On 22/08/16 16:42, Vitaly Kuznetsov wrote: > > I see two ways to fix the issue: > - Change the 'wire' protocol between netfront and netback to start keeping > the original SKB structure. We'll have to add a flag indicating the fact > that the particular request is a part of the original linear part and not > a frag. We'll need to know the length of the linear part to pre-allocate > memory.
I don't think there needs to be a protocol change. I think the check in netback is bogus -- it's the total packet length that must be > HLEN_ETH. The upper layers will pull any headers from the frags as needed (or if necessary, netback could pull a minimum amount). There's no need to preserve the skb layout (e.g., look how the to-guest direction we do not do this). David
