[PATCH 02/11] mm: page_vma_mapped_walk(): settle PageHuge on entry

Hugh Dickins
2021-06-10T06:36:41Z

page_vma_mapped_walk() cleanup: get the hugetlbfs PageHuge case
out of the way at the start, so no need to worry about it later.

Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
---
mm/page_vma_mapped.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
index a6dbf714ca15..7c0504641fb8 100644
--- a/mm/page_vma_mapped.c
+++ b/mm/page_vma_mapped.c
@@ -153,10 +153,11 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
if (pvmw->pmd && !pvmw->pte)
return not_found(pvmw);

- if (pvmw->pte)
- goto next_pte;
-
if (unlikely(PageHuge(page))) {
+ /* The only possible mapping was handled on last iteration */
+ if (pvmw->pte)
+ return not_found(pvmw);
+
/* when pud is not present, pte will be NULL */
pvmw->pte = huge_pte_offset(mm, pvmw->address, page_size(page));
if (!pvmw->pte)
@@ -168,6 +169,9 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
return not_found(pvmw);
return true;
}
+
+ if (pvmw->pte)
+ goto next_pte;
restart:
pgd = pgd_offset(mm, pvmw->address);
if (!pgd_present(*pgd))
@@ -233,7 +237,7 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
return true;
next_pte:
/* Seek to next pte only makes sense for THP */
- if (!PageTransHuge(page) || PageHuge(page))
+ if (!PageTransHuge(page))
return not_found(pvmw);
end = vma_address_end(page, pvmw->vma);
do {
--
2.26.2