Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752673Ab2HTSay (ORCPT ); Mon, 20 Aug 2012 14:30:54 -0400 Received: from avon.wwwdotorg.org ([70.85.31.133]:41041 "EHLO avon.wwwdotorg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751116Ab2HTSav (ORCPT ); Mon, 20 Aug 2012 14:30:51 -0400 Message-ID: <50328258.9030800@wwwdotorg.org> Date: Mon, 20 Aug 2012 12:30:48 -0600 From: Stephen Warren User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120714 Thunderbird/14.0 MIME-Version: 1.0 To: Tejun Heo CC: "linux-kernel@vger.kernel.org" , Will Drewry , "cross-distro@lists.linaro.org" , Jens Axboe , Kay Sievers Subject: Re: root=PARTUUID for MBR/NT disk signatures? References: <502EC16C.4030007@wwwdotorg.org> <20120820182254.GQ24861@google.com> In-Reply-To: <20120820182254.GQ24861@google.com> X-Enigmail-Version: 1.5a1pre 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: 1658 Lines: 39 On 08/20/2012 12:22 PM, Tejun Heo wrote: > Hello, > > On Fri, Aug 17, 2012 at 04:10:52PM -0600, Stephen Warren wrote: >> I was considering extending the kernel command-line option >> root=PARTUUID= to also support MBR (NT disk signatures). I was thinking >> of a syntax along the lines of: >> >> root=PARTUUID=UUUUUUUU-PP[/PARTNROFF=%d] >> >> ... where UUUUUUUU is the hex representation of the NT disk signature, >> and PP is the hex representation of the partition number. Like GPT, >> /PARTNROFF could be used too if desired. >> >> Related, I was thinking of changing struct partition_meta_info's uuid >> field to be a string, so that it could simply be strcmp'd against the >> UUID value on the kernel command-line. That way, the type of the UUID is >> irrelevant. >> >> Does anyone have any objection to that? > > Wouldn't that be able to break setups which work currently? I don't believe so: Since the newly supported UUID syntax wouldn't ever match any EFI UUID (the lengths differ in all cases), I don't believe the new syntax would affect behavior for any existing usage. Obviously, part_efi.c would be modified to initialize struct partition_meta_info's uuid field to the appropriate string representation of the UUID so that the str(case)cmp would still succeed for existing command-lines. I ended up coding up that part of the change late Friday, and the feature was certainly still working OK. -- 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/