dev_pagemap related cleanups v3

From: Christoph Hellwig
Date: Wed Jun 26 2019 - 08:29:36 EST


Hi Dan, JÃrÃme 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

Note: this series is on top of Linux 5.2-rc5 and has some minor
conflicts with the hmm tree that are easy to resolve.

Diffstat summary:

32 files changed, 361 insertions(+), 1012 deletions(-)

Git tree:

git://git.infradead.org/users/hch/misc.git hmm-devmem-cleanup.3

Gitweb:

http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/hmm-devmem-cleanup.3


Changes since v2:
- fix nvdimm kunit build
- add a new memory type for device dax
- fix a few issues in intermediate patches that didn't show up in the end
result
- incorporate feedback from Michal Hocko, including killing of
the DEVICE_PUBLIC memory type entirely

Changes since v1:
- rebase
- also switch p2pdma to the internal refcount
- add type checking for pgmap->type
- rename the migrate method to migrate_to_ram
- cleanup the altmap_valid flag
- various tidbits from the reviews