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Date: Tue, 10 Nov 2026 14:31:51 +0900
From: Sergey Senozhatsky <senozhatsky@chromium.org>
To: sashiko-reviews@lists.linux.dev
Cc: Michal Wilczynski <m.wilczynski@samsung.com>, 
	Nathan Chancellor <nathan@kernel.org>, Nick Desaulniers <ndesaulniers@google.com>, 
	Bill Wendling <morbo@google.com>, Justin Stitt <justinstitt@google.com>, 
	Russell King <linux@armlinux.org.uk>, Thomas Bogendoerfer <tsbogend@alpha.franken.de>, 
	"James E.J. Bottomley" <James.Bottomley@hansenpartnership.com>, Helge Deller <deller@gmx.de>, Heiko Carstens <hca@linux.ibm.com>, 
	Vasily Gorbik <gor@linux.ibm.com>, Alexander Gordeev <agordeev@linux.ibm.com>, 
	Christian Borntraeger <borntraeger@linux.ibm.com>, Sven Schnelle <svens@linux.ibm.com>, 
	Thomas Gleixner <tglx@kernel.org>, Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>, 
	Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>, 
	Minchan Kim <minchan@kernel.org>, Sergey Senozhatsky <senozhatsky@chromium.org>, 
	Jens Axboe <axboe@kernel.dk>, Andrew Morton <akpm@linux-foundation.org>, 
	linux-s390@vger.kernel.org, Yann Collet <yann.collet.73@gmail.com>, 
	Nick Terrell <terrelln@meta.com>, Gao Xiang <xiang@kernel.org>, Chao Yu <chao@kernel.org>, 
	Jaegeuk Kim <jaegeuk@kernel.org>, Eric Biggers <ebiggers@kernel.org>, 
	Herbert Xu <herbert@gondor.apana.org.au>, David Laight <david.laight.linux@gmail.com>, 
	Sungguk <sungguk.na@samsung.com>, Jaehoon Chung <jh80.chung@samsung.com>, 
	Marek Szyprowski <m.szyprowski@samsung.com>, linux-crypto@vger.kernel.org
Subject: Re: [PATCH v2 03/15] zram: lz4hc: reset the dictionary stream once,
 not per page
Message-ID: <avKrj0h8fBNSrfCi@google.com>
References: <20261106-lz4-vendor-upstream-v2-0-ee04c3f0d7dc@samsung.com>
 <CGME20261106144252eucas1p272c9e37d66ad385db070f941879aecb1@eucas1p2.samsung.com>
 <20261106-lz4-vendor-upstream-v2-3-ee04c3f0d7dc@samsung.com>
 <sashiko-outbox-201613@kernel.org>
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In-Reply-To: <sashiko-outbox-201613@kernel.org>

On (26/11/06 14:49), sashiko-bot@kernel.org wrote:
> Thank you for your contribution! Sashiko AI review found no new issues
> in this patch, but noticed 1 related pre-existing issue it does not
> introduce:
> - [Medium] zram: high-order memory allocation using kzalloc in
>   lz4hc_create() [1]
> --
> 
> commit 2f51683dc7418bdcd0730283cb7003d8754fcd5f
> Author: Michal Wilczynski <m.wilczynski@samsung.com>
> 
> zram: lz4hc: reset the dictionary stream once, not per page
> 
> This commit moves the LZ4_resetStreamHC() call for dictionary-backed
> streams from lz4hc_compress() to lz4hc_create() so that the stream state is
> only reset once at creation time rather than on every compressed page.
> 
> > diff --git a/drivers/block/zram/backend_lz4hc.c b/drivers/block/zram/backend_lz4hc.c
> > index d8aa01bb258fe..06286c805cf7c 100644
> > --- a/drivers/block/zram/backend_lz4hc.c
> > +++ b/drivers/block/zram/backend_lz4hc.c
> > @@ -72,6 +72,7 @@ static int lz4hc_create(struct zcomp_params *params, struct zcomp_ctx *ctx)
> >  		zctx->cstrm = kzalloc_obj(*zctx->cstrm);
> >  		if (!zctx->cstrm)
> >  			goto error;
> > +		LZ4_resetStreamHC(zctx->cstrm, params->level);
> >  	}
> 
> [Severity: Medium]
> This problem wasn't introduced by this patch, but should zctx->cstrm be
> allocated with vmalloc() or kvzalloc() instead of kzalloc_obj() [1]?

That's how I have it in my local tree - vmalloc(LZ4HC_MEM_COMPRESS).
Michal, I suppose you don't base the series on top of linux-next or
Andrew's tree?

We reset the stream when we setup params, so I don't think we need
to do anything in lz4hc_create().