Re: [PATCH -next] applicom: fix some err codes returned by ac_ioctl

[gregkh <gregkh@linuxfoundation.org>]

On Wed, Mar 24, 2021 at 01:03:50PM +0100, Arnd Bergmann wrote:
> On Wed, Mar 24, 2021 at 8:20 AM Xu Jia <xujia39@huawei.com> wrote:
> >
> > When cmd > 6 or copy_to_user() fail, The variable 'ret' would not be
> > returned back. Fix the 'ret' set but not used.
> >
> > Signed-off-by: Xu Jia <xujia39@huawei.com>
> 
> Reviewed-by: Arnd Bergmann <arnd@arndb.de>
> 
> > diff --git a/drivers/char/applicom.c b/drivers/char/applicom.c
> > index 14b2d8034c51..0ab765143354 100644
> > --- a/drivers/char/applicom.c
> > +++ b/drivers/char/applicom.c
> > @@ -839,7 +839,7 @@ static long ac_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> >         Dummy = readb(apbs[IndexCard].RamIO + VERS);
> >         kfree(adgl);
> >         mutex_unlock(&ac_mutex);
> > -       return 0;
> > +       return ret;
> >
> 
> Apparently this has been broken since the driver was first merged in
> linux-2.3.16. I could find no indication of anyone using the driver
> and reporting any problems in the git history and it clearly still has
> the style of drivers writting in the 1990s. On the other hand, this is
> (was) used in some very long-lived systems and you can still
> buy old applicom cards from artisan[1].
> 
> Is there any chance this driver is still used anywhere with modern
> kernels? I suspect we could move it to staging to find out.

No objection from me to move it to staging, want to send a patch or I
can.

thanks,

greg k-h