[PATCH 1/3] x86/pat: export io memory reserve/free api.

[Dave Airlie]

On 18 Oct. 2016 17:23, "Edward O'Callaghan" <funfunctor at folklore1984.net>
wrote:
>
> NACK,
>
> I think you want to use 'iomap_create_wc()' instead to avoid aliasing.

Please explain what can alias here?

Dave.

>
> Kind Regards,
> Edward.
>
> On 10/18/2016 05:13 PM, Dave Airlie wrote:
> > From: Dave Airlie <airlied at redhat.com>
> >
> > These functions are needed for gpu/ttm drivers to reserve the
> > VRAM area as write combined. In a lot of places we don't ioremap
> > but still need to insert pfn from it into a VMA using vm_insert_mixed,
> > but a recent change in mixed insertion means we need to reserve
> > VRAM as WC upfront, so we need these APIs exported.
> >
> > Signed-off-by: Dave Airlie <airlied at redhat.com>
> > ---
> >  arch/x86/mm/pat.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
> > index 170cc4f..5ce2fbb 100644
> > --- a/arch/x86/mm/pat.c
> > +++ b/arch/x86/mm/pat.c
> > @@ -719,6 +719,7 @@ out_free:
> >  out_err:
> >       return ret;
> >  }
> > +EXPORT_SYMBOL(io_reserve_memtype);
> >
> >  /**
> >   * io_free_memtype - Release a memory type mapping for a region of
memory
> > @@ -729,6 +730,7 @@ void io_free_memtype(resource_size_t start,
resource_size_t end)
> >  {
> >       free_memtype(start, end);
> >  }
> > +EXPORT_SYMBOL(io_free_memtype);
> >
> >  pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
> >                               unsigned long size, pgprot_t vma_prot)
> >
>
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