linux-kernel - Re: [PATCH v4 12/12] RFC: watchdog: export core symbols in WATCHDOG

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Date:   Wed, 4 Sep 2019 17:45:45 +0900
From:   Masahiro Yamada <yamada.masahiro@...ionext.com>
To:     Guenter Roeck <linux@...ck-us.net>
Cc:     Matthias Maennich <maennich@...gle.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "Cc: Android Kernel" <kernel-team@...roid.com>,
        Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jessica Yu <jeyu@...nel.org>,
        "Joel Fernandes (Google)" <joel@...lfernandes.org>,
        Lucas De Marchi <lucas.de.marchi@...il.com>,
        maco@...roid.com, sspatil@...gle.com,
        Will Deacon <will@...nel.org>,
        Linux Kbuild mailing list <linux-kbuild@...r.kernel.org>,
        linux-modules@...r.kernel.org,
        linux-usb <linux-usb@...r.kernel.org>,
        usb-storage@...ts.one-eyed-alien.net,
        linux-watchdog@...r.kernel.org
Subject: Re: [PATCH v4 12/12] RFC: watchdog: export core symbols in
 WATCHDOG_CORE namespace

On Wed, Sep 4, 2019 at 1:10 AM Guenter Roeck <linux@...ck-us.net> wrote:
>
> On Tue, Sep 03, 2019 at 04:06:38PM +0100, Matthias Maennich wrote:
> > Modules using symbols from the WATCHDOG_CORE namespace are required to
> > explicitly import the namespace. This patch was generated with the
> > following steps and serves as a reference to use the symbol namespace
> > feature:
> >
> >  1) Use EXPORT_SYMBOL_NS* macros instead of EXPORT_SYMBOL* for symbols
> >     in watchdog_core.c
> >  2) make  (see warnings during modpost about missing imports)
> >  3) make nsdeps
> >
> > I used 'allmodconfig' for the above steps to ensure all occurrences are
> > patched.
> >
> > Defining DEFAULT_SYMBOL_NAMESPACE in the Makefile is not trivial in this
> > case as not only watchdog_core is defined in drivers/watchdog/Makefile.
> > Hence this patch uses the variant of using the EXPORT_SYMBOL_NS* macros
> > to export into a different namespace.
> >
> > An alternative to this patch would be a single definition line before
> > any use of EXPORT_SYMBOL*:
> >  #define DEFAULT_SYMBOL_NAMESPACE WATCHDOG_CORE
> >
> > This patch serves as a reference on how to use the symbol namespaces.
> >
> > Reviewed-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> > Signed-off-by: Matthias Maennich <maennich@...gle.com>
>
> As mentioned before, I am opposed to this set of changes. I don't see
> the point of restricting the use of exported symbols in WATCHDOG_CORE.
>
> Guenter


I agree.

I do not like this patch set either.

Anyway, the last two patches (usb-stroage, watchdog)
are useful to demonstrate
that this has a bad taste.


--
Best Regards
Masahiro Yamada