[PATCH 0/3] dax: require 'struct page' and other fixups

[Dan Williams <dan.j.williams@intel.com>]

Prompted by a recent change to add more protection around setting up
'vm_flags' for a dax vma [1], rework the implementation to remove the
requirement to set VM_MIXEDMAP and VM_HUGEPAGE.

VM_MIXEDMAP is used by dax to direct mm paths like vm_normal_page() that
the memory page it is dealing with is not typical memory from the linear
map. The get_user_pages_fast() path, since it does not resolve the vma,
is already using {pte,pmd}_devmap() as a stand-in for VM_MIXEDMAP, so we
use that as a VM_MIXEDMAP replacement in some locations. In the cases
where there is no pte to consult we fallback to using vma_is_dax() to
detect the VM_MIXEDMAP special case.

This patch series passes a run of the ndctl unit test suite and the
'mmap.sh' [2] test in particular. 'mmap.sh' tries to catch dependencies
on VM_MIXEDMAP and {pte,pmd}_devmap().

[1]: https://lkml.org/lkml/2017/9/25/638
[2]: https://github.com/pmem/ndctl/blob/master/test/mmap.sh

---

Dan Williams (3):
      dax: disable filesystem dax on devices that do not map pages
      dax: stop using VM_MIXEDMAP for dax
      dax: stop using VM_HUGEPAGE for dax


 drivers/dax/device.c |    1 -
 drivers/dax/super.c  |    7 +++++++
 fs/ext2/file.c       |    1 -
 fs/ext4/file.c       |    1 -
 fs/xfs/xfs_file.c    |    2 --
 mm/huge_memory.c     |    8 ++++----
 mm/ksm.c             |    3 +++
 mm/madvise.c         |    2 +-
 mm/memory.c          |   20 ++++++++++++++++++--
 mm/migrate.c         |    3 ++-
 mm/mlock.c           |    3 ++-
 mm/mmap.c            |    5 +++--
 12 files changed, 40 insertions(+), 16 deletions(-)

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