[PATCH] mm/gup: Check for protnone only if it is a PTE entry.

From: Aneesh Kumar K.V
Date: Sun Feb 19 2017 - 04:59:32 EST


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.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
---
mm/gup.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/mm/gup.c b/mm/gup.c
index 55315555489d..bb5f3d69f87e 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -265,8 +265,6 @@ 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);
@@ -277,6 +275,9 @@ 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);
--
2.7.4