From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752257Ab0IMJVe (ORCPT ); Mon, 13 Sep 2010 05:21:34 -0400 Received: from cantor2.suse.de ([195.135.220.15]:33437 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750843Ab0IMJVd (ORCPT ); Mon, 13 Sep 2010 05:21:33 -0400 Message-ID: <4C8DED17.6080801@suse.de> Date: Mon, 13 Sep 2010 11:21:27 +0200 From: Hannes Reinecke User-Agent: Thunderbird 2.0.0.19 (X11/20081227) MIME-Version: 1.0 To: "Nicholas A. Bellinger" Cc: linux-scsi , linux-kernel , Christoph Hellwig , FUJITA Tomonori , Mike Christie , James Bottomley , Konrad Rzeszutek Wilk , Boaz Harrosh , Richard Sharpe , Mike Christie , Vasu Dev , Joe Eykholt Subject: Re: [PATCH 0/2] lio-target: Add support for libcrypto crc32c and crc32-intel offload References: <1284201076-22361-1-git-send-email-nab@linux-iscsi.org> In-Reply-To: <1284201076-22361-1-git-send-email-nab@linux-iscsi.org> X-Enigmail-Version: 0.95.7 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Nicholas A. Bellinger wrote: > From: Nicholas Bellinger > > Greetings all, > > This patch series converts the LIO-Target fabric module from using a legacy > internal slicing by 1x CRC32C algorithm to the slicing by 1x CRC32C available in > crc32c.ko, as well as initial support for the Nehalem series crc32c-intel.ko > instruction offload available since v2.6.27 in late 2008. > > So far this series has been lightly tested with a handful of Open-iSCSI client VMs > with the optimized crc32c-intel.ko offload case, and there appears to be some > HeaderDigest failures for one case with RHEL6 B2 x86_64, while Ubuntu i686 on > v2.6.27 and OpenSuse 11.2 x86_64 on v2.6.31 work as expected with HeaderDigest=CRC32C > and DataDigest=CRC32C using the offload on the LIO-Target side. > > Currently this patch disables the new iSCSI TPG attribute crc32c_x86_offload > to force the crc32c.ko slicing by x1 CRC32C algorithm until these compatibility > issues with existing libcrc32c clients can be properly resolved with the Nehalem > CRC32C offload instructions running on the LIO-Target side. > Due to a customer issue I had to revisit the CRC32 issue recently. And according to you the main reason for using your own CRC routines had been endianness issues. IE the in-kernel crc32c routines apparently weren't able to calculate the checksum in an endianness-independent manner. So a CRC calculated on a BE machine would fail to be validated by a LE machine and vice versa. Has this been fixed / verified? Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: Markus Rex, HRB 16746 (AG Nürnberg)