Pull powerpc mremap fix from Ben Herrenschmidt:
"This is the patch that I had sent after -rc8 and which we decided to
wait before merging. It's based on a different tree than my -next
branch (it needs some pre-reqs that were in -rc4 or so while my -next
is based on -rc1) so I left it as a separate branch for your to pull.
It's identical to the request I did 2 or 3 weeks back.
This fixes crashes in mremap with THP on powerpc.
The fix however requires a small change in the generic code. It moves
a condition into a helper we can override from the arch which is
harmless, but it *also* slightly changes the order of the set_pmd and
the withdraw & deposit, which should be fine according to Kirill (who
wrote that code) but I agree -rc8 is a bit late...
It was acked by Kirill and Andrew told me to just merge it via powerpc"
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
powerpc/thp: Fix crash on mremap
d12de1ef5e