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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Fri, 18 Oct 2019 15:31:16 +0200
Message-ID: <CAK8P3a2V_xP44X-Y3Mx1jX_16wKbc+T_REUP-jzj8bxPMVnifQ@mail.gmail.com>
Subject: Re: [Y2038] [PATCH v6 31/43] compat_ioctl: move WDIOC handling into
 wdt drivers
To:     Ben Hutchings <ben.hutchings@codethink.co.uk>
Cc:     Al Viro <viro@zeniv.linux.org.uk>,
        y2038 Mailman List <y2038@lists.linaro.org>,
        Linux FS-devel Mailing List <linux-fsdevel@vger.kernel.org>,
        Guenter Roeck <linux@roeck-us.net>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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On Fri, Oct 18, 2019 at 2:49 PM Ben Hutchings
<ben.hutchings@codethink.co.uk> wrote:
>
> On Wed, 2019-10-09 at 21:10 +0200, Arnd Bergmann wrote:
> > All watchdog drivers implement the same set of ioctl commands, and
> > fortunately all of them are compatible between 32-bit and 64-bit
> > architectures.
> >
> > Modern drivers always go through drivers/watchdog/wdt.c as an abstraction
> > layer, but older ones implement their own file_operations on a character
> > device for this.
> >
> > Move the handling from fs/compat_ioctl.c into the individual drivers.
> >
> > Note that most of the legacy drivers will never be used on 64-bit
> > hardware, because they are for an old 32-bit SoC implementation, but
> > doing them all at once is safer than trying to guess which ones do
> > or do not need the compat_ioctl handling.
> >
> > Reviewed-by: Guenter Roeck <linux@roeck-us.net>
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> > ---
> >  arch/powerpc/platforms/52xx/mpc52xx_gpt.c |  1 +
> >  arch/um/drivers/harddog_kern.c            |  1 +
> >  drivers/char/ipmi/ipmi_watchdog.c         |  1 +
> >  drivers/hwmon/fschmd.c                    |  1 +
> >  drivers/rtc/rtc-ds1374.c                  |  1 +
> [...]
>
> It Looks like you missed a couple:
>
> drivers/rtc/rtc-m41t80.c

No idea how I missed this. Adding it now.

> drivers/watchdog/kempld_wdt.c

This one is covered: the watchdog_ops->ioctl is called by
the wdt_dev_ioctl() function as a fallback.

After checking once more, I did find another instance I missed
though: drivers/hwmon/w83793.c, I'm adding that as welll now.

m41t80 does not seem to have any 64-bit machines using it,
but w83793 does, and they clearly both should have been
changed.

Thanks for the review!

     Arnd