2024-02-29 10:14:01

by WangYuli

Subject: [PATCH v2] LoongArch/crypto: Clean up useless assignment operations

The LoongArch CRC32 hw acceleration is based on
arch/mips/crypto/crc32-mips.c. While the MIPS code supports both
MIPS32 and MIPS64, LA32 lacks the CRC instruction. As a result,
"line len -= sizeof(u32)" is unnecessary.

Removing it can make context code style more unified and improve
code readability.

Suggested-by: Guan Wentao <[email protected]>
Signed-off-by: WangYuli <[email protected]>
---
arch/loongarch/crypto/crc32-loongarch.c | 2 --
1 file changed, 2 deletions(-)

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);
}

if (len & sizeof(u16)) {
@@ -80,7 +79,6 @@ static u32 crc32c_loongarch_hw(u32 crc_, const u8 *p, unsigned int len)

CRC32C(crc, value, w);
p += sizeof(u32);
- len -= sizeof(u32);
}

if (len & sizeof(u16)) {
--
2.43.0

2024-03-08 10:25:02

by Herbert Xu

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 <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

2024-03-08 10:19:19

by Herbert Xu

Subject: Re: [PATCH v2] LoongArch/crypto: Clean up useless assignment operations

WangYuli <[email protected]> wrote:
> The LoongArch CRC32 hw acceleration is based on
> arch/mips/crypto/crc32-mips.c. While the MIPS code supports both
> MIPS32 and MIPS64, LA32 lacks the CRC instruction. As a result,
> "line len -= sizeof(u32)" is unnecessary.
>
> Removing it can make context code style more unified and improve
> code readability.
>
> Suggested-by: Guan Wentao <[email protected]>
> Signed-off-by: WangYuli <[email protected]>
> ---
> arch/loongarch/crypto/crc32-loongarch.c | 2 --
> 1 file changed, 2 deletions(-)
>
> 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.

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