[merged mm-stable] mm-hugetlb_vmemmap-fix-__hugetlb_vmemmap_optimize_folios.patch removed from -mm tree

The quilt patch titled
     Subject: mm/hugetlb_vmemmap: fix __hugetlb_vmemmap_optimize_folios()
has been removed from the -mm tree.  Its filename was
     mm-hugetlb_vmemmap-fix-__hugetlb_vmemmap_optimize_folios.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Muchun Song <[email protected]>
Subject: mm/hugetlb_vmemmap: fix __hugetlb_vmemmap_optimize_folios()
Date: Fri, 12 Jun 2026 11:58:46 +0800

__hugetlb_vmemmap_optimize_folios() uses incorrect arguments when handling
bootmem HugeTLB folios.

The section number passed to register_page_bootmem_memmap() is derived
from the vmemmap virtual address of folio->page instead of the folio PFN,
so the bootmem memmap metadata can be registered against the wrong
section.  The helper is also given HUGETLB_VMEMMAP_RESERVE_SIZE even
though it expects a page count, not a size in bytes.  In addition, the
write-protect range is based on pages_per_huge_page(h), which does not
cover the full HugeTLB vmemmap area and can leave part of the shared tail
vmemmap mapping writable.

Fix the section lookup to use folio_pfn(folio), use
HUGETLB_VMEMMAP_RESERVE_PAGES when registering the reserved memmap pages,
and use hugetlb_vmemmap_size(h) for the write-protect range.

Link: https://lore.kernel.org/[email protected]
Fixes: 752fe17af693 ("mm/hugetlb: add pre-HVO framework")
Signed-off-by: Muchun Song <[email protected]>
Acked-by: Oscar Salvador <[email protected]>
Reviewed-by: Frank van der Linden <[email protected]>
Cc: "Aneesh Kumar K.V" <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Liam R. Howlett <[email protected]>
Cc: Lorenzo Stoakes <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Mike Rapoport (Microsoft) <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Oscar Salvador (SUSE) <[email protected]>
Cc: "Ritesh Harjani (IBM)" <[email protected]>
Cc: Usama Arif <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---

 mm/hugetlb_vmemmap.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/mm/hugetlb_vmemmap.c~mm-hugetlb_vmemmap-fix-__hugetlb_vmemmap_optimize_folios
+++ a/mm/hugetlb_vmemmap.c
@@ -635,12 +635,12 @@ static void __hugetlb_vmemmap_optimize_f
 			 * mirrored tail page structs RO.
 			 */
 			spfn = (unsigned long)&folio->page;
-			epfn = spfn + pages_per_huge_page(h);
+			epfn = spfn + hugetlb_vmemmap_size(h);
 			vmemmap_wrprotect_hvo(spfn, epfn, folio_nid(folio),
 					HUGETLB_VMEMMAP_RESERVE_SIZE);
-			register_page_bootmem_memmap(pfn_to_section_nr(spfn),
+			register_page_bootmem_memmap(pfn_to_section_nr(folio_pfn(folio)),
 					&folio->page,
-					HUGETLB_VMEMMAP_RESERVE_SIZE);
+					HUGETLB_VMEMMAP_RESERVE_PAGES);
 			continue;
 		}
 
_

Patches currently in -mm which might be from [email protected] are

selftests-mm-remove-obsolete-hugetlb-vmemmap-test.patch