Subject: Re: [PATCH] flow-dissector: Fix alignment issue in __skb_flow_get_ports

From: Alexander Duyck <[email-masked]>
Date: Fri, 10 Oct 2014 11:02:04 -0700

On 10/10/2014 10:58 AM, David Miller wrote:
> From: Alexander Duyck <[email-masked]>
> 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.

I'll do some digging.  I know I had this working in igb/ixgbe before so
I probably just need to add a few small tweaks to resolve the remaining
issues for v4 of the patch.

Thanks,

Alex