[PATCH v3 0/4] hugetlb: Disable huge pmd unshare for uffd-wp

[Peter Xu <peterx@redhat.com>]

v3:
- patch 4:
  - fix build failure for !CMA and/or !HUGETLBFS [Axel]
  - Fix mmu notifier range to use start/end [Mike]
- add more r-bs

v2:
- patch 4: move hugetlb_unshare_all_pmds() into mm/hugetlb.c, so it can be used
  even outside userfaultfd.c

This series tries to disable huge pmd unshare of hugetlbfs backed memory for
uffd-wp.  Although uffd-wp of hugetlbfs is still during rfc stage, the idea of
this series may be needed for multiple tasks (Axel's uffd minor fault series,
and Mike's soft dirty series), so I picked it out from the larger series.

References works:

Uffd shmem+hugetlbfs rfc:
https://lore.kernel.org/lkml/20210115170907.24498-1-peterx@redhat.com/

Uffd minor mode for hugetlbfs:
https://lore.kernel.org/lkml/20210212215403.3457686-1-axelrasmussen@google.com/

Soft dirty for hugetlbfs:
https://lore.kernel.org/lkml/20210211000322.159437-1-mike.kravetz@oracle.com/

Please review, thanks.

Peter Xu (4):
  hugetlb: Pass vma into huge_pte_alloc() and huge_pmd_share()
  hugetlb/userfaultfd: Forbid huge pmd sharing when uffd enabled
  mm/hugetlb: Move flush_hugetlb_tlb_range() into hugetlb.h
  hugetlb/userfaultfd: Unshare all pmds for hugetlbfs when register wp

 arch/arm64/mm/hugetlbpage.c   |  7 ++-
 arch/ia64/mm/hugetlbpage.c    |  3 +-
 arch/mips/mm/hugetlbpage.c    |  4 +-
 arch/parisc/mm/hugetlbpage.c  |  2 +-
 arch/powerpc/mm/hugetlbpage.c |  3 +-
 arch/s390/mm/hugetlbpage.c    |  2 +-
 arch/sh/mm/hugetlbpage.c      |  2 +-
 arch/sparc/mm/hugetlbpage.c   |  1 +
 fs/userfaultfd.c              |  4 ++
 include/linux/hugetlb.h       | 18 ++++++-
 include/linux/userfaultfd_k.h |  9 ++++
 mm/hugetlb.c                  | 94 +++++++++++++++++++++++++++--------
 mm/userfaultfd.c              |  2 +-
 13 files changed, 116 insertions(+), 35 deletions(-)

-- 
2.26.2