From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AB9EEC54FD0 for ; Mon, 27 Apr 2020 14:37:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8C78D20656 for ; Mon, 27 Apr 2020 14:37:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728025AbgD0OhR (ORCPT ); Mon, 27 Apr 2020 10:37:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35422 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1727115AbgD0OhR (ORCPT ); Mon, 27 Apr 2020 10:37:17 -0400 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 33A23C0610D5 for ; Mon, 27 Apr 2020 07:37:17 -0700 (PDT) Received: from localhost (unknown [IPv6:2a01:e0a:2c:6930:5cf4:84a1:2763:fe0d]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: bbrezillon) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id 43A212A074A; Mon, 27 Apr 2020 15:37:15 +0100 (BST) Date: Mon, 27 Apr 2020 16:37:11 +0200 From: Boris Brezillon To: Miquel Raynal Cc: Ricardo Ribalda Delgado , Richard Weinberger , Vignesh Raghavendra , linux-mtd@lists.infradead.org, LKML , Tudor Ambarus Subject: Re: [PATCH v2] mtd: Fix mtd not the same name not registered if nvmem Message-ID: <20200427163711.07614619@collabora.com> In-Reply-To: <20200427162222.1c2b2c85@xps13> References: <20200401100240.445447-1-ribalda@kernel.org> <20200402065953.9974-1-ribalda@kernel.org> <20200427162222.1c2b2c85@xps13> Organization: Collabora X-Mailer: Claws Mail 3.17.5 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 27 Apr 2020 16:22:22 +0200 Miquel Raynal wrote: > Hi Ricardo, > > Ricardo Ribalda Delgado wrote on Tue, 14 Apr 2020 > 15:47:23 +0200: > > > Ping? > > > > On Thu, Apr 2, 2020 at 8:59 AM Ricardo Ribalda Delgado > > wrote: > > > > > > When the nvmem framework is enabled, a nvmem device is created per mtd > > > device/partition. > > > > > > It is not uncommon that a device can have multiple mtd devices with > > > partitions that have the same name. Eg, when there DT overlay is allowed > > > and the same device with mtd is attached twice. > > > > > > Under that circumstances, the mtd fails to register due to a name > > > duplication on the nvmem framework. > > > > > > With this patch we add a _1, _2, _X to the subsequent names if there is > > > a collition, and throw a warning, instead of not starting the mtd > > > device. > > > > > > [ 8.948991] sysfs: cannot create duplicate filename '/bus/nvmem/devices/Production Data' > > > [ 8.948992] CPU: 7 PID: 246 Comm: systemd-udevd Not tainted 5.5.0-qtec-standard #13 > > > [ 8.948993] Hardware name: AMD Dibbler/Dibbler, BIOS 05.22.04.0019 10/26/2019 > > > [ 8.948994] Call Trace: > > > [ 8.948996] dump_stack+0x50/0x70 > > > [ 8.948998] sysfs_warn_dup.cold+0x17/0x2d > > > [ 8.949000] sysfs_do_create_link_sd.isra.0+0xc2/0xd0 > > > [ 8.949002] bus_add_device+0x74/0x140 > > > [ 8.949004] device_add+0x34b/0x850 > > > [ 8.949006] nvmem_register.part.0+0x1bf/0x640 > > > ... > > > [ 8.948926] mtd mtd8: Failed to register NVMEM device > > > > > > Signed-off-by: Ricardo Ribalda Delgado > > Thanks for proposing this change. Indeed we are aware of the problem > and the best solution that we could come up with was to create an > additional "unique_name" field to the mtd_info structure. This new > field would have the form: > > [] > > The separator might be '~' (but I am completely open on that), and that > would give for instance: > > my-controller~my-device~my-part~mysub-part I'd prefer something slightly more standard for the separator, like '/', which is what we usually use when we want to represent a path in a tree. I do agree on the general approach though. Note that controller name is normally hidden in the root MTD device name, and it's the driver responsibility to come up with a name that does not collide with other MTD drivers. We can of course try to pick a different name if we see another device with the same name, but we should definitely warn about that so drivers are patched accordingly.