[PATCH v2 05/19] mm/gup: Detect huge pfnmap entries in gup-fast

[Peter Xu <peterx@redhat.com>]

Since gup-fast doesn't have the vma reference, teach it to detect such huge
pfnmaps by checking the special bit for pmd/pud too, just like ptes.

Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
 mm/gup.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/mm/gup.c b/mm/gup.c
index d19884e097fd..a49f67a512ee 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -3038,6 +3038,9 @@ static int gup_fast_pmd_leaf(pmd_t orig, pmd_t *pmdp, unsigned long addr,
 	if (!pmd_access_permitted(orig, flags & FOLL_WRITE))
 		return 0;
 
+	if (pmd_special(orig))
+		return 0;
+
 	if (pmd_devmap(orig)) {
 		if (unlikely(flags & FOLL_LONGTERM))
 			return 0;
@@ -3082,6 +3085,9 @@ static int gup_fast_pud_leaf(pud_t orig, pud_t *pudp, unsigned long addr,
 	if (!pud_access_permitted(orig, flags & FOLL_WRITE))
 		return 0;
 
+	if (pud_special(orig))
+		return 0;
+
 	if (pud_devmap(orig)) {
 		if (unlikely(flags & FOLL_LONGTERM))
 			return 0;
-- 
2.45.0