netdev - Re: [PATCH net] bonding: discard lowest hash bit for 802.3ad layer3+4

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Message-ID: <20171106005921.GA13972@leo.usersys.redhat.com>
Date:   Mon, 6 Nov 2017 08:59:21 +0800
From:   Hangbin Liu <liuhangbin@...il.com>
To:     Eric Dumazet <edumazet@...gle.com>
Cc:     netdev <netdev@...r.kernel.org>, Paolo Abeni <pabeni@...hat.com>,
        "David S. Miller" <davem@...emloft.net>
Subject: Re: [PATCH net] bonding: discard lowest hash bit for 802.3ad layer3+4

On Sun, Nov 05, 2017 at 01:38:47PM -0800, Eric Dumazet wrote:
> > diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
> > index c99dc59..728fa08 100644
> > --- a/drivers/net/bonding/bond_main.c
> > +++ b/drivers/net/bonding/bond_main.c
> > @@ -3237,7 +3237,7 @@ u32 bond_xmit_hash(struct bonding *bond, struct sk_buff *skb)
> >
> >         if (bond->params.xmit_policy == BOND_XMIT_POLICY_ENCAP34 &&
> >             skb->l4_hash)
> > -               return skb->hash;
> > +               return skb->hash >> 1;
> 
> Why are you changing this part ?
> 
> The l4 hash provided by local TCP stack does not use a pathological
> XOR based on ports/addresses,
> but a random value with pretty good entropy.
> 

Oh, my bad. I only tested the patch works, but not carefully check the
skb->hash when skb->l4_hash is 1. Will send a v2 patch to fix this.

Regards
Hangbin