From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754822AbZBPUnT (ORCPT ); Mon, 16 Feb 2009 15:43:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751940AbZBPUnF (ORCPT ); Mon, 16 Feb 2009 15:43:05 -0500 Received: from ns2.mvista.com ([63.81.120.155]:1786 "EHLO imap.sh.mvista.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751881AbZBPUnD (ORCPT ); Mon, 16 Feb 2009 15:43:03 -0500 Message-ID: <4999CFEB.3030204@ru.mvista.com> Date: Mon, 16 Feb 2009 23:43:23 +0300 From: Sergei Shtylyov Organization: MontaVista Software Inc. User-Agent: Mozilla/5.0 (X11; U; Linux i686; rv:1.7.2) Gecko/20040803 X-Accept-Language: ru, en-us, en-gb MIME-Version: 1.0 To: Robert Hancock Cc: linux-kernel , ide , Jeff Garzik , Mark Lord , =?UTF-8?B?SGFubm8=?= =?UTF-8?B?IELDtmNr?= Subject: Re: [PATCH] libata: Don't trust current capacity values in identify words 57-58 References: <4999CA54.1060306@gmail.com> In-Reply-To: <4999CA54.1060306@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Robert Hancock wrote: > Hanno Böck reported a problem where an old Conner CP30254 240MB hard drive > was reported as 1.1TB in capacity by libata: > http://lkml.org/lkml/2009/2/13/134 > This was caused by libata trusting the drive's reported current capacity in > sectors in identify words 57 and 58 if the drive does not support LBA and the > current CHS translation values appear valid. Unfortunately it seems older > ATA specs were vague about what this field should contain and a number of drives > used values with wrong byte order or that were totally bogus. There's no > unique information that it conveys and so we can just calculate the number > of sectors from the reported current CHS values. > Signed-off-by: Robert Hancock > --- > Should likely go into -next for testing for a while. Of course, the fact that > this problem showed up in the first place shows that the number of people > that test libata with such boat anchors is fairly small :-) It's been tested well enough for years in the IDE core I think. > diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c > index 9fbf059..5389cbc 100644 > --- a/drivers/ata/libata-core.c > +++ b/drivers/ata/libata-core.c > @@ -1327,7 +1327,7 @@ static u64 ata_id_n_sectors(const u16 *id) > return ata_id_u32(id, 60); > } else { > if (ata_id_current_chs_valid(id)) > - return ata_id_u32(id, 57); > + return id[54] * id[55] * id[56]; We have mnemonics for these 3 words in ... MBR, Sergei