From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754089AbdC2HUG (ORCPT ); Wed, 29 Mar 2017 03:20:06 -0400 Received: from mail.free-electrons.com ([62.4.15.54]:56248 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753496AbdC2HUE (ORCPT ); Wed, 29 Mar 2017 03:20:04 -0400 Date: Wed, 29 Mar 2017 09:19:47 +0200 From: Boris Brezillon To: Masahiro Yamada Cc: linux-mtd@lists.infradead.org, Laurent Monat , thorsten.christiansson@idquantique.com, Enrico Jorns , Jason Roberts , Artem Bityutskiy , Dinh Nguyen , Marek Vasut , Brian Norris , Graham Moore , David Woodhouse , Masami Hiramatsu , Chuanxiao Dong , Jassi Brar , Linux Kernel Mailing List , Richard Weinberger , Cyrille Pitchen Subject: Re: [PATCH v2 20/53] mtd: nand: denali: do not set mtd->name Message-ID: <20170329091947.3619fd81@bbrezillon> In-Reply-To: References: <1490191680-14481-1-git-send-email-yamada.masahiro@socionext.com> <1490191680-14481-21-git-send-email-yamada.masahiro@socionext.com> <20170327173146.655f090f@bbrezillon> <20170328234023.0c887a51@bbrezillon> X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 29 Mar 2017 10:19:02 +0900 Masahiro Yamada wrote: > Hi Boris, > > 2017-03-29 6:40 GMT+09:00 Boris Brezillon : > > On Wed, 29 Mar 2017 06:32:24 +0900 > > Masahiro Yamada wrote: > > > >> Hi Boris, > >> > >> 2017-03-28 0:31 GMT+09:00 Boris Brezillon : > >> > On Wed, 22 Mar 2017 23:07:27 +0900 > >> > Masahiro Yamada wrote: > >> > > >> >> This will be filled by nand_scan_ident() later. > >> >> > >> >> Signed-off-by: Masahiro Yamada > >> >> --- > >> >> > >> >> Changes in v2: None > >> >> > >> >> drivers/mtd/nand/denali.c | 1 - > >> >> 1 file changed, 1 deletion(-) > >> >> > >> >> diff --git a/drivers/mtd/nand/denali.c b/drivers/mtd/nand/denali.c > >> >> index 3badb1d..1706975 100644 > >> >> --- a/drivers/mtd/nand/denali.c > >> >> +++ b/drivers/mtd/nand/denali.c > >> >> @@ -1495,7 +1495,6 @@ int denali_init(struct denali_nand_info *denali) > >> >> > >> >> /* now that our ISR is registered, we can enable interrupts */ > >> >> denali_set_intr_modes(denali, true); > >> >> - mtd->name = "denali-nand"; > >> > > >> > Are you sure this is safe to do that? When mtd->name is NULL, the core > >> > takes the parent name, and in the denali_dt case it's not "denali-nand", > >> > which means you're breaking mtdparts compat. > >> > >> How big impact is this? > > > > Breaking boot on some platforms (those defining partitions through > > mtdparts= cmdline parameter), which is not negligible :P. > > > >> > >> I think a bootloader could give mtdparts=denali-nand:... > >> but, now we are able to have partitions in DT nodes. > > > > Just because you have a new way to describe partitions (using DT) does > > not mean people are not using the old one (mtdparts= parameter). > > > I thought DT-node derived name can identify the hardware > even if multiple Denali controllers exist on an SoC. > > Anyway, I admit this is a kind of breakage. > > If this one is reject, I will drop it drop v3. > Yes, please keep the existing name, changing that without extra precautions has proven to be a bad idea [1]. Note that we now have a way to give user-friendly names to MTD devices through DT definitions [2]. So, if you ever want to assing a specific name to your NAND, all you have to do is add a label property to the NAND device node, and then, in the driver: nand_set_flash_node(chip, denali->dev->of_node); /* * Fallback to the default name if no label property was * defined. */ if (!mtd->name) mtd->name = "denali-nand"; [1]https://patchwork.ozlabs.org/patch/707065/ [2]https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/mtd/mtd.h?id=refs/tags/v4.11-rc4#n386