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Date: Wed, 4 Oct 2017 12:11:48 +0200
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Hans de Goede <hdegoede@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>, Arnd Bergmann <arnd@arndb.de>,
        Michael Thayer <michael.thayer@oracle.com>,
        "Knut St . Osmundsen" <knut.osmundsen@oracle.com>,
        Larry Finger <Larry.Finger@lwfinger.net>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] virt: Add vboxguest driver for Virtual Box Guest
 integration
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On Wed, Oct 04, 2017 at 11:32:23AM +0200, Hans de Goede wrote:
> Hi,
> 
> On 03-10-17 13:41, Hans de Goede wrote:
> 
> <snip>
> 
> > > > +#define CHECK_IOCTL_IN(req)                             \
> > > > +do {                                         \
> > > > +    if ((req)->Hdr.cbIn != (sizeof((req)->Hdr) + sizeof((req)->u.In)) || \
> > > > +        (req)->Hdr.cbOut != sizeof((req)->Hdr))                 \
> > > > +        return -EINVAL;                             \
> > > > +} while (0)
> > > 
> > > Make these things functions instead of macros.
> > 
> > Turning these into functions is a good idea I will do so for v2.
> 
> Correction, I forgot that the passed in "req" macro
> argument has a different type with all the calls, so
> these cannot be changed into functions because they
> rely on sizeof on the specific type to do the size
> checks.

Don't we already have built-in checks for these types of things?  Surely
we don't require each ioctl user in the kernel to do this by
themselves...

thanks,

greg k-h