A rare out of memory error would prevent removal of the reserve map region
for a page.  hugetlb_fix_reserve_counts() handles this rare case to avoid
dangling with incorrect counts.  Unfortunately, hugepage_subpool_get_pages
and hugetlb_acct_memory could possibly fail too.  We should correctly
handle these cases.

Link: https://lkml.kernel.org/r/20210410072348.20437-5-linmiaohe@huawei.com
Fixes: b5cec28d ("hugetlbfs: truncate_hugepages() takes a range of pages")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Feilong Lin <linfeilong@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>