty/n_gsm.c | 43 +++++++++++++++++++++++++++++++++++--------
> > 1 file changed, 35 insertions(+), 8 deletions(-)
> >
> > See patch 6 regarding changes since to v1.
> >
> > diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index
> > 0a9924445968..3a4a2394d970 100644
> > --- a/drivers/tty/n_gsm.c
> > +++ b/drivers/tty/n_gsm.c
> ...
> > @@ -833,6 +834,7 @@ static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
> > list_add_tail(&msg->list, &gsm->tx_list);
> > gsm->tx_bytes += msg->len;
> > gsm_data_kick(gsm, dlci);
> > + mod_timer(&gsm->kick_timer, jiffies + 10 * gsm->t1 * HZ / 100);
>
> The formula deserves an explanation. And why 10 * X / 100, and not X / 10?
T1 is defined as 1/100th of a second (see chapter 5.7.1 of the standard).
Therefore, it is gsm->t1 * HZ / 100. I chose 10x T1 as this case should
usually not occur and only acts as a final countermeasure against a
stalled link. Or are there any other suggestions for a proper kick timer
value?
> > @@ -1062,9 +1058,9 @@ static int gsm_dlci_modem_output(struct gsm_mux *gsm, struct gsm_dlci *dlci,
> > * renegotiate DLCI priorities with optional stuff. Needs optimising.
> > */
> >
> > -static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
> > +static int gsm_dlci_data_sweep(struct gsm_mux *gsm)
> > {
> > - int len;
> > + int len, ret = 0;
>
> Why is ret signed?
Many obviously only unsigned values are signed in the code of the original
author. I simply aligned my code to this to believe that int is preferred.
But I can change it to unsigned int if this is preferred here?
Best regards,
Daniel Starke
