From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753569Ab2CIXJc (ORCPT ); Fri, 9 Mar 2012 18:09:32 -0500 Received: from avon.wwwdotorg.org ([70.85.31.133]:59833 "EHLO avon.wwwdotorg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751077Ab2CIXJa (ORCPT ); Fri, 9 Mar 2012 18:09:30 -0500 Message-ID: <4F5A8DA7.5070900@wwwdotorg.org> Date: Fri, 09 Mar 2012 16:09:27 -0700 From: Stephen Warren User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.23) Gecko/20110921 Thunderbird/3.1.15 MIME-Version: 1.0 To: Paul Gortmaker CC: Linus Walleij , linux-kernel@vger.kernel.org Subject: Re: [PATCH] pinctrl: Include to prevent compile errors References: <1331324305-1649-1-git-send-email-swarren@wwwdotorg.org> <20120309203207.GB10835@windriver.com> <4F5A6B6B.50703@wwwdotorg.org> In-Reply-To: X-Enigmail-Version: 1.1.2 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/09/2012 02:29 PM, Paul Gortmaker wrote: > On Fri, Mar 9, 2012 at 3:43 PM, Stephen Warren wrote: >> On 03/09/2012 01:32 PM, Paul Gortmaker wrote: >>> [[PATCH] pinctrl: Include to prevent compile errors] On 09/03/2012 (Fri 13:18) Stephen Warren wrote: >>> >>>> Macros in call ARRAY_SIZE(), the definition of >>>> which eventually calls BUILD_BUG_ON_ZERO(), which is defined in >>>> . Include that so that every .c file using the pinctrl macros >>>> doesn't have to do that itself. >>> >>> Which C files are failing? The approach was to be adding it only >>> for headers with static inlines which use it, and add it to C files >>> that are actually *deploying* the macros. >> >> For me, the files that are failing haven't been committed upstream yet; >> I expect them to be very soon after the 3.4 merge window completes. >> >> However, I expect you'll see this issue with arch/arm/mach-u300/core.c, >> since it uses the same macros defined in pinctrl/machine.h that cause >> the problem for me, unless one of the include files there picks up bug.h >> already. >> >> As a general statement though, once pinctrl becomes more widely adopted, >> I expect to see many files start to use macros from pinctrl/machine.h, >> and hence implicitly use ARRAY_SIZE(), and hence even more implicitly >> depend on linux/bug.h. I don't think it's at all reasonable to force the >> author of every one of those files to track down 3 or 4 levels of header >> file dependencies to find that they need linux/bug.h even though they >> make no direct use of its features, when it's known that almost any user >> of pinctrl/machine.h is going to hit this issue. > > There was a similar discussion before, where there was concern over > "every one of those files" but in the end the number is a fraction of > a percent. There is no harm in the author knowing they are making > _use_ of BUG stuff -- in fact if you happened to be trying to write some > fault tolerant code, you might really be glad to know, so you could take > steps to avoid it.... The primary purpose for pinctrl/machine.h is files that define a certain data structure that will almost invariably be initialized using the macros in that header. Size those macros use ARRAY_SIZE, every one of those .c files will require bug.h. There are 1 or 2 files in drivers/pinctrl that include pinctrl/machine.h solely for the data structure definitions or function prototypes, and won't use those macros, but those are the exception rather than the rule for this one header at least.