[RFC PATCH 1/2] drivers: dma-coherent: Introduce interface for default DMA pool

[Christoph Hellwig]

On Mon, Jul 17, 2017 at 09:58:04AM +0100, Vladimir Murzin wrote:
> Christoph noticed [1] that default DMA pool in current form overload
> the DMA coherent infrastructure. In reply, Robin suggested to split
> the per-device vs. global pool interfaces, so allocation/release from
> default DMA pool is driven by dma ops implementation.
> 
> This patch implements Robin's idea and provide interface to
> allocate/release/mmap the default/global DMA pool.
> 
> [1] https://lkml.org/lkml/2017/7/7/370
> [2] https://lkml.org/lkml/2017/7/7/431
> 
> Suggested-by: Robin Murphy <robin.murphy at arm.com>
> Signed-off-by: Vladimir Murzin <vladimir.murzin at arm.com>

This looks good to me.  I'd just rename the existin *_from_coherent
routines to *_from_dev_coherent.