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From:   Ajay Garg <ajaygargnsit@gmail.com>
Date:   Mon, 8 Nov 2021 14:25:31 +0530
Message-ID: <CAHP4M8XWbxVDAeN=4YGX93gNLDDWE0GS8_sKkNv2p_-yBjjHVg@mail.gmail.com>
Subject: Re: [PATCH v4] tty: vt: keyboard: add default switch-case, to handle
 smatch-warnings in method vt_do_kdgkb_ioctl
To:     Andy Shevchenko <andy.shevchenko@gmail.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jiri Slaby <jirislaby@kernel.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Emil Renner Berthing <kernel@esmil.dk>,
        "open list:SERIAL DRIVERS" <linux-serial@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Pavel Skripkin <paskripkin@gmail.com>
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> > This usually happens when switch has no default case and static
> > analyzers and even sometimes compilers can=E2=80=99t prove that all pos=
sible
> > values are covered.
> >
> >
>
> One blank line is enough.
>
> > Many thanks to the following for review of previous versions :
> >
> >         * Pavel Skripkin <paskripkin@gmail.com>
> >         * Andy Shevchenko <andy.shevchenko@gmail.com>
> >
> >
>
> Ditto for each such case.

Ok, will take care of this in all my future-patches.


>
> ...
>
> > +       default:
> > +               kbs =3D NULL;
>
> > +               ret =3D -ENOIOCTLCMD;
>
> Why is this? How is it supposed to work?

If there is no match for a cmd, causing the default-case to be hit, we
must return an error ret-code to the client.
The -ENOIOCTLCMD error ret-code has been chosen, on the same lines as
"vt_do_kdskled" method.


Thanks and Regards,
Ajay