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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 E97CBC43387 for ; Wed, 9 Jan 2019 14:35:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B72CC2070B for ; Wed, 9 Jan 2019 14:35:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731403AbfAIOfw (ORCPT ); Wed, 9 Jan 2019 09:35:52 -0500 Received: from mx2.suse.de ([195.135.220.15]:33886 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729829AbfAIOfw (ORCPT ); Wed, 9 Jan 2019 09:35:52 -0500 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 2B128AD4C; Wed, 9 Jan 2019 14:35:51 +0000 (UTC) Date: Wed, 9 Jan 2019 15:35:49 +0100 (CET) From: Miroslav Benes To: Petr Mladek cc: Jiri Kosina , Josh Poimboeuf , Jason Baron , Joe Lawrence , Evgenii Shatokhin , live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, Jessica Yu Subject: Re: [PATCH v15 03/11] livepatch: Consolidate klp_free functions In-Reply-To: <20190109124329.21991-4-pmladek@suse.com> Message-ID: References: <20190109124329.21991-1-pmladek@suse.com> <20190109124329.21991-4-pmladek@suse.com> User-Agent: Alpine 2.21 (LSU 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 9 Jan 2019, Petr Mladek wrote: > The code for freeing livepatch structures is a bit scattered and tricky: > > + direct calls to klp_free_*_limited() and kobject_put() are > used to release partially initialized objects > > + klp_free_patch() removes the patch from the public list > and releases all objects except for patch->kobj > > + object_put(&patch->kobj) and the related wait_for_completion() > are called directly outside klp_mutex; this code is duplicated; > > Now, we are going to remove the registration stage to simplify the API > and the code. This would require handling more situations in > klp_enable_patch() error paths. > > More importantly, we are going to add a feature called atomic replace. > It will need to dynamically create func and object structures. We will > want to reuse the existing init() and free() functions. This would > create even more error path scenarios. > > This patch implements more straightforward free functions: > > + checks kobj_added flag instead of @limit[*] > > + initializes patch->list early so that the check for empty list > always works > > + The action(s) that has to be done outside klp_mutex are done > in separate klp_free_patch_finish() function. It waits only > when patch->kobj was really released via the _start() part. > > The patch does not change the existing behavior. > > [*] We need our own flag to track that the kobject was successfully > added to the hierarchy. Note that kobj.state_initialized only > indicates that kobject has been initialized, not whether is has > been added (and needs to be removed on cleanup). > > Signed-off-by: Petr Mladek > Cc: Josh Poimboeuf > Cc: Miroslav Benes > Cc: Jessica Yu > Cc: Jiri Kosina > Cc: Jason Baron Acked-by: Miroslav Benes Miroslav