Re: [RFC] QR encoding for Oops messages

["Teodora Băluţă" <teobaluta@gmail.com>]

On Wed, Mar 19, 2014 at 10:18 PM, Dave Jones <davej@redhat.com> wrote:
> On Mon, Mar 17, 2014 at 02:59:47PM -0700, Teodora Baluta wrote:
>  > This feature encodes Oops messages into a QR barcode that is scannable by
>  > any device with a camera.
>
>  ...
>
>  >  include/linux/print_oops.h |   11 +
>  >  include/linux/qrencode.h   |  546 +++++++++++++
>  >  kernel/Makefile            |    1 +
>  >  kernel/panic.c             |    5 +
>  >  kernel/print_oops.c        |  173 +++++
>  >  kernel/printk/printk.c     |    9 +-
>  >  lib/Kconfig                |    5 +
>  >  lib/Kconfig.debug          |   11 +
>  >  lib/Makefile               |    3 +
>  >  lib/qr/Makefile            |    6 +
>  >  lib/qr/bitstream.c         |  233 ++++++
>  >  lib/qr/bitstream.h         |   37 +
>  >  lib/qr/mask.c              |  320 ++++++++
>  >  lib/qr/mask.h              |   39 +
>  >  lib/qr/mmask.c             |  175 +++++
>  >  lib/qr/mmask.h             |   36 +
>  >  lib/qr/mqrspec.c           |  259 +++++++
>  >  lib/qr/mqrspec.h           |  155 ++++
>  >  lib/qr/qrencode.c          |  871 +++++++++++++++++++++
>  >  lib/qr/qrencode.h          |  546 +++++++++++++
>  >  lib/qr/qrinput.c           | 1834 ++++++++++++++++++++++++++++++++++++++++++++
>  >  lib/qr/qrinput.h           |  129 ++++
>  >  lib/qr/qrspec.c            |  543 +++++++++++++
>  >  lib/qr/qrspec.h            |  178 +++++
>  >  lib/qr/rscode.c            |  325 ++++++++
>  >  lib/qr/rscode.h            |   38 +
>  >  lib/qr/split.c             |  331 ++++++++
>  >  lib/qr/split.h             |   44 ++
>  >  28 files changed, 6860 insertions(+), 3 deletions(-)
>
> That's a ton of code we're adding into one of the most fragile parts of the kernel.
>
> A lot of what libqrencode does would seem to be superfluous to the requirements
> here, as we don't output kernel oopses in kanji for eg, and won't care about
> multiple versions of the qr spec.

That's true. I didn't do that much cleanup in the library afraid of
breaking something and focused that I get this done one way or
another. Indeed, the library is userspace and is made to be versatile
rather than small.

>
> How much of this could we drop ?

There are two things to do: remove all the other modes except binary
(kanji, numerical, etc.) and use the Reed Solomon encode/decode in the
lib/reed_solomon/ folder as not to have redundacy. So to say, quite a
lot.

Thanks,

-- 
Teodora

>
>         Dave
>