cleanup the walk_page_range interface

[Christoph Hellwig]

Hi all,

this series is based on a patch from Linus to split the callbacks
passed to walk_page_range and walk_page_vma into a separate structure
that can be marked const, with various cleanups from me on top.

Note that both Thomas and Steven have series touching this area pending,
and there are a couple consumer in flux too - the hmm tree already
conflicts with this series, and I have potential dma changes on top of
the consumers in Thomas and Steven's series, so we'll probably need a
git tree similar to the hmm one to synchronize these updates.


This series is also available as a git tre here:

    git://git.infradead.org/users/hch/misc.git pagewalk-cleanup

Gitweb:

    http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/pagewalk-cleanup


Diffstat:

    14 files changed, 285 insertions(+), 278 deletions(-)