From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754780AbYKJQEb (ORCPT ); Mon, 10 Nov 2008 11:04:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753620AbYKJQEF (ORCPT ); Mon, 10 Nov 2008 11:04:05 -0500 Received: from smtp1.linux-foundation.org ([140.211.169.13]:43178 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753513AbYKJQEC (ORCPT ); Mon, 10 Nov 2008 11:04:02 -0500 Date: Mon, 10 Nov 2008 08:03:45 -0800 (PST) From: Linus Torvalds To: Tejun Heo cc: Jens Axboe , Jeff Garzik , IDE/ATA development list , Linux Kernel Subject: Re: request to revert libata-convert-to-block-tagging patches In-Reply-To: <491835FF.1060403@kernel.org> Message-ID: References: <4917C449.2080504@kernel.org> <20081110120533.GB26778@kernel.dk> <491835FF.1060403@kernel.org> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 10 Nov 2008, Tejun Heo wrote: > > I'm just a little bit nervous because libata always has had this tag 0 > for non-NCQ commands assumption and this conversion changes that, so I > was hoping to update blk-tag such that such assumption can be guaranteed > first and then convert libata to be on the safe side. Some controllers > use completely different command mechanism for different protocols and > it's much safer and more deterministic if same tag can be guaranteed. Yeah, I think that's a good argument. Even when controllers expect tags, it's certainyl quite possible that all they've ever been tested with have always started tag allocation from zero, so while the "start at an offset" thing is fairly clever for other reasons, it probably was the wrong thing to do. Maybe we can just have something count "outstanding async/sync requests". Linus