Generic IOMMU pooled allocator

[Sowmini Varadhan]

Turned out that I was able to iterate over it, and remove
both the ->cookie_to_index and the ->demap indirection from
iommu_tbl_ops.

That leaves only the odd iommu_flushall() hook, I'm trying
to find the history behind that (needed for sun4u platforms,
afaik, and not sure if there are other ways to achieve this).

Just sent out a new patch-set, which should reach all the 
people/lists on this thread.

If it's possible, it would also help to share any preliminary
code-samples with the iommu_table_ops you folks have in mind.

Please take a look at patchv5, and share your thoughts.

--Sowmini