Re: [RFC PATCH 01/21] crypto: scomp - Revert "add support for deflate rfc1950 (zlib)"

Giovanni Cabiddu
2023-08-03T09:51:47Z

Hi Ard,

On Tue, Jul 18, 2023 at 01:58:27PM +0100, Ard Biesheuvel wrote:
> This reverts commit a368f43d6e3a001e684e9191a27df384fbff12f5.
>
> "zlib-deflate" was introduced 6 years ago, but it does not have any
> users. So let's remove the generic implementation and the test vectors,
> but retain the "zlib-deflate" entry in the testmgr code to avoid
> introducing warning messages on systems that implement zlib-deflate in
> hardware.
>
> Note that RFC 1950 which forms the basis of this algorithm dates back to
> 1996, and predates RFC 1951, on which the existing IPcomp is based and
> which we have supported in the kernel since 2003. So it seems rather
> unlikely that we will ever grow the need to support zlib-deflate.
>
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Support for zlib-deflate was added for [1] but that work was not
completed.

Based on [2], either we leave this SW implementation or we remove the HW
implementations in the QAT [3] and in the Hisilicon Zip [4] drivers.

[1] https://patchwork.kernel.org/project/linux-btrfs/patch/1467083180-111750-1-git-send-email-weigang.li@intel.com/
[2] https://lore.kernel.org/lkml/ZIw%2Fjtxdg6O1O0j3@gondor.apana.org.au/
[3] https://elixir.bootlin.com/linux/latest/source/drivers/crypto/intel/qat/qat_common/qat_comp_algs.c#L457
[4] https://elixir.bootlin.com/linux/latest/source/drivers/crypto/hisilicon/zip/zip_crypto.c#L754

Regards,

--
Giovanni