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 lists.sourceforge.net (lists.sourceforge.net [216.105.38.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DADB8C6379F for ; Tue, 17 Jan 2023 16:43:01 +0000 (UTC) Received: from [127.0.0.1] (helo=sfs-ml-1.v29.lw.sourceforge.com) by sfs-ml-1.v29.lw.sourceforge.com with esmtp (Exim 4.95) (envelope-from ) id 1pHp35-0006mi-9A; Tue, 17 Jan 2023 16:42:58 +0000 Received: from [172.30.20.202] (helo=mx.sourceforge.net) by sfs-ml-1.v29.lw.sourceforge.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1pHp33-0006mb-PF for linux-f2fs-devel@lists.sourceforge.net; Tue, 17 Jan 2023 16:42:56 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; h=Content-Transfer-Encoding:Content-Type:In-Reply-To: From:References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=jBMiC23PuaYE856mBxP4m1QXC3Ppdq8BFbM+KH+7+Eo=; b=g9qUFAUk2MIe776ZCuVc9HN7ml i2nyZMxCxCqv8jtZS3Z5cz1+H746UvwP0KvSn6A6GEdTn1XIPTQPW0DxE6SqcRfrwEnTWZCcjczSe qtyX/mW4cY27+uGoSASpBBZ+Yi1sODwjfXkujR1VeRTUgHW0BHqVSQoJVm0OTOr1N624=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From:References:Cc:To: Subject:MIME-Version:Date:Message-ID:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=jBMiC23PuaYE856mBxP4m1QXC3Ppdq8BFbM+KH+7+Eo=; b=Epaf0XT2UKH/NNghdJcSlYqDYN SD73Z/hq6ONwHOj3proFSlcLXhBaftGlPuQyqjKZbq+jmZXCPbORhyQ9C4YxiTJ8zvtDVMRTZBI2B Zb8wczuP8Q8N4icRjyqHxpXrAsYnVRt6niNTkvq6B23vct2dNiHoDT/RETDc+QdYhaaM=; Received: from outpost1.zedat.fu-berlin.de ([130.133.4.66]) by sfi-mx-2.v28.lw.sourceforge.com with esmtps (TLS1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.95) id 1pHp2z-0001PT-Ah for linux-f2fs-devel@lists.sourceforge.net; Tue, 17 Jan 2023 16:42:56 +0000 Received: from inpost2.zedat.fu-berlin.de ([130.133.4.69]) by outpost.zedat.fu-berlin.de (Exim 4.95) with esmtps (TLS1.3) tls TLS_AES_256_GCM_SHA384 (envelope-from ) id 1pHp2k-001f9B-4y; Tue, 17 Jan 2023 17:42:38 +0100 Received: from p57bd9464.dip0.t-ipconnect.de ([87.189.148.100] helo=[192.168.178.81]) by inpost2.zedat.fu-berlin.de (Exim 4.95) with esmtpsa (TLS1.3) tls TLS_AES_128_GCM_SHA256 (envelope-from ) id 1pHp2j-002q0C-UX; Tue, 17 Jan 2023 17:42:38 +0100 Message-ID: <3800eaa8-a4da-b2f0-da31-6627176cb92e@physik.fu-berlin.de> Date: Tue, 17 Jan 2023 17:42:37 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.6.1 Content-Language: en-US To: Geert Uytterhoeven References: <20221227082932.798359-1-geert@linux-m68k.org> From: John Paul Adrian Glaubitz In-Reply-To: X-Original-Sender: glaubitz@physik.fu-berlin.de X-Originating-IP: 87.189.148.100 X-Headers-End: 1pHp2z-0001PT-Ah Subject: [f2fs-dev] Calculating array sizes in C - was: Re: Build regressions/improvements in v6.2-rc1 X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-xtensa@linux-xtensa.org, linux-sh@vger.kernel.org, linux-wireless@vger.kernel.org, linux-mips@vger.kernel.org, amd-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, Michael Karcher , linux-f2fs-devel@lists.sourceforge.net, linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net Hi Geert! On 1/6/23 16:17, Geert Uytterhoeven wrote: >> I'm not seeing this one, but I am getting this one instead: >> >> In file included from ./arch/sh/include/asm/hw_irq.h:6, >> from ./include/linux/irq.h:596, >> from ./include/asm-generic/hardirq.h:17, >> from ./arch/sh/include/asm/hardirq.h:9, >> from ./include/linux/hardirq.h:11, >> from ./include/linux/interrupt.h:11, >> from ./include/linux/serial_core.h:13, >> from ./include/linux/serial_sci.h:6, >> from arch/sh/kernel/cpu/sh2/setup-sh7619.c:11: >> ./include/linux/sh_intc.h:100:63: error: division 'sizeof (void *) / sizeof (void)' does not compute the number of array elements [-Werror=sizeof-pointer-div] >> 100 | #define _INTC_ARRAY(a) a, __same_type(a, NULL) ? 0 : sizeof(a)/sizeof(*a) >> | ^ >> ./include/linux/sh_intc.h:105:31: note: in expansion of macro '_INTC_ARRAY' >> 105 | _INTC_ARRAY(vectors), _INTC_ARRAY(groups), \ >> | ^~~~~~~~~~~ > > The easiest fix for the latter is to disable CONFIG_WERROR. > Unfortunately I don't know a simple solution to get rid of the warning. I did some research and it seems that what the macro _INT_ARRAY() does with "sizeof(a)/sizeof(*a)" is a commonly used way to calculate array sizes and the kernel has even its own macro for that called ARRAY_SIZE() which Linus asks people to use here [1]. So, I replaced _INTC_ARRAY() with ARRAY_SIZE() (see below), however the kernel's own ARRAY_SIZE() macro triggers the same compiler warning. I'm CC'ing Michael Karcher who has more knowledge on writing proper C code than me and maybe an idea how to fix this warning. Thanks, Adrian > [1] https://lkml.org/lkml/2015/9/3/428 diff --git a/include/linux/sh_intc.h b/include/linux/sh_intc.h index c255273b0281..07a187686a84 100644 --- a/include/linux/sh_intc.h +++ b/include/linux/sh_intc.h @@ -97,14 +97,12 @@ struct intc_hw_desc { unsigned int nr_subgroups; }; -#define _INTC_ARRAY(a) a, __same_type(a, NULL) ? 0 : sizeof(a)/sizeof(*a) - #define INTC_HW_DESC(vectors, groups, mask_regs, \ prio_regs, sense_regs, ack_regs) \ { \ - _INTC_ARRAY(vectors), _INTC_ARRAY(groups), \ - _INTC_ARRAY(mask_regs), _INTC_ARRAY(prio_regs), \ - _INTC_ARRAY(sense_regs), _INTC_ARRAY(ack_regs), \ + ARRAY_SIZE(vectors), ARRAY_SIZE(groups), \ + ARRAY_SIZE(mask_regs), ARRAY_SIZE(prio_regs), \ + ARRAY_SIZE(sense_regs), ARRAY_SIZE(ack_regs), \ } struct intc_desc { -- .''`. John Paul Adrian Glaubitz : :' : Debian Developer `. `' Physicist `- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913 _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel