From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [net-next PATCH 3/5] udp: Add support for software checksum and GSO_PARTIAL with GSO offload Date: Thu, 3 May 2018 20:50:52 -0700 Message-ID: References: <20180504002817.4496.64616.stgit@localhost.localdomain> <20180504003333.4496.7705.stgit@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit To: Alexander Duyck , netdev@vger.kernel.org, willemb@google.com, davem@davemloft.net, Steffen Klassert Return-path: Received: from mail-pg0-f65.google.com ([74.125.83.65]:42153 "EHLO mail-pg0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751326AbeEDDuy (ORCPT ); Thu, 3 May 2018 23:50:54 -0400 Received: by mail-pg0-f65.google.com with SMTP id p9-v6so11657591pgc.9 for ; Thu, 03 May 2018 20:50:54 -0700 (PDT) In-Reply-To: <20180504003333.4496.7705.stgit@localhost.localdomain> Content-Language: en-US Sender: netdev-owner@vger.kernel.org List-ID: On 05/03/2018 05:33 PM, Alexander Duyck wrote: > From: Alexander Duyck > > This patch adds support for a software provided checksum and GSO_PARTIAL > segmentation support. With this we can offload UDP segmentation on devices > that only have partial support for tunnels. > > Since we are no longer needing the hardware checksum we can drop the checks > in the segmentation code that were verifying if it was present. > > Signed-off-by: Alexander Duyck > --- > net/ipv4/udp_offload.c | 28 ++++++++++++++++++---------- > net/ipv6/udp_offload.c | 11 +---------- > 2 files changed, 19 insertions(+), 20 deletions(-) > > diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c > index 946d06d2aa0c..fd94bbb369b2 100644 > --- a/net/ipv4/udp_offload.c > +++ b/net/ipv4/udp_offload.c > @@ -217,6 +217,13 @@ struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb, > return segs; > } > > + /* GSO partial and frag_list segmentation only requires splitting > + * the frame into an MSS multiple and possibly a remainder, both > + * cases return a GSO skb. So update the mss now. > + */ > + if (skb_is_gso(segs)) > + mss *= skb_shinfo(segs)->gso_segs; > + > I do not understand this code. I am also seeing it in tcp, after commit 07b26c9454a2a ("gso: Support partial splitting at the frag_list pointer") Presumably this broke tcp_gso_tstamp() , right ?