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Date:   Wed, 20 Mar 2019 21:47:37 +0100
From:   Christian Brauner <christian@brauner.io>
To:     Alexey Dobriyan <adobriyan@gmail.com>
Cc:     Daniel Colascione <dancol@google.com>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Joel Fernandes <joel@joelfernandes.org>,
        Andy Lutomirski <luto@kernel.org>
Subject: Re: pidfd design
Message-ID: <20190320204736.x4p5m7gxz6rbxlo3@brauner.io>
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On Wed, Mar 20, 2019 at 11:39:10PM +0300, Alexey Dobriyan wrote:
> On Wed, Mar 20, 2019 at 01:14:01PM -0700, Daniel Colascione wrote:
> > On Wed, Mar 20, 2019 at 1:07 PM Alexey Dobriyan <adobriyan@gmail.com> wrote:
> > > > What would be your opinion to having a
> > > > /proc/<pid>/handle
> > > > file instead of having a dirfd.
> > >
> > > This is even worse than depending on PROC_FS. Just for the dependency
> > > pidfd code should be backed out immediately. Forget about /proc.
> > 
> > We already have pidfds, and we've had them since /proc was added ages
> > ago.
> 
> New pidfd code (or whatever the name) should NOT depend on /proc and
> should not interact with VFS at all at any point (other than probably
> being a descriptor on a fake filesystem). The reason is that /proc is
> full of crap and you don't want to spill that into new and hopefully
> properly designed part of new code.

Yes, I agree. That's why I was thinking that translate_pid() is a good
candidate to provide that decoupling.