Date:   Thu, 26 Jan 2023 15:16:10 -0800
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Mikhail Zaslonko <zaslonko@linux.ibm.com>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Heiko Carstens <hca@linux.ibm.com>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Ilya Leoshkevich <iii@linux.ibm.com>
Subject: Re: [PATCH 0/8] lib/zlib: Set of s390 DFLTCC related patches for
 kernel zlib
Message-Id: <20230126151610.29e25c9870b77f0c880382bb@linux-foundation.org>
In-Reply-To: <20230126131428.1222214-1-zaslonko@linux.ibm.com>
References: <20230126131428.1222214-1-zaslonko@linux.ibm.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Precedence: bulk

On Thu, 26 Jan 2023 14:14:20 +0100 Mikhail Zaslonko <zaslonko@linux.ibm.com> wrote:

> Patches 1-7 represent a set of s390 zlib hardware support (DFLTCC) related fixes
> and enhancements integrated from zlib-ng repo relevant to kernel zlib
> (https://github.com/zlib-ng/zlib-ng).
> Since the official zlib repository never got DFLTCC support code merged, all
> the patches have been picked from zlib-ng fork (zlib data compression library
> for the next generation systems). This repo contains new optimizations and
> fixes not getting implemented into the official zlib repository and falls under
> the same zlib License. All of the original patches from zlib-ng were authored
> by Ilya Leoshkevich <iii@linux.ibm.com>. Coding style has been preserved for
> future maintainability.
> Patches 1-2 should have no effect for the kernel zlib but make the code
> closer to zlib-ng for future maintainability.
> Only Patch 3 touches common zlib_deflate code, other patches are relevant to
> s390 tree only.
> 
> Patch 8 is separate and intends to resolve an issue with kernel PPP driver
> which can use kernel zlib for packet compression. Without this patch PPP
> decompression can fail due to error code returned by hardware (dfltcc_inflate)
> and PPP disables zlib compression for further packets.
> 
> @Andrew, would you pick this patch series yourself (which is totally fine
> with me) or shall we carry it via s390 tree?

I'll grab.  zlib changes are pretty rare, but perhaps someone else will
do something..

> Mikhail Zaslonko (8):
>   lib/zlib: Adjust offset calculation for dfltcc_state
>   lib/zlib: Implement switching between DFLTCC and software
>   lib/zlib: Fix DFLTCC not flushing EOBS when creating raw streams
>   lib/zlib: Fix DFLTCC ignoring flush modes when avail_in == 0
>   lib/zlib: DFLTCC not writing header bits when avail_out == 0
>   lib/zlib: Split deflate and inflate states for DFLTCC
>   lib/zlib: DFLTCC support inflate with small window
>   lib/zlib: DFLTCC always switch to software inflate for Z_PACKET_FLUSH
>     option

Most of these have a github link in lieu of a changelog.  And most of
the github commits are unchangelogged.  That's pretty sad, but the zlib
audience is small and zlib isn't really kernel code anyway, so I guess
we can look the other way.