provide more common DMA API functions V2

[Christoph Hellwig]

On Mon, Aug 17, 2015 at 02:24:29PM -0700, Andrew Morton wrote:
> 110254 bytes saved, shrinking the kernel by a whopping 0.17%. 
> Thoughts?

Sounds fine to me.

> 
> I'll merge these 5 patches for 4.3.  That means I'll release them into
> linux-next after 4.2 is released.

So you only add for-4.3 code to -next after 4.2 is odd?  Isn't thast the
wrong way around?