From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965519AbbD0WxO (ORCPT ); Mon, 27 Apr 2015 18:53:14 -0400 Received: from mail-pd0-f181.google.com ([209.85.192.181]:35159 "EHLO mail-pd0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965092AbbD0WxM (ORCPT ); Mon, 27 Apr 2015 18:53:12 -0400 Date: Mon, 27 Apr 2015 15:53:07 -0700 From: Brian Norris To: Richard Weinberger Cc: Ben Shelton , linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, dwmw2@infradead.org, punnaiah.choudary.kalluri@xilinx.com Subject: Re: [PATCH 1/3] mtd: nand: Add on-die ECC support Message-ID: <20150427225307.GC32500@ld-irv-0074> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <553EBB4A.1040905@nod.at> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 sure if 4.7 is unique. But hey, others are doing this, so why not join the crowd. e.g.: include/asm-generic/pgtable.h-567-#ifndef __HAVE_ARCH_PMD_WRITE include/asm-generic/pgtable.h-568-static inline int pmd_write(pmd_t pmd) include/asm-generic/pgtable.h-569-{ include/asm-generic/pgtable.h:570: BUG(); include/asm-generic/pgtable.h-571- return 0; include/asm-generic/pgtable.h-572-} include/asm-generic/pgtable.h-573-#endif /* __HAVE_ARCH_PMD_WRITE */ From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pd0-x236.google.com ([2607:f8b0:400e:c02::236]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1YmruB-0002GB-5q for linux-mtd@lists.infradead.org; Mon, 27 Apr 2015 22:53:36 +0000 Received: by pdbnk13 with SMTP id nk13so143396746pdb.0 for ; Mon, 27 Apr 2015 15:53:12 -0700 (PDT) Date: Mon, 27 Apr 2015 15:53:07 -0700 From: Brian Norris To: Richard Weinberger Subject: Re: [PATCH 1/3] mtd: nand: Add on-die ECC support Message-ID: <20150427225307.GC32500@ld-irv-0074> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <553EBB4A.1040905@nod.at> Cc: Ben Shelton , dwmw2@infradead.org, linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, punnaiah.choudary.kalluri@xilinx.com List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 sure if 4.7 is unique. But hey, others are doing this, so why not join the crowd. e.g.: include/asm-generic/pgtable.h-567-#ifndef __HAVE_ARCH_PMD_WRITE include/asm-generic/pgtable.h-568-static inline int pmd_write(pmd_t pmd) include/asm-generic/pgtable.h-569-{ include/asm-generic/pgtable.h:570: BUG(); include/asm-generic/pgtable.h-571- return 0; include/asm-generic/pgtable.h-572-} include/asm-generic/pgtable.h-573-#endif /* __HAVE_ARCH_PMD_WRITE */