From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Martin K. Petersen" Subject: Re: [PATCH 2/2] sd: WRITE SAME(16) / UNMAP support Date: Fri, 30 Oct 2009 00:53:31 -0400 Message-ID: References: <1256873409-12668-1-git-send-email-martin.petersen@oracle.com> <1256873409-12668-3-git-send-email-martin.petersen@oracle.com> <4AEA6B76.2010303@interlog.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from acsinet11.oracle.com ([141.146.126.233]:29297 "EHLO acsinet11.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750794AbZJ3EzP (ORCPT ); Fri, 30 Oct 2009 00:55:15 -0400 In-Reply-To: <4AEA6B76.2010303@interlog.com> (Douglas Gilbert's message of "Fri, 30 Oct 2009 00:28:38 -0400") Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: dgilbert@interlog.com Cc: "Martin K. Petersen" , hch@infradead.org, axboe@kernel.dk, matthew@wil.cx, linux-scsi@vger.kernel.org >>>>> "Doug" == Douglas Gilbert writes: Doug> And if both are supported by the logical unit, the patch prefers Doug> UNMAP? Yes. SBC states that if the device reports MAXIMUM UNMAP LBA COUNT > 1 and MAXIMUM UNMAP DESCRIPTOR COUNT > 1 then the device supports UNMAP. And in that case that's what I'll issue. In all other cases I'll send out WRITE SAME(16). I believe that approach is what's currently considered best practice. -- Martin K. Petersen Oracle Linux Engineering