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=-6.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 D2D88C4320A for ; Thu, 29 Jul 2021 14:08:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B98126054E for ; Thu, 29 Jul 2021 14:08:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239068AbhG2OIY (ORCPT ); Thu, 29 Jul 2021 10:08:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:50198 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238537AbhG2OBF (ORCPT ); Thu, 29 Jul 2021 10:01:05 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id D2DFD60F4B; Thu, 29 Jul 2021 14:00:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1627567237; bh=zpaHIP0trcuo0pKfQIns0Olh+uBBj4ssUvGd0sEYq6Q=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=MklJTt6j1cy+MWLSeVkjK9Vb753BQLTmRSsDJ+cjTnpXHvcuApz+YoHMS9RTO+kdI 6LdQ6G60UnCRL6SolGgwnIr30H0URTxF3xtYIOkDSYkyX1ZQiWbFbiqQjURYWnb/w/ TEszwDmuPsyvhlwJPhnl6EEDbtwkOs1Bbo/QZwZc= Date: Thu, 29 Jul 2021 15:59:02 +0200 From: Greg KH To: qiaoyanbo_310 Cc: rafael@kernel.org, linux-kernel@vger.kernel.org Subject: Re: Re: [PATCH] kobject: kobject_add_internal cleanup Message-ID: References: <20210727143212.39142-1-qiaoyanbo_310@163.com> <3be7ce57.62f6.17af280a47f.Coremail.qiaoyanbo_310@163.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <3be7ce57.62f6.17af280a47f.Coremail.qiaoyanbo_310@163.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org A: http://en.wikipedia.org/wiki/Top_post Q: Were do I find info about this thing called top-posting? A: Because it messes up the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing in e-mail? A: No. Q: Should I include quotations after my reply? http://daringfireball.net/2007/07/on_top On Thu, Jul 29, 2021 at 09:42:34PM +0800, qiaoyanbo_310 wrote: > Hi Greg k-h, > > > First at all, there is my mistake about From line different with Sign off line. They all should be "Qiao Yanbo". Great, please fix that up. > Secondly, the problem this patch wants to solve is： In this function, the parent variable is first called "kobject_get (kobj->parent) " assignment. When the parent is not null, the just obtained parent is assigned back to "kobj - > parent", which is meaningless. Actually, "kobj->kset->kobj" will be assigned to "kobj->parent" only when the parent is NULL. So this patch solves the problem of meaningless assignment. Why is this a problem? What bug is this solving? Is the code somehow now faster or smaller that can be measured? > Finally , I tested this patch and didn't see any additional problems in my environment. > > > Here is the original code snippet. I hope you can understand my idea. > ======================================================= > parent = kobject_get(kobj->parent); > > > /* join kset if set, use it as parent if we do not already have one */ > if (kobj->kset) { > if (!parent) > parent = kobject_get(&kobj->kset->kobj); > kobj_kset_join(kobj); > kobj->parent = parent; I do not see a bug with this code, what is wrong with it? thanks, greg k-h