About SECTION_SIZE_BITS for Sparsemem

[Russell King - ARM Linux]

On Tue, Jul 13, 2010 at 10:53:24AM +0900, KAMEZAWA Hiroyuki wrote:
> yet another _very easy_ solution is, define pfn_valid() as following.

We have a perfectly good and efficient pfn_valid() implementation which'll
work no matter what memory model is chosen - we don't need to invent other
solutions.  But as sparsemem always provides its own pfn_valid() and is
not overridable...

Maybe the answer _is_ to make it overridable.