[PATCH RFC v2 09/12] mm/hugetlb: Use hugetlb walker lock in hugetlb_vma_maps_page()

Peter Xu
2022-11-18T01:13:09Z

Hugetlb walker lock makes sure the pte_t* won't go away from under us.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
fs/hugetlbfs/inode.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index fdb16246f46e..265508981ba1 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -387,21 +387,24 @@ static bool hugetlb_vma_maps_page(struct vm_area_struct *vma,
unsigned long addr, struct page *page)
{
pte_t *ptep, pte;
+ bool result = false;

+ hugetlb_walker_lock();
ptep = huge_pte_offset(vma->vm_mm, addr,
huge_page_size(hstate_vma(vma)));

if (!ptep)
- return false;
+ goto out;

pte = huge_ptep_get(ptep);
if (huge_pte_none(pte) || !pte_present(pte))
- return false;
+ goto out;

if (pte_page(pte) == page)
- return true;
-
- return false;
+ result = true;
+out:
+ hugetlb_walker_unlock();
+ return result;
}

/*
--
2.37.3