From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: [PATCH 0/2] lio-target: Add support for libcrypto crc32c and crc32-intel offload Date: Mon, 13 Sep 2010 11:21:27 +0200 Message-ID: <4C8DED17.6080801@suse.de> References: <1284201076-22361-1-git-send-email-nab@linux-iscsi.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: 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 In-Reply-To: <1284201076-22361-1-git-send-email-nab@linux-iscsi.org> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org 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 Nicholas A. Bellinger wrote: > From: Nicholas Bellinger >=20 > Greetings all, >=20 > 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 a= vailable in > crc32c.ko, as well as initial support for the Nehalem series crc32c-i= ntel.ko > instruction offload available since v2.6.27 in late 2008. >=20 > So far this series has been lightly tested with a handful of Open-iSC= SI 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 Hea= derDigest=3DCRC32C > and DataDigest=3DCRC32C using the offload on the LIO-Target side. >=20 > Currently this patch disables the new iSCSI TPG attribute crc32c_x86_= offload > to force the crc32c.ko slicing by x1 CRC32C algorithm until these com= patibility > issues with existing libcrc32c clients can be properly resolved with = the Nehalem > CRC32C offload instructions running on the LIO-Target side. >=20 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 --=20 Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=FCrnberg GF: Markus Rex, HRB 16746 (AG N=FCrnberg) -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html