From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [PATCH] ipv6: udp packets following an UFO enqueued packet need also be handled by UFO Date: Wed, 02 Oct 2013 08:14:27 -0700 Message-ID: <1380726867.19002.104.camel@edumazet-glaptop.roam.corp.google.com> References: <20130930114343.GA6356@minipsycho.brq.redhat.com> <20130930172312.GE10771@order.stressinduktion.org> <20131001105837.GA1424@minipsycho.brq.redhat.com> <20131001120907.GH10771@order.stressinduktion.org> <20131001123214.GI10771@order.stressinduktion.org> <20131001214721.GJ10771@order.stressinduktion.org> <20131001232534.GM10771@order.stressinduktion.org> <20131002085842.GA1528@minipsycho.brq.redhat.com> <1380710488.19002.67.camel@edumazet-glaptop.roam.corp.google.com> <20131002121207.GO10771@order.stressinduktion.org> <20131002130329.GP10771@order.stressinduktion.org> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Jiri Pirko , netdev@vger.kernel.org, yoshfuji@linux-ipv6.org, davem@davemloft.net, kuznet@ms2.inr.ac.ru, jmorris@namei.org, kaber@trash.net, herbert@gondor.apana.org.au To: Hannes Frederic Sowa Return-path: Received: from mail-pb0-f44.google.com ([209.85.160.44]:42417 "EHLO mail-pb0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753653Ab3JBPOa (ORCPT ); Wed, 2 Oct 2013 11:14:30 -0400 Received: by mail-pb0-f44.google.com with SMTP id xa7so1016937pbc.17 for ; Wed, 02 Oct 2013 08:14:29 -0700 (PDT) In-Reply-To: <20131002130329.GP10771@order.stressinduktion.org> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, 2013-10-02 at 15:03 +0200, Hannes Frederic Sowa wrote: > On Wed, Oct 02, 2013 at 02:12:07PM +0200, Hannes Frederic Sowa wrote: > > Hi Eric! > > > > On Wed, Oct 02, 2013 at 03:41:28AM -0700, Eric Dumazet wrote: > > > On Wed, 2013-10-02 at 10:58 +0200, Jiri Pirko wrote: > > > > Wed, Oct 02, 2013 at 01:25:34AM CEST, hannes@stressinduktion.org wrote: > > > > >- if (((length > mtu) || (skb && skb_is_gso(skb))) && > > > > >+ if (((length > mtu) || (skb && skb_has_frags(skb))) && > > > > > > > > > > > This seems correct to me. sk_is_gso would work as well is you apply my > > > > patch "[patch net] ip6_output: do skb ufo init for peeked non ufo skb as > > > > well" which does the setting of gso_size. > > > > > > Well, skb having frags or not should not be a concern : > > > Thats an allocation choice (lets say to avoid high order allocations). > > > > > > Setting gso_size is probably better. > > > > e89e9cf539a28df7d0eb1d0a545368e9920b34ac ("[IPv4/IPv6]: UFO Scatter-gather > > approach") states: > > > > " > > skb->data will contain MAC/IP/UDP header and skb_shinfo(skb)->frags[] > > contains the data payload. The skb->ip_summed will be set to CHECKSUM_HW > > indicating that hardware has to do checksum calculation. Hardware should > > compute the UDP checksum of complete datagram and also ip header checksum of > > each fragmented IP packet. > > " > > > > This is the reason why I tried not to update the gso_size. If it is ok, I am > > fine with that. > > Especially, drivers/net/ethernet/neterion/s2io.c states that the first dma > mapping (skb->data with skb_headlen, which is fine) is used as the inband > header: > > if (offload_type == SKB_GSO_UDP) > frg_cnt++; /* as Txd0 was used for inband header */ > > That is my only other hint that we maybe should not update gso_size and > gso_type. I guess software fallback does not have this problem, but I won't > have time to check until this evening. > > I am really not sure if just setting gso_size does not break neterion UFO > offloading. :/ Well, just ask Jon Mason to double check ;) I think the commit intent was to set gso_size : skb_shinfo(skb)->ufo_size will indicate the length of data part in each IP fragment going out of the adapter after IP fragmentation by hardware. The fact that it states "skb->data will contain MAC/IP/UDP header and skb_shinfo(skb)->frags[] contains the data payload." seems irrelevant. If Neterion driver mandates that skb->head *only* contains the MAC/IP/UDP header, that should be handled in the driver itself.