Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754867Ab2JBWvA (ORCPT ); Tue, 2 Oct 2012 18:51:00 -0400 Received: from server505f.appriver.com ([98.129.35.10]:3837 "EHLO server505.appriver.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753198Ab2JBWu6 convert rfc822-to-8bit (ORCPT ); Tue, 2 Oct 2012 18:50:58 -0400 X-Note-AR-ScanTimeLocal: 10/2/2012 5:50:57 PM X-Policy: GLOBAL - coraid.com X-Policy: GLOBAL - coraid.com X-Primary: ecashin@coraid.com X-Note: This Email was scanned by AppRiver SecureTide X-ALLOW: @coraid.com ALLOWED X-Virus-Scan: V- X-Note: Spam Tests Failed: X-Country-Path: UNKNOWN->UNITED STATES->UNITED STATES X-Note-Sending-IP: 98.129.35.1 X-Note-Reverse-DNS: smtp.exg5.exghost.com X-Note-Return-Path: ecashin@coraid.com X-Note: User Rule Hits: X-Note: Global Rule Hits: G321 G322 G323 G324 G328 G329 G340 G436 X-Note: Encrypt Rule Hits: X-Note: Mail Class: ALLOWEDSENDER X-Note: Headers Injected From: Ed Cashin To: Andrew Morton CC: "linux-kernel@vger.kernel.org" Date: Tue, 2 Oct 2012 17:50:55 -0500 Subject: Re: [PATCH 4/7] aoe: make dynamic block minor numbers the default Thread-Topic: [PATCH 4/7] aoe: make dynamic block minor numbers the default Thread-Index: Ac2g8GH9xtcT0lWJSI2HaA2REId6Fg== Message-ID: <4FD96533-B1C0-4795-993C-AE188AD894D9@coraid.com> References: <3c9c2338b9c963e1d5f19cc9ed51b01cf829eeee.1349104674.git.ecashin@coraid.com> <4b1456739285d5a7a153ba74a51f3e3bfd5c4a53.1349104674.git.ecashin@coraid.com> <20121002141734.56ee52b3.akpm@linux-foundation.org> In-Reply-To: <20121002141734.56ee52b3.akpm@linux-foundation.org> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1533 Lines: 41 On Oct 2, 2012, at 5:17 PM, Andrew Morton wrote: ... >> The static arrangement is still available with aoe_dyndevs=0, and >> the aoe-stat tool from the userland aoetools package, the user >> space counterpart to the aoe driver, recognizes the case where >> there is a mismatch between the minor number in sysfs and the >> minor number in a special device file. > > Oh. There we are. > > Again, what are the back-(in)compatibility issues which users might > encounter with this? I think the people who care about aoe_dyndevs=0 are the people creating an initramfs without udev and with AoE targets that have low shelf and slot numbers for addresses. They might want a tiny bzImage that can boot off AoE storage using device nodes prepared in advance with mknod. The old static mapping is a nice fit for that use case. There could be others with a reason not to use udev, but none of those others have ever communicated with me, if they exist. It's probably confusing the way I did the commits, making static the default before explicitly changing it to dynamic, but usually the people who actually care about this are so technical that I expect them to read the git logs, and I wanted to leave a paper trail there for anyone reading later. -- Ed Cashin ecashin@coraid.com -- 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/