linux-kernel - Re: [RFC PATCH] livepatch: allow removal of a disabled patch

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Message-ID: <alpine.LNX.2.00.1606010112020.31937@cbobk.fhfr.pm>
Date:	Wed, 1 Jun 2016 01:13:36 +0200 (CEST)
From:	Jiri Kosina <jikos@...nel.org>
To:	Miroslav Benes <mbenes@...e.cz>
cc:	Josh Poimboeuf <jpoimboe@...hat.com>, jeyu@...hat.com,
	pmladek@...e.com, jslaby@...e.cz, live-patching@...r.kernel.org,
	linux-kernel@...r.kernel.org, huawei.libin@...wei.com,
	minfei.huang@...oo.com
Subject: Re: [RFC PATCH] livepatch: allow removal of a disabled patch

On Tue, 3 May 2016, Miroslav Benes wrote:

> > > Currently we do not allow patch module to unload since there is no
> > > method to determine if a task is still running in the patched code.
> > > 
> > > The consistency model gives us the way because when the patching
> > > finishes we know that all tasks were marked as safe to call a new
> > > patched function. Thus every new call to the function calls the new
> > > patched code and at the same time no task can be somewhere in the old
> > > code, because it had to leave that code to be marked as safe.
> > > 
> > > We can safely let the patch module go after that.
> > 
> > I found this a little confusing because it talks about patching, whereas
> > we really want to remove the patch module after _unpatching_ it.
> 
> You're right. I'll rephrase that.

Now that it's been settled that this way (completion) is the way to go, 
could you please incorporate the feedback (and persumably also add Acks 
from Josh and Jessica) and send me v2?

Thanks,

-- 
Jiri Kosina
SUSE Labs