Re: [PATCH] mm: Export symbols unmapped_area() & unmapped_area_topdown()

From: Ingo Molnar
Date: Thu Mar 17 2016 - 03:25:14 EST



* Rik van Riel <riel@xxxxxxxxxx> 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@xxxxxxxxxx>
> > >
> > > 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