dev_pagemap related cleanups

[Christoph Hellwig <hch@xxxxxx>]

Hi Dan, Jérôme and Jason,

below is a series that cleans up the dev_pagemap interface so that
it is more easily usable, which removes the need to wrap it in hmm
and thus allowing to kill a lot of code

Diffstat:

 22 files changed, 245 insertions(+), 802 deletions(-)

Git tree:

    git://git.infradead.org/users/hch/misc.git hmm-devmem-cleanup

Gitweb:

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