From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753615AbcGSPoz (ORCPT ); Tue, 19 Jul 2016 11:44:55 -0400 Received: from b.ns.miles-group.at ([95.130.255.144]:44723 "EHLO radon.swed.at" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752473AbcGSPow (ORCPT ); Tue, 19 Jul 2016 11:44:52 -0400 Subject: Re: [PATCH 1/2] mtd: nand: BUG_ON in case of no select_chip and cmd_ctrl To: Andrey Smirnov , linux-mtd@lists.infradead.org References: <1468942904-26464-1-git-send-email-andrew.smirnov@gmail.com> Cc: Boris Brezillon , David Woodhouse , Brian Norris , linux-kernel@vger.kernel.org From: Richard Weinberger Message-ID: <578E4AF0.7090507@nod.at> Date: Tue, 19 Jul 2016 17:44:48 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.7.1 MIME-Version: 1.0 In-Reply-To: <1468942904-26464-1-git-send-email-andrew.smirnov@gmail.com> Content-Type: text/plain; charset=iso-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am 19.07.2016 um 17:41 schrieb Andrey Smirnov: > If no user specified chip->select_chip() function is provided, code in > nand_base.c will automatically set this hook to nand_select_chip(), > which in turn depends on chip->cmd_ctrl() hook being valid. Not > providing both of those functions in NAND controller driver (for example > by mistake) will result in a bit cryptic segfault. Replace it with > explicit BUG_ON statement so it would be obvious what went wrong. > > Signed-off-by: Andrey Smirnov > --- > drivers/mtd/nand/nand_base.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c > index ce7b2ca..57043a6 100644 > --- a/drivers/mtd/nand/nand_base.c > +++ b/drivers/mtd/nand/nand_base.c > @@ -3128,8 +3128,10 @@ static void nand_set_defaults(struct nand_chip *chip, int busw) > if (chip->waitfunc == NULL) > chip->waitfunc = nand_wait; > > - if (!chip->select_chip) > + if (!chip->select_chip) { > + BUG_ON(!chip->cmd_ctrl); Please don't add new BUG_ON() calls. WARN_ON() is good enough to raise the driver developer's attention and won't kill the machine. Thanks, //richard