Re: [PATCH 1/6] procfs: Kill BKL in llseek on proc base

From: Frederic Weisbecker <fweisbec@gmail.com>
To: Alexey Dobriyan <adobriyan@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Arnd Bergmann <arnd@arndb.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	John Kacur <jkacur@redhat.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
	Al Viro <viro@zeniv.linux.org.uk>, Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH 1/6] procfs: Kill BKL in llseek on proc base
Date: Tue, 30 Mar 2010 08:50:48 +0200	[thread overview]
Message-ID: <20100330065046.GA22419@nowhere> (raw)
In-Reply-To: <b6fcc0a1003292340w3452b4c3wc25282811365c7ef@mail.gmail.com>

On Tue, Mar 30, 2010 at 09:40:24AM +0300, Alexey Dobriyan wrote:
> On Tue, Mar 30, 2010 at 9:20 AM, Frederic Weisbecker <fweisbec@gmail.com> wrote:
> > --- a/fs/proc/base.c
> > +++ b/fs/proc/base.c
> > @@ -728,6 +728,7 @@ out_no_task:
> >
> >  static const struct file_operations proc_info_file_operations = {
> >        .read           = proc_info_read,
> > +       .llseek         = generic_file_llseek,
> 
> There is no warning for default default_llseek case.
> This should be done same way as proc ioctls.

I don't think we should. We have overriden the llseek for
the procfs users located in the proc core (just fs/proc)
but we haven't touched all of the external users, and since
there are hundreds of them, I guess a lot don't implement
llseek.

We would need to first override those that are visible upstream
and warn for the further ones after this step only.