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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0C352C4167B for ; Thu, 7 Dec 2023 12:52:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232528AbjLGMwn (ORCPT ); Thu, 7 Dec 2023 07:52:43 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43638 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232541AbjLGMwl (ORCPT ); Thu, 7 Dec 2023 07:52:41 -0500 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 588E9122; Thu, 7 Dec 2023 04:52:47 -0800 (PST) X-IronPort-AV: E=McAfee;i="6600,9927,10916"; a="398105685" X-IronPort-AV: E=Sophos;i="6.04,256,1695711600"; d="scan'208";a="398105685" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Dec 2023 04:52:46 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10916"; a="771724258" X-IronPort-AV: E=Sophos;i="6.04,256,1695711600"; d="scan'208";a="771724258" Received: from smile.fi.intel.com ([10.237.72.54]) by orsmga002.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Dec 2023 04:52:44 -0800 Received: from andy by smile.fi.intel.com with local (Exim 4.97) (envelope-from ) id 1rBDrs-00000002bPB-40QR; Thu, 07 Dec 2023 14:52:40 +0200 Date: Thu, 7 Dec 2023 14:52:40 +0200 From: Andy Shevchenko To: Al Viro Cc: Nick Desaulniers , tanzirh@google.com, Kees Cook , linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org, Nick DeSaulniers , Andrew Morton , llvm@lists.linux.dev Subject: Re: [PATCH] lib/string: shrink lib/string.i via IWYU Message-ID: References: <20231205-libstringheader-v1-1-7f9c573053a7@gmail.com> <20231205213807.GE1674809@ZenIV> <20231205221521.GH1674809@ZenIV> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20231205221521.GH1674809@ZenIV> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 05, 2023 at 10:15:21PM +0000, Al Viro wrote: > On Wed, Dec 06, 2023 at 12:01:56AM +0200, Andy Shevchenko wrote: > > On Tue, Dec 05, 2023 at 01:51:10PM -0800, Nick Desaulniers wrote: > > > On Tue, Dec 5, 2023 at 1:38 PM Al Viro wrote: > > > > On Tue, Dec 05, 2023 at 08:58:53PM +0000, tanzirh@google.com wrote: ... > > > > > IWYU is implemented using the IWYUScripts github repository which is a tool that is > > > > > currently undergoing development. These changes seek to improve build times. > > > > > > > > > > This change to lib/string.c resulted in a preprocessed size of > > > > > lib/string.i from 26371 lines to 5232 lines (-80%). > > > > > > > > It also breeds includes of asm/*.h, by the look of the output, which is > > > > not a good thing in general ;-/ E.g. #include *anywhere* > > > > outside of linux/uaccess.h is a bad idea. > > > > > > It's not clear to me when it's ok to #include . Is there a > > > convention here that I'm missing? > > > > The mandatory ones can be used, but not all of them. > > In some cases you even must include asm and not linux > > (unaligned.h, byteorder.h, maybe others...). > > > > As I told, it comes with experience, we lack of the > > respective documentation (or file which is good for > > automation checks, like with IWYU). > > It would certainly be nice to have such information in the tree; > "where should I pick $SYMBOL from?" is something one needs to > find out often enough. To a large extent it's covered by "where > in include/*.h do we have it defined?", but that's not all there > is to it. E.g. "get_user() => use linux/uaccess.h". > > There's also stuff like "$SYMBOL should not be used outside of arch/* > and include/*, better use $OTHER_SYMBOL", etc. Precisely! That's what many developers will benefit from! -- With Best Regards, Andy Shevchenko