a saner API for allocating DMA addressable pages

[Christoph Hellwig]

On Tue, Aug 25, 2020 at 01:30:41PM +0200, Marek Szyprowski wrote:
> I really wonder what is the difference between this new API and 
> alloc_pages(GFP_DMA, n). Is this API really needed? I thought that this 
> is legacy thing to be removed one day...

The difference is that the pages returned are guranteed to be addressable
by the devie.  This is a very important difference that matters for
a lot of use cases.