[PATCH v3 4/4] mm/hugetlb: Convert use of struct page to folio in __unmap_hugepage_range()

nifan.cxl
2025-04-28T17:18:30Z

From: Fan Ni <fan.ni@samsung.com>

In __unmap_hugepage_range(), the "page" pointer always points to the
first page of a huge page, which guarantees there is a folio associating
with it. Convert the "page" pointer to use folio.

Signed-off-by: Fan Ni <fan.ni@samsung.com>
---
mm/hugetlb.c | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 6696206d556e..293c2afa724b 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5815,12 +5815,12 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
pte_t *ptep;
pte_t pte;
spinlock_t *ptl;
- struct page *page;
struct hstate *h = hstate_vma(vma);
unsigned long sz = huge_page_size(h);
bool adjust_reservation = false;
unsigned long last_addr_mask;
bool force_flush = false;
+ const bool folio_provided = !!folio;

WARN_ON(!is_vm_hugetlb_page(vma));
BUG_ON(start & ~huge_page_mask(h));
@@ -5879,14 +5879,13 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
continue;
}

- page = pte_page(pte);
/*
* If a reference page is supplied, it is because a specific
* page is being unmapped, not a range. Ensure the page we
* are about to unmap is the actual page of interest.
*/
- if (folio) {
- if (page_folio(page) != folio) {
+ if (folio_provided) {
+ if (folio != page_folio(pte_page(pte))) {
spin_unlock(ptl);
continue;
}
@@ -5896,12 +5895,14 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
* looking like data was lost
*/
set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
+ } else {
+ folio = page_folio(pte_page(pte));
}

pte = huge_ptep_get_and_clear(mm, address, ptep, sz);
tlb_remove_huge_tlb_entry(h, tlb, ptep, address);
if (huge_pte_dirty(pte))
- set_page_dirty(page);
+ folio_mark_dirty(folio);
/* Leave a uffd-wp pte marker if needed */
if (huge_pte_uffd_wp(pte) &&
!(zap_flags & ZAP_FLAG_DROP_MARKER))
@@ -5909,7 +5910,7 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
make_pte_marker(PTE_MARKER_UFFD_WP),
sz);
hugetlb_count_sub(pages_per_huge_page(h), mm);
- hugetlb_remove_rmap(page_folio(page));
+ hugetlb_remove_rmap(folio);

/*
* Restore the reservation for anonymous page, otherwise the
@@ -5918,8 +5919,8 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
* reservation bit.
*/
if (!h->surplus_huge_pages && __vma_private_lock(vma) &&
- folio_test_anon(page_folio(page))) {
- folio_set_hugetlb_restore_reserve(page_folio(page));
+ folio_test_anon(folio)) {
+ folio_set_hugetlb_restore_reserve(folio);
/* Reservation to be adjusted after the spin lock */
adjust_reservation = true;
}
@@ -5943,16 +5944,17 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
* count will not be incremented by free_huge_folio.
* Act as if we consumed the reservation.
*/
- folio_clear_hugetlb_restore_reserve(page_folio(page));
+ folio_clear_hugetlb_restore_reserve(folio);
else if (rc)
vma_add_reservation(h, vma, address);
}

- tlb_remove_page_size(tlb, page, huge_page_size(h));
+ tlb_remove_page_size(tlb, folio_page(folio, 0),
+ folio_size(folio));
/*
* Bail out after unmapping reference page if supplied
*/
- if (folio)
+ if (folio_provided)
break;
}
tlb_end_vma(tlb, vma);
--
2.47.2