mm/hugetlb: alloc_huge_page handle areas hole punched by fallocate

mm/hugetlb: alloc_huge_page handle areas hole punched by fallocate

Areas hole punched by fallocate will not have entries in the
region/reserve map.  However, shared mappings with min_size subpool
reservations may still have reserved pages.  alloc_huge_page needs to
handle this special case and do the proper accounting.

Signed-off-by: Mike Kravetz <[email protected]>
Reviewed-by: Naoya Horiguchi <[email protected]>
Acked-by: Hillf Danton <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: Aneesh Kumar <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Michal Hocko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>