[Devel] Re: [BRIDGE] Unaligned access on IA64 when comparing ethernet addresses

[Stephen Hemminger]

On Wed, 18 Apr 2007 01:28:04 -0700 (PDT)
David Miller <davem at davemloft.net> wrote:

> From: Pavel Emelianov <xemul at sw.ru>
> Date: Wed, 18 Apr 2007 10:43:56 +0400
> 
> > [snip]
> > 
> > > --- linux-2.6.orig/net/bridge/br_private.h	2007-04-17
> > > 13:26:48.000000000 -0700 +++ linux-2.6/net/bridge/br_private.h
> > > 2007-04-17 13:30:29.000000000 -0700 @@ -36,7 +36,7 @@
> > >  {
> > >  	unsigned char	prio[2];
> > >  	unsigned char	addr[6];
> > > -};
> > > +} __attribute__((aligned(8)));
> > 
> > Why "8"? Mustn't it be "16"? Address is to be 2-bytes aligned...
> 
> Actually it could be made "2", the aligned() attribute is
> in bytes, not bits.

It could be 2 but 8 might allow a compiler on a 64 bit platform
to be smarter in comparisons and assignments. For 2.6.22, I'll make
a nicer version similar to ktime_t.