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Date:   Wed, 20 Mar 2019 23:39:10 +0300
From:   Alexey Dobriyan <adobriyan@gmail.com>
To:     Daniel Colascione <dancol@google.com>
Cc:     Christian Brauner <christian@brauner.io>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Joel Fernandes <joel@joelfernandes.org>,
        Andy Lutomirski <luto@kernel.org>
Subject: Re: pidfd design
Message-ID: <20190320203910.GA2842@avx2>
References: <20190320200702.GA27111@avx2>
 <CAKOZuespjOTbaTDbgQLo=7PXTE-nYCLy7k=s+RJh_GpZ_5gwgg@mail.gmail.com>
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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.