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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 F14F8C433ED for ; Wed, 7 Apr 2021 09:04:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ADD9661177 for ; Wed, 7 Apr 2021 09:04:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349895AbhDGJEs convert rfc822-to-8bit (ORCPT ); Wed, 7 Apr 2021 05:04:48 -0400 Received: from relay9-d.mail.gandi.net ([217.70.183.199]:47629 "EHLO relay9-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231787AbhDGJEr (ORCPT ); Wed, 7 Apr 2021 05:04:47 -0400 X-Originating-IP: 90.89.138.59 Received: from xps13 (lfbn-tou-1-1325-59.w90-89.abo.wanadoo.fr [90.89.138.59]) (Authenticated sender: miquel.raynal@bootlin.com) by relay9-d.mail.gandi.net (Postfix) with ESMTPSA id 51ECDFF80F; Wed, 7 Apr 2021 09:04:31 +0000 (UTC) Date: Wed, 7 Apr 2021 11:04:30 +0200 From: Miquel Raynal To: Yoshio Furuyama Cc: richard@nod.at, vigneshr@ti.com, linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/2] Fix the issue for clearing status process Message-ID: <20210407110430.327bc46f@xps13> In-Reply-To: References: Organization: Bootlin X-Mailer: Claws Mail 3.17.7 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Yoshio, Yoshio Furuyama wrote on Tue, 6 Apr 2021 10:47:26 +0900: Could you add "mtd: nand: bbt:" as prefix for the title (same for the other patch, even though you're not the original author). > In the unlikely event of bad block, > it should update its block status to BBT, > In this case, there are 2 kind of issue for handling > a) Mark bad block status to BBT: It was fixed by Patric's patch > b) Clear status to BBT: I posted patch for this issue > > Patch: > Issue of handing BBT (Bad Block Table) for > some particular blocks (Ex:10, 11) > Updating status is, first clear status, second set bad block status. > Patrick's patch is only fixed the issue for setting status process, > so this patch fix the clearing status process. This commit message is not clearly describing the situation, could you please reword it? > > Signed-off-by: Yoshio Furuyama > --- > drivers/mtd/nand/bbt.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/mtd/nand/bbt.c b/drivers/mtd/nand/bbt.c > index 64af6898131d..0780896eaafe 100644 > --- a/drivers/mtd/nand/bbt.c > +++ b/drivers/mtd/nand/bbt.c > @@ -112,11 +112,13 @@ int nanddev_bbt_set_block_status(struct nand_device *nand, unsigned int entry, > ((entry * bits_per_block) / BITS_PER_LONG); > unsigned int offs = (entry * bits_per_block) % BITS_PER_LONG; > unsigned long val = status & GENMASK(bits_per_block - 1, 0); > + unsigned long shift = ((bits_per_block + offs <= BITS_PER_LONG) ? > + (offs + bits_per_block - 1) : (BITS_PER_LONG - 1)); Given the fact that we do arithmetic operations (&, |) on an unsigned long value I don't think the operation tampers with the next entry in the pos array. I'm fine fixing it but I don't think this implementation works. It is fine if offs is 29 or 30 but not if it is 31 (assuming 32-bits arithmetic, it's the same for the 64-bit case). > > if (entry >= nanddev_neraseblocks(nand)) > return -ERANGE; > > - pos[0] &= ~GENMASK(offs + bits_per_block - 1, offs); Would something like the following work? pos[0] &= ~GENMASK(MIN(offs + bits_per_block - 1, BITS_PER_LONG - 1), offs) Again, I am not convinced it is worth darkening the logic unless I am not understanding it correctly. > + pos[0] &= ~GENMASK(shift, offs); > pos[0] |= val << offs; > > if (bits_per_block + offs > BITS_PER_LONG) { Thanks, Miquèl