Here is a modification to the reservation tracking for fixup on errors.
It is a more general change, but should work for the hugetlb_mcopy_pte_atomic
case as well.

Perhaps use this as a prerequisite for your fix(es)?  Pretty sure this
will eliminate the need for the call to hugetlb_unreserve_pages.

Mike Kravetz (2):
  hugetlb: rename HPageRestoreReserve flag to HPageRestoreRsvCnt
  hugetlb: add new hugetlb specific flag HPG_restore_rsv_map

 fs/hugetlbfs/inode.c    |   3 +-
 include/linux/hugetlb.h |  17 +++++--
 mm/hugetlb.c            | 108 ++++++++++++++++++++++++++++------------
 mm/userfaultfd.c        |  14 +++---
 4 files changed, 99 insertions(+), 43 deletions(-)

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2.31.1