mm/gup: check for protnone only if it is a PTE entry

Do the prot_none/FOLL_NUMA check after we are sure this is a THP pte.
Archs can implement prot_none such that it can return true for regular
pmd entries.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Aneesh Kumar K.V <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Hillf Danton <[email protected]>
Cc: Kirill A. Shutemov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/mm/gup.c b/mm/gup.c
index 1e67461b2733095a90a39e5c21c75e76651c728e..94fab8fa432b2f46ccb0c0238a17cb750489896e 100644 (file)
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -272,8 +272,6 @@ struct page *follow_page_mask(struct vm_area_struct *vma,
                        return page;
                return no_page_table(vma, flags);
        }
-       if ((flags & FOLL_NUMA) && pmd_protnone(*pmd))
-               return no_page_table(vma, flags);
        if (pmd_devmap(*pmd)) {
                ptl = pmd_lock(mm, pmd);
                page = follow_devmap_pmd(vma, address, pmd, flags);
@@ -284,6 +282,9 @@ struct page *follow_page_mask(struct vm_area_struct *vma,
        if (likely(!pmd_trans_huge(*pmd)))
                return follow_page_pte(vma, address, pmd, flags);
 
+       if ((flags & FOLL_NUMA) && pmd_protnone(*pmd))
+               return no_page_table(vma, flags);
+
        ptl = pmd_lock(mm, pmd);
        if (unlikely(!pmd_trans_huge(*pmd))) {
                spin_unlock(ptl);