linux-kernel - Re: [PATCH v2] LoongArch/crypto: Clean up useless assignment operations

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Date: Fri, 8 Mar 2024 18:25:01 +0800
From: Herbert Xu <herbert@...dor.apana.org.au>
To: WangYuli <wangyuli@...ontech.com>
Cc: davem@...emloft.net, chenhuacai@...nel.org, kernel@...0n.name,
	linux-crypto@...r.kernel.org, loongarch@...ts.linux.dev,
	linux-kernel@...r.kernel.org, guanwentao@...ontech.com
Subject: Re: [PATCH v2] LoongArch/crypto: Clean up useless assignment
 operations

On Fri, Mar 08, 2024 at 06:19:02PM +0800, Herbert Xu wrote:
>
> > diff --git a/arch/loongarch/crypto/crc32-loongarch.c b/arch/loongarch/crypto/crc32-loongarch.c
> > index a49e507af38c..3eebea3a7b47 100644
> > --- a/arch/loongarch/crypto/crc32-loongarch.c
> > +++ b/arch/loongarch/crypto/crc32-loongarch.c
> > @@ -44,7 +44,6 @@ static u32 crc32_loongarch_hw(u32 crc_, const u8 *p, unsigned int len)
> > 
> >                CRC32(crc, value, w);
> >                p += sizeof(u32);
> > -               len -= sizeof(u32);
> >        }
> 
> This makes no sense whatsoever.  Please review this patch carefully
> before you resubmit.

Nevermind, I see what's going on now.  Your reference to the lack
of a CRC instruction utterly confused me.

The fact that len -= is unnecessary has nothing to do with whether
there is a CRC instruction.

Please modify your patch description so that it is not needlessly
confusing.  You should simply state that len -= is unnecessary
because you only test whether the relevant bit is set in len for
the tail case.

Thanks,
-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt