From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: kernel test robot <lkp@intel.com>,
Nick Desaulniers <nick.desaulniers@gmail.com>,
clang-built-linux <clang-built-linux@googlegroups.com>,
kbuild-all@lists.01.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Thomas Zimmermann <tzimmermann@suse.de>,
Petr Mladek <pmladek@suse.com>
Subject: Re: drivers/media/v4l2-core/v4l2-ioctl.c:303:28: warning: taking address of packed member 'pixelformat' of class or structure 'v4l2_pix_format_mplane' may result in an unaligned pointer value
Date: Fri, 16 Jul 2021 15:12:11 +0300 [thread overview]
Message-ID: <YPF3m01nYlt3On7V@smile.fi.intel.com> (raw)
In-Reply-To: <20210716114105.GF3@paasikivi.fi.intel.com>
On Fri, Jul 16, 2021 at 02:41:05PM +0300, Sakari Ailus wrote:
> On Wed, Jul 14, 2021 at 10:45:26PM +0300, Andy Shevchenko wrote:
> > > >> drivers/media/v4l2-core/v4l2-ioctl.c:347:37: warning: taking address of packed member 'pixelformat' of class or structure 'v4l2_sdr_format' may result in an unaligned pointer value [-Waddress-of-packed-member]
> >
> > Why is it packed in the first place? Is it used on unaligned addresses
> > in other structures? But even so, why should it matter?
>
> It's packed since we wanted to avoid having holes in the structs. There are
> other ways to do that but it's ABI dependent and is prone to human errors,
> too.
What holes can you think about in the above mention structure?
In case if you are going to extend it you will need anyway changes somewhere
else as well.
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2021-07-16 12:12 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-14 17:55 drivers/media/v4l2-core/v4l2-ioctl.c:303:28: warning: taking address of packed member 'pixelformat' of class or structure 'v4l2_pix_format_mplane' may result in an unaligned pointer value kernel test robot
2021-07-14 19:45 ` Andy Shevchenko
2021-07-16 11:41 ` Sakari Ailus
2021-07-16 12:12 ` Andy Shevchenko [this message]
2021-08-19 8:10 ` Sakari Ailus
2021-08-26 13:22 ` Petr Mladek
2021-11-04 22:21 kernel test robot
2021-11-05 10:21 ` Andy Shevchenko
2022-01-08 10:33 kernel test robot
2022-01-09 14:26 ` Andy Shevchenko
2022-01-10 19:44 ` Nick Desaulniers
2022-01-10 20:49 ` Andy Shevchenko
2022-01-10 21:22 ` Nick Desaulniers
2022-01-17 3:40 kernel test robot
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