Message-ID: <sashiko-outbox-201630@kernel.org>
From: sashiko-bot@kernel.org
Subject: Re: [PATCH v2 08/15] lib/lz4: add the build environment for the
 vendored sources
Reply-To: sashiko-reviews@lists.linux.dev
To: "Michal Wilczynski" <m.wilczynski@samsung.com>
Cc: linux-s390@vger.kernel.org, "Heiko Carstens" <hca@linux.ibm.com>, "Vasily
 Gorbik" <gor@linux.ibm.com>, "Alexander Gordeev" <agordeev@linux.ibm.com>, "Christian
 Borntraeger" <borntraeger@linux.ibm.com>
In-Reply-To: <20261106-lz4-vendor-upstream-v2-8-ee04c3f0d7dc@samsung.com>
References: <20261106-lz4-vendor-upstream-v2-0-ee04c3f0d7dc@samsung.com>
 <CGME20261106144301eucas1p1882c2f6ac262ef7c10c3e0cabe333a6b@eucas1p1.samsung.com>
 <20261106-lz4-vendor-upstream-v2-8-ee04c3f0d7dc@samsung.com>
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Date: Fri, 06 Nov 2026 14:57:35 +0000
Precedence: list

> lz4_deps.h makes the vendored upstream sources build in the kernel. It
> gives every upstream entry point internal linkage, so an object carries
> only the codec it forwards, selects heap mode with failing allocators so
> LZ4HC's ~64K optimal-parser buffer stays off the stack, and renames the
> entry points the kernel re-exports so the kernel's own definitions can
> use the real names. LZ4LIB_VISIBILITY carries __maybe_unused for the
> functions an object does not use.
>=20
> freestanding/ forwards the four ISO C headers upstream includes to their
> <linux/> equivalents. lz4_kernel_api.h undoes the renaming; it carries
> its own copy of the exported prototypes until a later patch can include
> <linux/lz4.h> instead.
>=20
> Two settings upstream leaves to the build:
>=20
>  - Unaligned access goes through memcpy() where the architecture has
>    efficient unaligned access, and through packed structs, as
>    get_unaligned() does, elsewhere. Left alone, upstream uses plain
>    misaligned loads on ARMv6.
>=20
>  - On ppc64le, lz4.c marks functions __attribute__((optimize("O2"))) for
>    GCC, which drops command line options such as -fno-strict-aliasing
>    for them; see commit 080b6f407635 ("bpf: Don't rely on GCC
>    __attribute__((optimize)) to disable GCSE"). lz4_deps.h defines
>    optimize() to nothing for upstream's sources.
>=20
> Nothing includes either header yet.
>=20
> Signed-off-by: Michal Wilczynski <m.wilczynski@samsung.com>

Sashiko has reviewed this patch and found no issues.

--=20
Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261106-lz4-vendor=
-upstream-v2-0-ee04c3f0d7dc@samsung.com?part=3D8