Re: [PATCH v4 01/44] dma-mapping: Use unsigned long for dma_attrs

[Christoph Hellwig]

On Fri, Jun 10, 2016 at 04:49:47PM +0200, Luis R. Rodriguez wrote:
> Do we not expect the number of argument to grow ? This "cleanup" would
> do away with such possibilities, and then require adding the API later,
> and this requiring a full set of collateral evolutions again when this
> is needed. What was the original motivation for using this instead of
> the approach you are suggesting ?

We still got plenty of space for attrs.  If you're worried about running
out of 32 flags we could do a dma_attrs_t typedef that we could swich
to a u64.  That would have another advantage in that we could add a
__bitwise sparse annotation to avoid people passing the wrong kind of
flags.