From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: [PATCH 4/4] sd: Handle ZBC drives correctly Date: Mon, 21 Jul 2014 13:51:26 +0200 Message-ID: <53CCFEBE.8080400@suse.de> References: <1405931241-92015-1-git-send-email-hare@suse.de> <1405931241-92015-5-git-send-email-hare@suse.de> <20140721112904.GB15455@infradead.org> 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]:48336 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753061AbaGULv2 (ORCPT ); Mon, 21 Jul 2014 07:51:28 -0400 In-Reply-To: <20140721112904.GB15455@infradead.org> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Christoph Hellwig Cc: linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org, James Bottomely On 07/21/2014 01:29 PM, Christoph Hellwig wrote: > On Mon, Jul 21, 2014 at 10:27:21AM +0200, Hannes Reinecke wrote: >> ZBC drives are close to disk devices, so update sd.c to handle >> ZBC drives correctly. > > While the other patches all look fine with me I strongly disagree wit= h > this one. Devices reporting the ZBC device type must have sequential > required zones, so they are _not_ anywhere close to disk devices, > and writes to them will cause errors that we aren't evenable able to > handle yet. > > If it makes some sort of experiment easier for you we can add a way t= o > force ZBC devices to use sd.c conditionally. Do you have a test devi= ce > that this works with? > Yes, I have. I was actually considering implementing a module option for sd (eg attach_zbc) to allow zac/zbc devices to be attached to the sd=20 driver. Which will be off per default, so your concern should be addressed. However, zbc devices _are_ similar to normal 'sd' devices; it's only=20 that some commands might fail unexpectedly. But all the usual commands from sbc are supported, so I found it a=20 bit odd having to implement my own device driver (which would be a=20 clone of 'sd' anyway). 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)