Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Thu, 6 Dec 2018 10:23:40 +0100 (CET)
From:   Miroslav Benes <mbenes@suse.cz>
To:     Petr Mladek <pmladek@suse.com>
cc:     Joe Lawrence <joe.lawrence@redhat.com>,
        Jiri Kosina <jikos@kernel.org>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Jason Baron <jbaron@akamai.com>,
        Evgenii Shatokhin <eshatokhin@virtuozzo.com>,
        live-patching@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v14 05/11] livepatch: Simplify API by removing registration
 step
In-Reply-To: <20181206082814.uyzjw2q4avknhswd@pathway.suse.cz>
Message-ID: <alpine.LSU.2.21.1812061019500.17628@pobox.suse.cz>
References: <20181129094431.7801-1-pmladek@suse.com> <20181129094431.7801-6-pmladek@suse.com> <20181205193253.mhlqj37r4o6ukkhp@redhat.com> <20181206082814.uyzjw2q4avknhswd@pathway.suse.cz>
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

On Thu, 6 Dec 2018, Petr Mladek wrote:

> On Wed 2018-12-05 14:32:53, Joe Lawrence wrote:
> > > diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
> > > index 972520144713..e01dfa3b58d2 100644
> > > --- a/kernel/livepatch/core.c
> > > +++ b/kernel/livepatch/core.c
> > > @@ -45,7 +45,7 @@
> > >   */
> > >  DEFINE_MUTEX(klp_mutex);
> > >  
> > > -/* Registered patches */
> > > +/* Actively used patches. */
> > >  LIST_HEAD(klp_patches);
> > 
> > By itself, this comment makes me wonder if there are un-active and/or
> > un-used patches that I need to worry about.  After this patchset,
> > klp_patches will include patches that have been enabled and those that
> > have been replaced, but the replacement transition is still in progress.  
> > 
> > If that sounds accurate, how about adding to the comment:
> > 
> > /* Actively used patches: enabled or replaced and awaiting transition */
> 
> The replaced patches are not in the list. This is why I used the word
> "actively".

The replaced patches are removed in klp_discard_replaced_patches(), which 
is called from klp_complete_transition(). Joe is right. The patches are in 
the list if a transition is still in progress.

Miroslav
 
> /*
>  * Actively used patches: enabled or in transition. Note that replaced
>  * or disabled patches are not listed even though the related kernel
>  * module still can be loaded.
>  */