From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: [PATCH] Use a more selective error recovery strategy based on device capabilities Date: Wed, 13 Feb 2013 14:06:07 +0100 Message-ID: <511B8FBF.9000705@suse.de> References: <511A87CA.5010901@tributary.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from cantor2.suse.de ([195.135.220.15]:41860 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933965Ab3BMNGJ (ORCPT ); Wed, 13 Feb 2013 08:06:09 -0500 In-Reply-To: <511A87CA.5010901@tributary.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Jeremy Linton Cc: Linux Scsi , "Elliott, Robert (Server Storage)" On 02/12/2013 07:19 PM, Jeremy Linton wrote: > Ideally, Linux should not be sending task management commands to devi= ces that > don't support the given task mgmt operation. > > This patch uses the REPORT SUPPORTED TASK MGMT FUNCTIONS command to e= nable or > disable error recovery paths for a given device. For older devices, w= e make an > educated guess about what kind of error recovery the device supports.= This isn't > going to be 100% accurate as it should probably take the transport as= well as > the SCSI version into account, but it is a start. > > While this patch improves the error recovery paths for modern SCSI ne= tworks, the > error recovery logic continues to fall through to host reset. It also= continues > to send bus and target resets in cases where they may affect working = devices. I > have a partial set of patches which attempt to make intelligent decis= ions in > these cases, but they are far more intrusive and at this point not as= clear cut. > > > Just in case... > Signed-off-by: Jeremy Linton Nice concept. But unfortunately it failed the reality check; of my zoo of storage=20 arrays only NetApp OnTap 8.X and HP P2000 supports the REPORT SUPPORTED TASK MANAGEMENT FUNCTIONS command. None of the others (HP EVA, NetApp E-Series, EMC Clariion CX-3) do. So implementing this command won't buy us much, as it'll default to=20 the original behaviour for most cases ... (Not prejudicing any market share here, of course :-) Too bad. 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: J. Hawn, J. Guild, F. Imend=F6rffer, 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