Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751848AbZIUQlQ (ORCPT ); Mon, 21 Sep 2009 12:41:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751641AbZIUQlO (ORCPT ); Mon, 21 Sep 2009 12:41:14 -0400 Received: from TYO202.gate.nec.co.jp ([202.32.8.206]:43164 "EHLO tyo202.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751605AbZIUQlN (ORCPT ); Mon, 21 Sep 2009 12:41:13 -0400 Message-ID: <4AB7AAE2.8000404@ce.jp.nec.com> Date: Tue, 22 Sep 2009 01:33:38 +0900 From: "Jun'ichi Nomura" User-Agent: Thunderbird 2.0.0.23 (Windows/20090812) MIME-Version: 1.0 To: Jens Axboe , "Martin K. Petersen" CC: device-mapper development , Alasdair G Kergon , Mike Snitzer , linux-kernel@vger.kernel.org Subject: Re: [dm-devel] [PATCH 1/3] block: Add blk_queue_copy_limits() References: <4AB3B43D.9000802@ce.jp.nec.com> <4AB4F74E.7000908@ce.jp.nec.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1199 Lines: 29 Martin K. Petersen wrote: >>>>>> "Jun'ichi" == Jun'ichi Nomura writes: > > Jun'ichi> Umm, with this, BLK_DEF_MAX_SECTORS becomes upper bound of > Jun'ichi> max_hw_sectors and the values of underlying devices are not > Jun'ichi> propagated to the stacking devices. > > Well, max_sectors is already bounded by this. max_hw_sectors only > really matters for PC commands, so I'm not sure it's a big deal for > DM. But I guess we could set the default max_hw_sectors to -1. > > I'm just trying to avoid these scattered if-0-set-it-to-something-else > cases. I'd much rather have the defaults do the right thing. I agree with that. I had to do the if-0-set-it-to-something-else to avoid putting unnecessary cap on max_hw_sectors. If we aren't sure, shouldn't we set its default to -1 or putting comments in blk_set_default_limits() at least to avoid possible confusion in future? Thanks, -- Jun'ichi Nomura, NEC Corporation -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/