[PATCH] zlib: Fix big performance regression

[Tom Rini]

On Thu, Jun 27, 2024 at 10:25:21AM +0200, Christophe Leroy wrote:

> Commit 340fdf1303dc ("zlib: Port fix for CVE-2016-9841 to U-Boot")
> brings a big performance regression in inflate_fast(), which leads
> to watchdog timer reset on powerpc 8xx.
> 
> It looks like that commit does more than what it describe, it
> especially removed an important optimisation that was doing copies
> using halfwords instead of bytes. That unexpected change multiplied
> by almost 4 the time spent in inflate_fast() and increased by 40%
> the overall time needed to uncompress linux kernel image.
> 
> So partially revert that commit but keep post incrementation as it
> is the initial purpose of said commit.
> 
> Fixes: 340fdf1303dc ("zlib: Port fix for CVE-2016-9841 to U-Boot")
> Signed-off-by: Christophe Leroy <christophe.leroy at csgroup.eu>

Good work.

Reviewed-by: Tom Rini <trini at konsulko.com>

And can you please head over to https://github.com/madler/zlib and file
an issue, or pull request with your changes explaining why? I would hope
they're interested in performance regressions on slower parts still.
Thanks!

-- 
Tom
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