From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752058AbeBIM71 (ORCPT ); Fri, 9 Feb 2018 07:59:27 -0500 Received: from mx2.suse.de ([195.135.220.15]:46558 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750997AbeBIM7Z (ORCPT ); Fri, 9 Feb 2018 07:59:25 -0500 Date: Fri, 9 Feb 2018 13:59:22 +0100 (CET) From: Miroslav Benes To: Petr Mladek cc: Jiri Kosina , Josh Poimboeuf , Jason Baron , Joe Lawrence , Jessica Yu , Evgenii Shatokhin , live-patching@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v7 5/7] livepatch: Support separate list for replaced patches. In-Reply-To: <20180206103424.10829-6-pmladek@suse.com> Message-ID: References: <20180206103424.10829-1-pmladek@suse.com> <20180206103424.10829-6-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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 6 Feb 2018, Petr Mladek wrote: > From: Jason Baron > > We are going to add a feature called atomic replace. It will allow to > create a patch that would replace all already registered patches. > > The replaced patches will stay registered because they are typically > unregistered by some package uninstall scripts. But we will remove > these patches from @klp_patches list to keep the enabled patch > on the bottom of the stack. Otherwise, we would need to implement > rather complex logic for moving the patches on the stack. Also > it would complicate implementation of the atomic replace feature. > It is not worth it. > > As a result, we will have patches that are registered but that > are not longer usable. Let's get prepared for this and use > a better descriptive name for klp_is_patch_registered() function. > > Also create separate list for the replaced patches and allow to > unregister them. Alternative solution would be to add a flag > into struct klp_patch. Note that patch->kobj.state_initialized > is not safe because it can be cleared outside klp_mutex. > > This patch does not change the existing behavior. > > Signed-off-by: Jason Baron > [pmladek@suse.com: Split and renamed klp_is_patch_usable()] > Signed-off-by: Petr Mladek > Cc: Josh Poimboeuf > Cc: Jessica Yu > Cc: Jiri Kosina > Cc: Miroslav Benes > --- > kernel/livepatch/core.c | 30 ++++++++++++++++++++++++------ > 1 file changed, 24 insertions(+), 6 deletions(-) > > diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c > index fccb603942f1..11632fe8716a 100644 > --- a/kernel/livepatch/core.c > +++ b/kernel/livepatch/core.c > @@ -47,6 +47,13 @@ DEFINE_MUTEX(klp_mutex); > > static LIST_HEAD(klp_patches); > > +/* > + * List of 'replaced' patches that have been replaced by a patch that has the > + * 'replace' bit set. When they are added to this list, they are disabled and > + * can not be re-enabled, but they can be unregistered(). > + */ > +LIST_HEAD(klp_replaced_patches); It should be static, I think. It is used only in kernel/livepatch/core.c. And sparse complains about it. With that fixed Acked-by: Miroslav Benes Miroslav