From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net] gso: Validate assumption of frag_list segementation Date: Fri, 21 Apr 2017 13:30:52 -0400 (EDT) Message-ID: <20170421.133052.1192709001555652314.davem@davemloft.net> References: <20170419182607.2342-1-ilant@mellanox.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, alexander.h.duyck@intel.com, eric.dumazet@gmail.com, steffen.klassert@secunet.com, borisp@mellanox.com, ilyal@mellanox.com To: ilant@mellanox.com Return-path: Received: from shards.monkeyblade.net ([184.105.139.130]:36046 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423281AbdDUSHh (ORCPT ); Fri, 21 Apr 2017 14:07:37 -0400 In-Reply-To: <20170419182607.2342-1-ilant@mellanox.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Date: Wed, 19 Apr 2017 21:26:07 +0300 > From: Ilan Tayari > > Commit 07b26c9454a2 ("gso: Support partial splitting at the frag_list > pointer") assumes that all SKBs in a frag_list (except maybe the last > one) contain the same amount of GSO payload. > > This assumption is not always correct, resulting in the following > warning message in the log: > skb_segment: too many frags > > For example, mlx5 driver in Striding RQ mode creates some RX SKBs with > one frag, and some with 2 frags. > After GRO, the frag_list SKBs end up having different amounts of payload. > If this frag_list SKB is then forwarded, the aforementioned assumption > is violated. > > Validate the assumption, and fall back to software GSO if it not true. > > Change-Id: Ia03983f4a47b6534dd987d7a2aad96d54d46d212 > Fixes: 07b26c9454a2 ("gso: Support partial splitting at the frag_list pointer") > Signed-off-by: Ilan Tayari > Signed-off-by: Ilya Lesokhin Applied.