[PATCH] mm/gup: fix gup_pud_range() for dax

From: Saurabh Sengar
Date: Thu Oct 20 2022 - 14:14:59 EST


From: John Starks <jostarks@xxxxxxxxxxxxx>

For dax pud, pud_huge() returns true on x86. So the function works as long
as hugetlb is configured. However, dax doesn't depend on hugetlb.
Commit 414fd080d125 ("mm/gup: fix gup_pmd_range() for dax") fixed
devmap-backed huge PMDs, but missed devmap-backed huge PUDs. Fix this as
well.

Fixes: 414fd080d125 ("mm/gup: fix gup_pmd_range() for dax")
Signed-off-by: John Starks <jostarks@xxxxxxxxxxxxx>
Signed-off-by: Saurabh Sengar <ssengar@xxxxxxxxxxxxxxxxxxx>
---
mm/gup.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/gup.c b/mm/gup.c
index 05068d3d2557..9e07aa54a4cd 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2687,7 +2687,7 @@ static int gup_pud_range(p4d_t *p4dp, p4d_t p4d, unsigned long addr, unsigned lo
next = pud_addr_end(addr, end);
if (unlikely(!pud_present(pud)))
return 0;
- if (unlikely(pud_huge(pud))) {
+ if (unlikely(pud_huge(pud) || pud_devmap(pud))) {
if (!gup_huge_pud(pud, pudp, addr, next, flags,
pages, nr))
return 0;
--
2.25.1