Re: [PATCH] watchdog: core: Make use of devm_register_reboot_notifier()

[Guenter Roeck]

On 04/04/2017 08:47 AM, Andy Shevchenko wrote:
> On Tue, Apr 4, 2017 at 5:10 PM, Andrey Smirnov <andrew.smirnov@xxxxxxxxx> wrote:
> > Save a bit of cleanup code by leveraging newly added
> > devm_register_reboot_notifier().
>
> > @@ -247,7 +247,8 @@ static int __watchdog_register_device(struct watchdog_device *wdd)
> >         if (test_bit(WDOG_STOP_ON_REBOOT, &wdd->status)) {
> >                 wdd->reboot_nb.notifier_call = watchdog_reboot_notifier;
> >
> > -               ret = register_reboot_notifier(&wdd->reboot_nb);
>
> > +               ret = devm_register_reboot_notifier(wdd->parent,
> > +                                                   &wdd->reboot_nb);
>
> I'm not sure it's logically correct. Perhaps binding to the actual
> watchdog device would be better.
> Though, Guenter can correct me.

As mentioned in my other reply, it doesn't work since wdd->parent can be NULL.
It might be possible to move the code into watchdog_dev_register() and tie it
to the watchdog device, but I have not explored what that would require.

Guenter

> Could it be one line after all?
>
> >                 if (ret) {
> >                         pr_err("watchdog%d: Cannot register reboot notifier (%d)\n",
> >                                wdd->id, ret);
> > @@ -302,9 +303,6 @@ static void __watchdog_unregister_device(struct watchdog_device *wdd)
> >         if (wdd->ops->restart)
> >                 unregister_restart_handler(&wdd->restart_nb);
> >
> > -       if (test_bit(WDOG_STOP_ON_REBOOT, &wdd->status))
> > -               unregister_reboot_notifier(&wdd->reboot_nb);
> > -