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From: Arnd Bergmann <arnd@arndb.de>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Subject: Re: [PATCH 2/3, RFC] watchdog dev BKL pushdown
Date: Tue, 20 May 2008 23:00:34 +0200
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On Tuesday 20 May 2008, Alan Cox wrote:
> Current patch (& example conversions) below.

Very nice code!

> +       if (w->ops->ioctl) {
> +               r = w->ops->ioctl(w, cmd, arg);
> +               if (r != -ENOIOCTLCMD)
> +                       return r;
> +       }

Are you planning this as a transitional method for
converting drivers, or are you aware of any driver that
actually needs its own ioctl method?

> +static const struct file_operations watchdog_fops = {
> +       .owner          = THIS_MODULE,
> +       .llseek         = no_llseek,
> +       .write          = watchdog_write,
> +       .unlocked_ioctl = watchdog_ioctl,
> +       .open           = watchdog_open,
> +       .release        = watchdog_release,
> +};

All the ioctl numbers are compatible, so it would be good
to register the watchdog ioctl function as compat_ioctl
as well. Once all drivers are using the common abstraction,
we can also kill their COMPATIBLE_IOCTL() entries in
fs/compat_ioctl.c.

> --- /dev/null
> +++ b/drivers/watchdog/watchdog.h

There are a few watchdog drivers living outside of drivers/watchdog/,
I could find:

* arch/um/drivers/harddog_kern.c
* drivers/char/ipmi/ipmi_watchdog.c
* drivers/rtc/rtc-m41t80.c
* drivers/s390/char/vmwatchdog.c
* drivers/sbus/char/cpwatchdog.c
* drivers/sbus/char/riowatchdog.c

In order to conver those to the new model, you either have to
move them to the right place, or move the new declarations to
include/linux/watchdog.h.

	Arnd <><