From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1768830Ab2KOTk3 (ORCPT ); Thu, 15 Nov 2012 14:40:29 -0500 Received: from verein.lst.de ([213.95.11.211]:47264 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1768799Ab2KOTk1 (ORCPT ); Thu, 15 Nov 2012 14:40:27 -0500 X-Greylist: delayed 471 seconds by postgrey-1.27 at vger.kernel.org; Thu, 15 Nov 2012 14:40:27 EST Date: Thu, 15 Nov 2012 20:32:35 +0100 From: Christoph Hellwig To: "Nicholas A. Bellinger" Cc: Christoph Hellwig , target-devel , linux-scsi , linux-kernel , Christoph Hellwig , "Martin K. Petersen" Subject: Re: [PATCH 3/3] target/iblock: Add WRITE_SAME w/ UNMAP=0 emulation support Message-ID: <20121115193235.GA5714@lst.de> References: <1352405238-23267-1-git-send-email-nab@linux-iscsi.org> <1352405238-23267-4-git-send-email-nab@linux-iscsi.org> <20121115110432.GD28956@infradead.org> <1353007786.4447.29.camel@haakon2.linux-iscsi.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1353007786.4447.29.camel@haakon2.linux-iscsi.org> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 15, 2012 at 11:29:46AM -0800, Nicholas A. Bellinger wrote: > Well at least for the latter that is because UNMAP=0 does not have a > payload. ;) UNMAP=0 does have a payload, we just ignore it. In fact I was told that targets should check for a completely zeroed sector sized payload for it if being pedantic. I can't really find the justification for that in the standard - the closest thing to it is the stance about ignoring the unmap bit if the device is fully provisioned.