From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932157Ab0CIDNr (ORCPT ); Mon, 8 Mar 2010 22:13:47 -0500 Received: from acsinet11.oracle.com ([141.146.126.233]:20712 "EHLO acsinet11.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756626Ab0CIDNm (ORCPT ); Mon, 8 Mar 2010 22:13:42 -0500 To: Tejun Heo Cc: Karel Zak , "Martin K. Petersen" , "linux-ide\@vger.kernel.org" , lkml , Daniel Taylor , Jeff Garzik , Mark Lord , tytso@mit.edu, "H. Peter Anvin" , hirofumi@mail.parknet.co.jp, Andrew Morton , Alan Cox , irtiger@gmail.com, Matthew Wilcox , aschnell@suse.de, knikanth@suse.de, jdelvare@suse.de, Jim Meyering Subject: Re: ATA 4 KiB sector issues. From: "Martin K. Petersen" Organization: Oracle References: <4B947393.2050002@kernel.org> <20100308195847.GC18077@nb.net.home> <4B95B39C.70402@kernel.org> <4B95B5AC.8050101@gmail.com> Date: Mon, 08 Mar 2010 22:11:32 -0500 In-Reply-To: <4B95B5AC.8050101@gmail.com> (Tejun Heo's message of "Tue, 09 Mar 2010 11:42:52 +0900") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Source-IP: acsmt353.oracle.com [141.146.40.153] X-Auth-Type: Internal IP X-CT-RefId: str=0001.0A090208.4B95BCA0.002B:SCFMA4539814,ss=1,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>>>> "Tejun" == Tejun Heo writes: >> This will result in incorrect alignment for drives which lie about >> the physical sector size to work around BIOS/drivers issues (C-1). >> It would probably be best to align to at least 1MiB. Tejun> I misread it. C-1 would be disks w/o alignment information which Tejun> will be aligned to optimal_io_size which again would be 0 and Tejun> thus 1MiB alignment. So, this should work, right? Correct. ATA only provides physical block size whereas SCSI has the extra knobs in the block limits VPD. And consequently ATA block devices have min_io = physical block size and optimal_io = 0. So we'll align to 1 MB by default. -- Martin K. Petersen Oracle Linux Engineering