From mboxrd@z Thu Jan 1 00:00:00 1970 From: Or Gerlitz Subject: Re: [net-next PATCH v2 5/9] mlx4: Add support for UDP tunnel segmentation with outer checksum offload Date: Tue, 3 May 2016 15:41:57 +0300 Message-ID: <57289C95.8030401@mellanox.com> References: <20160429222735.12418.61229.stgit@ahduyck-xeon-server> <20160429224333.12418.13862.stgit@ahduyck-xeon-server> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Cc: Or Gerlitz , Alexander Duyck , "talal@mellanox.com" , Linux Netdev List , Michael Chan , "David Miller" , Gal Pressman , "Eran Ben Elisha" To: Alexander Duyck Return-path: Received: from mail-db3on0088.outbound.protection.outlook.com ([157.55.234.88]:7534 "EHLO emea01-db3-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932687AbcECMmH (ORCPT ); Tue, 3 May 2016 08:42:07 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On 5/2/2016 6:41 PM, Alexander Duyck wrote: >> >Just one more piece to clarify... in the general case (e.g inner >> >packet size 1.5k...64k), the last segment would not have the same >> >length as the other segments, what happens on that case? > Actually in the case of GSO partial we have go through the software > segmentation code and trim off any last bit that doesn't match the MSS > of the rest of the frame. That way you end up with one frame that has > some number of MSS sized chunks, and then one remainder if there is a > frame that would be a different size. OK, thanks for further clarifying this, will look on the docs you pointed etc. From what you wrote here I understand it's indeed possible for one frame to be of different size from the rest, but the LCO thing still works somehow.. Or.