[PATCH v2 0/2] A couple hugetlbfs fixes

[Mike Kravetz <mike.kravetz@oracle.com>]

I stumbled on these two hugetlbfs issues while looking at other things:
- The 'restore reserve' functionality at page free time should not
  be adjusting subpool counts.
- A BUG can be triggered (not easily) due to temporarily mapping a
  page before doing a COW.

Both are described in detail in the commit message of the patches.
I would appreciate comments from Davidlohr Bueso as one patch is
directly related to code he added in commit 8382d914ebf7.

I did not cc stable as the first problem has been around since reserves
were added to hugetlbfs and nobody has noticed.  The second is very hard
to hit/reproduce.

v2 - Update definition and all callers of hugetlb_fault_mutex_hash as
     the arguments mm and vma are no longer used or necessary.

Mike Kravetz (2):
  huegtlbfs: on restore reserve error path retain subpool reservation
  hugetlb: use same fault hash key for shared and private mappings

 fs/hugetlbfs/inode.c    |  7 ++-----
 include/linux/hugetlb.h |  4 +---
 mm/hugetlb.c            | 43 +++++++++++++++++++++--------------------
 mm/userfaultfd.c        |  3 +--
 4 files changed, 26 insertions(+), 31 deletions(-)

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2.20.1