Date: Thu, 17 Mar 2016 08:24:56 +0100
From: Ingo Molnar <mingo@kernel.org>
To: Rik van Riel <riel@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>,
        Olu Ogunbowale <Olu.Ogunbowale@imgtec.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Michel Lespinasse <walken@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Hugh Dickins <hughd@google.com>, Russell King <linux@arm.linux.org.uk>,
        Ralf Baechle <ralf@linux-mips.org>, Paul Mundt <lethal@linux-sh.org>,
        "David S. Miller" <davem@davemloft.net>,
        Chris Metcalf <cmetcalf@tilera.com>, Ingo Molnar <mingo@elte.hu>,
        Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH] mm: Export symbols unmapped_area() &
 unmapped_area_topdown()
Message-ID: <20160317072456.GA2522@gmail.com>
References: <1458148234-4456-1-git-send-email-Olu.Ogunbowale@imgtec.com>
 <1458148234-4456-2-git-send-email-Olu.Ogunbowale@imgtec.com>
 <20160316203657.GA29061@infradead.org>
 <1458162041.14723.32.camel@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <1458162041.14723.32.camel@redhat.com>
User-Agent: Mutt/1.5.23 (2014-03-12)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1028
Lines: 30


* Rik van Riel <riel@redhat.com> wrote:

> On Wed, 2016-03-16 at 13:36 -0700, Christoph Hellwig wrote:
> > On Wed, Mar 16, 2016 at 05:10:34PM +0000, Olu Ogunbowale wrote:
> > > 
> > > From: Olujide Ogunbowale <Olu.Ogunbowale@imgtec.com>
> > > 
> > > Export the memory management functions, unmapped_area() &
> > > unmapped_area_topdown(), as GPL symbols; this allows the kernel to
> > > better support process address space mirroring on both CPU and
> > > device
> > > for out-of-tree drivers by allowing the use of vm_unmapped_area()
> > > in a
> > > driver's file operation get_unmapped_area().
> > No new exports without in-tree drivers.??How about you get started
> > to get your drives into the tree first?
> 
> The drivers appear to require the HMM framework though,
> which people are also reluctant to merge without the
> drivers.
> 
> How do we get past this chicken & egg situation?

Submit the export together with the drivers for review and Cc: VM folks - it all 
looks pretty small on the VM side.

Thanks,

	Ingo