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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0E8D5C433EF for ; Wed, 20 Oct 2021 08:53:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DD4D0611EF for ; Wed, 20 Oct 2021 08:53:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230123AbhJTIzp (ORCPT ); Wed, 20 Oct 2021 04:55:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58658 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230070AbhJTIzo (ORCPT ); Wed, 20 Oct 2021 04:55:44 -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 E2295C06161C for ; Wed, 20 Oct 2021 01:53:30 -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 32EFD1F43F4A; Wed, 20 Oct 2021 09:53:29 +0100 (BST) Date: Wed, 20 Oct 2021 10:53:26 +0200 From: Boris Brezillon To: Sean Nyekjaer Cc: Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , Boris Brezillon , linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 1/4] mtd: rawnand: nand_bbt: hide suspend/resume hooks while scanning bbt Message-ID: <20211020105326.0dca864a@collabora.com> In-Reply-To: <20211020084534.2472305-2-sean@geanix.com> References: <20211020084534.2472305-1-sean@geanix.com> <20211020084534.2472305-2-sean@geanix.com> Organization: Collabora X-Mailer: Claws Mail 3.18.0 (GTK+ 2.24.33; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 20 Oct 2021 10:45:31 +0200 Sean Nyekjaer wrote: > From: Boris Brezillon > > The BBT scan logic use the MTD helpers before the MTD layer had a > chance to initialize the device, and that leads to issues when > accessing the uninitialized suspend lock. Let's temporarily set the > suspend/resume hooks to NULL to skip the lock acquire/release step. > > Fixes: 013e6292aaf5 ("mtd: rawnand: Simplify the locking") > Tested-by: Sean Nyekjaer It's missing our Signed-off-by tags. > --- > drivers/mtd/nand/raw/nand_bbt.c | 28 +++++++++++++++++++++++++++- > 1 file changed, 27 insertions(+), 1 deletion(-) > > diff --git a/drivers/mtd/nand/raw/nand_bbt.c b/drivers/mtd/nand/raw/nand_bbt.c > index b7ad030225f8..93d385703469 100644 > --- a/drivers/mtd/nand/raw/nand_bbt.c > +++ b/drivers/mtd/nand/raw/nand_bbt.c > @@ -1397,8 +1397,28 @@ static int nand_create_badblock_pattern(struct nand_chip *this) > */ > int nand_create_bbt(struct nand_chip *this) > { > + struct mtd_info *mtd = nand_to_mtd(this); > + int (*suspend) (struct mtd_info *) = mtd->_suspend; > + void (*resume) (struct mtd_info *) = mtd->_resume; > int ret; > > + /* > + * The BBT scan logic use the MTD helpers before the MTD layer had a > + * chance to initialize the device, and that leads to issues when > + * accessing the uninitialized suspend lock. Let's temporarily set the > + * suspend/resume hooks to NULL to skip the lock acquire/release step. > + * > + * FIXME: This is an ugly hack, so please don't copy this pattern to > + * other MTD implementations. The proper fix would be to implement a > + * generic BBT scan logic at the NAND level that's not using any of the > + * MTD helpers to access pages. We also might consider doing a two > + * step initialization at the MTD level (mtd_device_init() + > + * mtd_device_register()) so some of the fields are initialized > + * early. > + */ > + mtd->_suspend = NULL; > + mtd->_resume = NULL; > + > /* Is a flash based bad block table requested? */ > if (this->bbt_options & NAND_BBT_USE_FLASH) { > /* Use the default pattern descriptors */ > @@ -1422,7 +1442,13 @@ int nand_create_bbt(struct nand_chip *this) > return ret; > } > > - return nand_scan_bbt(this, this->badblock_pattern); > + ret = nand_scan_bbt(this, this->badblock_pattern); > + > + /* Restore the suspend/resume hooks. */ > + mtd->_suspend = suspend; > + mtd->_resume = resume; > + > + return ret; > } > EXPORT_SYMBOL(nand_create_bbt); >