Re: [bug report] usb: gadget: u_serial: process RX in workqueue instead of tasklet

[mirq-linux@rere.qmqm.pl]

On Mon, Jun 24, 2019 at 03:32:58PM +0300, Dan Carpenter wrote:
> Hello Michał Mirosław,
> 
> This is a semi-automatic email about new static checker warnings.
> 
> The patch 8b4c62aef6f6: "usb: gadget: u_serial: process RX in
> workqueue instead of tasklet" from Dec 16, 2018, leads to the
> following Smatch complaint:
[...] 
>    431		/* We want our data queue to become empty ASAP, keeping data
>    432		 * in the tty and ldisc (not here).  If we couldn't push any
>    433		 * this time around, RX may be starved, so wait until next jiffy.
>    434		 *
>    435		 * We may leave non-empty queue only when there is a tty, and
>    436		 * either it is throttled or there is no more room in flip buffer.
>    437		 */
>    438		if (!list_empty(queue) && !tty_throttled(tty))
>                                           ^^^^^^^^^^^^^^^^^^^
> in the original code there was check for NULL here but the patch removed
> it.
> 
>    439			schedule_delayed_work(&port->push, 1);
>    440	

Hi Dan,

The code is correct and explained in the comment above it - while() loop
above can be exited before emptying the queue only when tty != NULL.

Best Regards,
Michał Mirosław