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Date:   Fri, 4 Dec 2020 10:20:59 -0800
From:   Will McVicker <willmcvicker@google.com>
To:     Christoph Hellwig <hch@infradead.org>
Cc:     Jessica Yu <jeyu@kernel.org>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Michal Marek <michal.lkml@markovi.net>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Saravana Kannan <saravanak@google.com>,
        linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org,
        kernel-team@android.com
Subject: Re: [PATCH v2 0/2] Adds support to capture module's SCM version
Message-ID: <X8p+CylIWycDff8w@google.com>
References: <CAGETcx8unBFUHxM67VdOoaWRENGXYoc4qWq2Oir=2rUyJ7F5nA@mail.gmail.com>
 <20201125010541.309848-1-willmcvicker@google.com>
 <X8mEhIeYeMjZc/+7@google.com>
 <20201204075159.GA29752@infradead.org>
 <X8p8ZK1sXQ2E7hSA@google.com>
 <20201204181808.GA26478@infradead.org>
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On Fri, Dec 04, 2020 at 06:18:08PM +0000, Christoph Hellwig wrote:
> On Fri, Dec 04, 2020 at 10:13:56AM -0800, Will McVicker wrote:
> > On Fri, Dec 04, 2020 at 07:51:59AM +0000, Christoph Hellwig wrote:
> > > I think your decription still shows absolutely no benefit for the
> > > kernel, so I'not sure why anyone would want to waste time on this.
> > Hi Christoph,
> > 
> > Did you get a chance to read my earlier responses regarding the uses for
> > in-tree modules?
> > 
> > The biggest benefit for the upstream community is being about to get the SCM
> > version for *any* module (including in-tree modules) in the initramfs via the
> > sysfs node. Currently there is no way to do that and there is no guarantee that
> 
> That assumes the SCM version of a module has any kind of meaning for
> an in-tree module.  Which it doesn't.  If you care about the SCM version
> of an in-tree module the only thing we need is one single global sysfs
> file.
Why doesn't it have meaning? With MODVERSIONS, you are able to update in-tree
kernel modules independently of the kernel. That means you can update as many
in-tree modules as you want which would create many different SCM versions (1
per every module update). Also you can update the kernel independently of the
in-tree modules introducing another SCM version.

--Will