Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753280AbbD0XPz (ORCPT ); Mon, 27 Apr 2015 19:15:55 -0400 Received: from a.ns.miles-group.at ([95.130.255.143]:65275 "EHLO radon.swed.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753100AbbD0XPw (ORCPT ); Mon, 27 Apr 2015 19:15:52 -0400 Message-ID: <553EC325.6060401@nod.at> Date: Tue, 28 Apr 2015 01:15:49 +0200 From: Richard Weinberger User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Brian Norris CC: Ben Shelton , "linux-mtd@lists.infradead.org" , Linux Kernel , David Woodhouse , Punnaiah Choudary Kalluri Subject: Re: [PATCH 1/3] mtd: nand: Add on-die ECC support References: <1427292151-3835-1-git-send-email-richard@nod.at> <1427292151-3835-2-git-send-email-richard@nod.at> <20150427213558.GA22780@bshelton-desktop> <553EB5E4.3050309@nod.at> <20150427223630.GA11721@bshelton-desktop> <553EBB4A.1040905@nod.at> <20150427225307.GC32500@ld-irv-0074> <553EBEDD.9050204@nod.at> In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2414 Lines: 55 Am 28.04.2015 um 01:10 schrieb Brian Norris: > On Mon, Apr 27, 2015 at 3:57 PM, Richard Weinberger wrote: >> Am 28.04.2015 um 00:53 schrieb Brian Norris: >>> On Tue, Apr 28, 2015 at 12:42:18AM +0200, Richard Weinberger wrote: >>>> Am 28.04.2015 um 00:36 schrieb Ben Shelton: >>>>>>> When I build this without CONFIG_MTD_NAND_ECC_ON_DIE enabled, I get the >>>>>>> following warning here: >>>>>>> >>>>>>> In file included from drivers/mtd/nand/nand_base.c:46:0: >>>>>>> include/linux/mtd/nand_ondie.h: In function 'nand_read_subpage_on_die': >>>>>>> include/linux/mtd/nand_ondie.h:28:1: warning: no return statement in function returning non-void [-Wreturn-type] >>>>>>> include/linux/mtd/nand_ondie.h: In function 'nand_read_page_on_die': >>>>>>> include/linux/mtd/nand_ondie.h:34:1: warning: no return statement in function returning non-void [-Wreturn-type] >>>>>>> >>>>>>> Perhaps return an error code here, even though you'll never get past the BUG()? >>>>>> >>>>>> What gcc is this? >>>>>> gcc 4.8 here does not warn, I thought it is smart enough that this function does never >>>>>> return. Can it be that your .config has CONFIG_BUG=n? >>>>>> Anyway, this functions clearly needs a return statement. :) >>>>> >>>>> gcc 4.7.2, and you are correct that I had CONFIG_BUG off. :) >>>> >>>> Yeah, just noticed that BUG() with CONFIG_BUG=n does not have >>>> a nonreturn attribute. So, gcc cannot know... >>> >>> But it's an obvious infinite loop... all of my toolchains (4.2, 4.5, >>> 4.6, 4.8) are able to compile this without complaining (gcc -Wall): >>> >>> int test() { do { } while (1); } >> >> Not here. gcc 4.8 warns on that. >> As soon I add __attribute__ ((noreturn)) it does not longer complain. > > Huh? Maybe I have a crazy modified gcc. > > $ gcc --version > gcc (Ubuntu 4.8.2-19ubuntu1) 4.8.2 > Copyright (C) 2013 Free Software Foundation, Inc. > This is free software; see the source for copying conditions. There is NO > warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. > > $ gcc -Wall -Wextra -c a.c > $ cat a.c > int test() { do {} while (1); } Make test static and gcc will warn. Thanks, //richard -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/