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From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH] flow-dissector: Fix alignment issue in
 __skb_flow_get_ports
Date: Fri, 10 Oct 2014 13:58:51 -0400 (EDT)
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From: Alexander Duyck <alexander.h.duyck@redhat.com>
Date: Fri, 10 Oct 2014 09:50:17 -0700

> If I just use get_unaligned that is pretty easy in terms of cleanup
> for the ports and IPv4 addresses, the IPv6 will still be a significant
> hurdle to overcome though.

Actually, it's not that simple.

When the compiler sees things like "th->doff" it will load the 32-bit
word that 4-bit field contains and extract the value using shifts and
masking.

So we might need to sprinkle a "attribute((packed))" here and there
to make it work.