From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Arnd Bergmann <arnd@kernel.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>,
Arnd Bergmann <arnd@arndb.de>,
linux-modules@vger.kernel.org,
"Rafael J. Wysocki" <rafael@kernel.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] module: silence warning about unused 'no_warn' variable
Date: Fri, 22 Mar 2024 14:47:03 +0100 [thread overview]
Message-ID: <2024032224-equator-calm-5f3a@gregkh> (raw)
In-Reply-To: <20240322132014.906097-1-arnd@kernel.org>
On Fri, Mar 22, 2024 at 02:20:05PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> The sysfs_create_link() return code is marked as __must_check, but the
> module_add_driver() function tries hard to not care, by assigning the
> return code to a variable. When building with 'make W=1', gcc still
> warns because this variable is only assigned but not used:
>
> drivers/base/module.c: In function 'module_add_driver':
> drivers/base/module.c:36:6: warning: variable 'no_warn' set but not used [-Wunused-but-set-variable]
>
> Add an explicit cast to void to prevent this check as well.
>
> Cc: Luis Chamberlain <mcgrof@kernel.org>
> Cc: linux-modules@vger.kernel.org
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> Fixes: e17e0f51aeea ("Driver core: show drivers in /sys/module/")
> See-also: 4a7fb6363f2d ("add __must_check to device management code")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> I'm not entirely sure what bug the __must_check on sysfs_create_link()
> is trying to prevent, or why the module loader code is allowed to
> ignore this. It would be nice to have an Ack from the sysfs maintainers
> on this.
No, let's fix this properly and unwind if we can't create the link. You
are pointing at something from 2006, so I guess we always thought "this
can not fail" and never did anything about it since then.
thanks,
greg k-h
prev parent reply other threads:[~2024-03-22 13:47 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-22 13:20 [PATCH] module: silence warning about unused 'no_warn' variable Arnd Bergmann
2024-03-22 13:47 ` Greg Kroah-Hartman [this message]
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