Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755007Ab0HCEpt (ORCPT ); Tue, 3 Aug 2010 00:45:49 -0400 Received: from rcsinet10.oracle.com ([148.87.113.121]:62178 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751453Ab0HCEps (ORCPT ); Tue, 3 Aug 2010 00:45:48 -0400 To: Christof Schmitt Cc: "Martin K. Petersen" , Jens Axboe , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [patch 0/1] Apply segment size and segment boundary to integrity data From: "Martin K. Petersen" Organization: Oracle References: <20100715153410.774329000@de.ibm.com> <20100716083034.GA7474@schmichrtp.ibm.com> <20100720092850.GA4547@schmichrtp.mainz.de.ibm.com> <20100802110517.GA4556@schmichrtp.mainz.de.ibm.com> Date: Tue, 03 Aug 2010 00:44:50 -0400 In-Reply-To: <20100802110517.GA4556@schmichrtp.mainz.de.ibm.com> (Christof Schmitt's message of "Mon, 2 Aug 2010 13:05:17 +0200") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Source-IP: acsmt354.oracle.com [141.146.40.154] X-Auth-Type: Internal IP X-CT-RefId: str=0001.0A090204.4C579EF5.0002:SCFMA4539814,ss=1,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1568 Lines: 35 >>>>> "Christof" == Christof Schmitt writes: Christof> To summarize the limits i see in the zfcp hardware: Christof> - Maximum size of 4k per segment Christof> - The segments must not cross page boundaries Christof> - The number of segments per request is limited The interesting thing here is that your hw has a limit for the total number of segments whereas other DIX HBAs have separate limits for data and integrity scatterlists. Christof> What would be the preferred approach for handling the Christof> integrity data limits in the block layer? Introduce new queue Christof> limits for integrity data, or assume that the limits for Christof> integrity data are the same as for user data? I can update my Christof> patch accordingly and include a check for the maximum number Christof> of segments. I've been messing with this tonight. It's not entirely trivial because of the housekeeping involved, having to accomodate different types of hardware, having to avoid breaking existing setups, and having to work with integrity compiled and without. My first attempt at this got quite messy. I think I have found a way but it's bedtime here. Give me a day or two to get back to you with something that'll hopefully work for everyone. -- Martin K. Petersen Oracle Linux Engineering -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/