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 X-Spam-Level: X-Spam-Status: No, score=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2C2E7C5ACCC for ; Thu, 18 Oct 2018 11:11:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B7DC821479 for ; Thu, 18 Oct 2018 11:11:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B7DC821479 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727733AbeJRTM0 (ORCPT ); Thu, 18 Oct 2018 15:12:26 -0400 Received: from mx2.suse.de ([195.135.220.15]:41952 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726173AbeJRTMZ (ORCPT ); Thu, 18 Oct 2018 15:12:25 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 0B46AAFDB; Thu, 18 Oct 2018 11:11:54 +0000 (UTC) Date: Thu, 18 Oct 2018 13:11:53 +0200 From: Petr Mladek To: Josh Poimboeuf Cc: Jiri Kosina , Miroslav Benes , Jason Baron , Joe Lawrence , Evgenii Shatokhin , live-patching@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v13 02/12] livepatch: Helper macros to define livepatch structures Message-ID: <20181018111153.qcmvidttifi57u45@pathway.suse.cz> References: <20181015123713.25868-1-pmladek@suse.com> <20181015123713.25868-3-pmladek@suse.com> <20181017181756.cy65ujygmf3ulmiz@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181017181756.cy65ujygmf3ulmiz@treble> User-Agent: NeoMutt/20170421 (1.8.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 2018-10-17 13:17:56, Josh Poimboeuf wrote: > On Mon, Oct 15, 2018 at 02:37:03PM +0200, Petr Mladek wrote: > > The definition of struct klp_func might be a bit confusing. > > The original function is defined by name as a string. > > The new function is defined by name as a function pointer > > casted to unsigned long. > > > > This patch adds helper macros that hide the different types. > > The functions are defined just by the name. For example: > > On one hand, these macros are kind of nice, because they do the function > pointer casting for the user. > > On the other hand, they hide the field names, which hurts readability a > bit. For example, it would be easy to accidentally assign the wrong > callback function. I am not a big fan of the macros either. > Also, it's unfortunate that these macros are needed in the first place. > > What if we just change new_addr (and old_addr) to be 'void *'? Then the > macros wouldn't be as useful, and we could just get rid of them. Hmm, I wonder if any change make sense then. The above proposal might just exchange one confusion with another one: + I would expect that a variable called addr is of the type unsigned long + we would need casting when calling ftrace API + .new_addr = function_xxx looks a bit weird and it will be used many times in all livepatch sources. That said I could live with any solution. The livepatch code is complicated from other reasons. This is only small detail from my (today's ;-) point of view. Best Regards, Petr