From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Lendacky Subject: Re: [PATCH net] amd-xgbe: Fix jumbo MTU processing on newer hardware Date: Wed, 15 Mar 2017 17:52:44 -0500 Message-ID: <1b4a099a-66a8-3fdb-01ed-bc110756244a@amd.com> References: <20170315201123.12279.98988.stgit@tlendack-t1.amdoffice.net> <20170315.153710.150813448900229829.davem@davemloft.net> <20170315.154149.1161814285370679300.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Cc: To: David Miller Return-path: Received: from mail-by2nam01on0086.outbound.protection.outlook.com ([104.47.34.86]:22641 "EHLO NAM01-BY2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753983AbdCOWwx (ORCPT ); Wed, 15 Mar 2017 18:52:53 -0400 In-Reply-To: <20170315.154149.1161814285370679300.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On 3/15/2017 5:41 PM, David Miller wrote: > From: Tom Lendacky > Date: Wed, 15 Mar 2017 17:40:51 -0500 > >> On 3/15/2017 5:37 PM, David Miller wrote: >>> From: Tom Lendacky >>> Date: Wed, 15 Mar 2017 15:11:23 -0500 >>> >>>> Newer hardware does not provide a cumulative payload length when >>>> multiple >>>> descriptors are needed to handle the data. Once the MTU increases >>>> beyond >>>> the size that can be handled by a single descriptor, the SKB does not >>>> get >>>> built properly by the driver. >>>> >>>> The driver will now calculate the size of the data buffers used by the >>>> hardware. The first buffer of the first descriptor is for packet >>>> headers >>>> or packet headers and data when the headers can't be split. Subsequent >>>> descriptors in a multi-descriptor chain will not use the first >>>> buffer. The >>>> second buffer is used by all the descriptors in the chain for payload >>>> data. >>>> Based on whether the driver is processing the first, intermediate, or >>>> last >>>> descriptor it can calculate the buffer usage and build the SKB >>>> properly. >>>> >>>> Tested and verified on both old and new hardware. >>>> >>>> Signed-off-by: Tom Lendacky >>> >>> Applied, thanks Tom. >> >> Thanks David. This is another patch for 4.10 stable. Can you please >> queue it up? > > Can you properly state this in your patch postings, instead of always > mentioning it later? > Sorry, yes, I can do that. I didn't realize you preferred it that way. Do you want the "Cc" tag to stable included in the patch or just mention the stable targets in the patch description? I know you coordinate the stable submissions and I don't want to mess anything up. Thanks, Tom > Thank you. >