mm/gup: fix gup_pmd_range() for dax

For dax pmd, pmd_trans_huge() returns false but pmd_huge() returns true
on x86.  So the function works as long as hugetlb is configured.
However, dax doesn't depend on hugetlb.

Link: http://lkml.kernel.org/r/20190111034033.601-1-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Keith Busch <keith.busch@intel.com>
Cc: "Michael S . Tsirkin" <mst@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/gup.c b/mm/gup.c
index 05acd7e2eb22e0849c5125d0cabc671fdc58f71f..75029649baca4ac834732b931cb9f743cdc58afb 100644 (file)
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1674,7 +1674,8 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end,
                if (!pmd_present(pmd))
                        return 0;
 
-               if (unlikely(pmd_trans_huge(pmd) || pmd_huge(pmd))) {
+               if (unlikely(pmd_trans_huge(pmd) || pmd_huge(pmd) ||
+                            pmd_devmap(pmd))) {
                        /*
                         * NUMA hinting faults need to be handled in the GUP
                         * slowpath for accounting purposes and so that they