[RFC 3/9] mm/gup: Make follow_page_mask function PGD implementation aware

[Anshuman Khandual]

Currently the function 'follow_page_mask' does not take into account
PGD based huge page implementation. This change achieves that and
makes it complete.

Signed-off-by: Anshuman Khandual <khandual at linux.vnet.ibm.com>
---
 mm/gup.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/mm/gup.c b/mm/gup.c
index 7bf19ff..53a2013 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -232,6 +232,12 @@ struct page *follow_page_mask(struct vm_area_struct *vma,
 	pgd = pgd_offset(mm, address);
 	if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
 		return no_page_table(vma, flags);
+	if (pgd_huge(*pgd) && vma->vm_flags & VM_HUGETLB) {
+		page = follow_huge_pgd(mm, address, pgd, flags);
+		if (page)
+			return page;
+		return no_page_table(vma, flags);
+	}
 
 	pud = pud_offset(pgd, address);
 	if (pud_none(*pud))
-- 
2.1.0