From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brian King Subject: Re: [PATCH] libsas: Don't issue commands to devices that have been hot-removed. Date: Thu, 06 Dec 2007 10:55:25 -0600 Message-ID: <4758297D.10909@linux.vnet.ibm.com> References: <200711301022.08001.kb@sysmikro.com.pl> <200712031709.54168.kb@sysmikro.com.pl> <20071203193652.GB7066@tree.beaverton.ibm.com> <200712032106.44176.kb@sysmikro.com.pl> <20071204223516.GA6767@tree.beaverton.ibm.com> <4755D941.2060903@garzik.org> <20071204231727.GB6767@tree.beaverton.ibm.com> Reply-To: brking@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from e32.co.us.ibm.com ([32.97.110.150]:57711 "EHLO e32.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751174AbXLFQzk (ORCPT ); Thu, 6 Dec 2007 11:55:40 -0500 Received: from d03relay02.boulder.ibm.com (d03relay02.boulder.ibm.com [9.17.195.227]) by e32.co.us.ibm.com (8.13.8/8.13.8) with ESMTP id lB6Frr9i014097 for ; Thu, 6 Dec 2007 10:53:53 -0500 Received: from d03av04.boulder.ibm.com (d03av04.boulder.ibm.com [9.17.195.170]) by d03relay02.boulder.ibm.com (8.13.8/8.13.8/NCO v8.7) with ESMTP id lB6GtR2R127348 for ; Thu, 6 Dec 2007 09:55:27 -0700 Received: from d03av04.boulder.ibm.com (loopback [127.0.0.1]) by d03av04.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id lB6GtQAa024866 for ; Thu, 6 Dec 2007 09:55:27 -0700 In-Reply-To: <20071204231727.GB6767@tree.beaverton.ibm.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: "Darrick J. Wong" Cc: Jeff Garzik , =?ISO-8859-1?Q?Krzysztof_B=3Faszkows?= =?ISO-8859-1?Q?ki?= , linux-scsi@vger.kernel.org, vst@vlnb.net, Alexis Bruemmer Darrick J. Wong wrote: > In general, I agree that sas-ata should adopt the new EH. > Unfortunately, I believe the old way of sas-ata configuring ATA ports is > somehow not compatible with the new EH stuff and causes a crash during > the device probe with my patch to move sas-ata to the new EH. If I > apply the patch that migrates sas-ata to use brking's latest ata-sas > configuration mechanism (the one that creates real ata_hosts), I see > (a) lots and lots of ATA hosts getting created (one per ATA port; > possibly undesirable if you've a SAS topology with a lot of SATA disks) The new libata EH ends up spending more time in the error handling thread than the old code did. One of the reasons having multiple ATA/SCSI hosts is a good thing is that is the granularity of error handling, so it prevents stalling all the other devices under that SAS HBA while we are hitting errors on an ATAPI SATA device, for example. Arguably, SATA users of libata already have one SCSI host per ATA port, so my SAS patches really just bring SAS in line with that design... -Brian -- Brian King Linux on Power Virtualization IBM Linux Technology Center