From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: wireless vs. alignment requirements
Date: Sat, 24 Nov 2007 05:51:15 -0800 (PST)
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From: Johannes Berg <johannes@sipsolutions.net>
Date: Sat, 24 Nov 2007 14:49:36 +0100

> 
> On Sat, 2007-11-24 at 21:32 +0800, Herbert Xu wrote:
> > On Sat, Nov 24, 2007 at 09:33:36AM +0100, Johannes Berg wrote:
> > >
> > > We still require four-byte alignment, no?
> > 
> > Not at all.  If NET_IP_ALIGN is zero then it won't be four-byte
> > aligned (since the Ethernet header is 14 bytes long).
> 
> Right. I just didn't think that would be a valid value for an
> architecture to set.

It is, and explicitly used by powerpc to get more of the
DMA transfers 64-byte aligned which is critical for
performance on some powerpc boxes.