From mboxrd@z Thu Jan  1 00:00:00 1970
From: Vincent Bernat <vincent@bernat.im>
Subject: Re: [PATCH net-next v1] ipvs: fix multiplicative hashing in sh/dh/lblc/lblcr algorithms
Date: Sun, 01 Apr 2018 12:16:10 +0200
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        <alpine.LFD.2.20.1804011037200.1933@ja.home.ssi.bg>
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In-Reply-To: <alpine.LFD.2.20.1804011037200.1933@ja.home.ssi.bg> (Julian
        Anastasov's message of "Sun, 1 Apr 2018 11:11:08 +0300 (EEST)")
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To: Julian Anastasov <ja@ssi.bg>
Cc: Wensong Zhang <wensong@linux-vs.org>, Simon Horman <horms@verge.net.au>, "David S. Miller" <davem@davemloft.net>, netdev@vger.kernel.org, lvs-devel@vger.kernel.org

 =E2=9D=A6  1 avril 2018 11:11 +0300, Julian Anastasov <ja@ssi.bg>=C2=A0:

>> -	return (ntohl(addr_fold)*2654435761UL) & IP_VS_DH_TAB_MASK;
>> +	return ((ntohl(addr_fold)*2654435761U) >>
>> +		(32 - IP_VS_DH_TAB_BITS)) &
>> +		IP_VS_DH_TAB_MASK;
>
> 	Looks like the '& mask' part is not needed, still,
> it does not generate extra code. I see that other code uses
> hash_32(val, bits) from include/linux/hash.h but note that it
> used different ratio before Linux 4.7, in case someone backports
> this patch on old kernels. So, I don't have preference what should
> be used, may be return hash_32(ntohl(addr_fold), IP_VS_DH_TAB_BITS)
> is better.

I didn't notice this macro. I think this is a better option. Let me
amend the patch.
--=20
Don't stop with your first draft.
            - The Elements of Programming Style (Kernighan & Plauger)