+ mm-huge_memory-simplify-pgtable-deposit-detection.patch added to mm-hotfixes-unstable branch

+ mm-huge_memory-simplify-pgtable-deposit-detection.patch added to mm-hotfixes-unstable branch

[Andrew Morton]

The patch titled
     Subject: mm/huge_memory: simplify pgtable deposit detection
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     mm-huge_memory-simplify-pgtable-deposit-detection.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-huge_memory-simplify-pgtable-deposit-detection.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Lance Yang <lance.yang@linux.dev>
Subject: mm/huge_memory: simplify pgtable deposit detection
Date: Thu, 17 Sep 2026 13:40:15 +0800

Whether a PMD has a deposited PTE page table only depends on whether the
architecture requires deposits or the VMA is anonymous.

Implement this rule directly in vma_has_deposited_pgtable(), avoiding
mistaking a non-anonymous raw PFN PMD for one with a deposit and
attempting to withdraw a page table that was never deposited.

Link: https://lore.kernel.org/20260917054015.23553-1-lance.yang@linux.dev
Signed-off-by: Lance Yang <lance.yang@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Suggested-by: David Hildenbrand <david@kernel.org>
Reviewed-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Zi Yan <ziy@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
---

 mm/huge_memory.c |   22 +++++-----------------
 1 file changed, 5 insertions(+), 17 deletions(-)

--- a/mm/huge_memory.c~mm-huge_memory-simplify-pgtable-deposit-detection
+++ a/mm/huge_memory.c
@@ -2514,25 +2514,13 @@ static struct folio *normal_or_softleaf_
 	return pmd_to_softleaf_folio(pmdval);
 }
 
-static bool has_deposited_pgtable(struct vm_area_struct *vma, pmd_t pmdval,
-		struct folio *folio)
+static bool vma_has_deposited_pgtable(struct vm_area_struct *vma)
 {
-	/* Some architectures require unconditional depositing. */
-	if (arch_needs_pgtable_deposit())
-		return true;
-
-	/*
-	 * Huge zero always deposited except for DAX which handles itself, see
-	 * set_huge_zero_folio().
-	 */
-	if (is_huge_zero_pmd(pmdval))
-		return !vma_is_dax(vma);
-
 	/*
-	 * Otherwise, only anonymous folios are deposited, see
-	 * __do_huge_pmd_anonymous_page().
+	 * PMDs in anonymous VMAs always have a deposited page table. PMDs in
+	 * other VMAs only have one when required by the architecture.
 	 */
-	return folio && folio_test_anon(folio);
+	return arch_needs_pgtable_deposit() || vma_is_anonymous(vma);
 }
 
 /**
@@ -2572,7 +2560,7 @@ bool zap_huge_pmd(struct mmu_gather *tlb
 
 	is_present = pmd_present(orig_pmd);
 	folio = normal_or_softleaf_folio_pmd(vma, addr, orig_pmd, is_present);
-	has_deposit = has_deposited_pgtable(vma, orig_pmd, folio);
+	has_deposit = vma_has_deposited_pgtable(vma);
 	if (folio)
 		zap_huge_pmd_folio(mm, vma, orig_pmd, folio, is_present);
 	if (has_deposit)
_

Patches currently in -mm which might be from lance.yang@linux.dev are

mm-huge_memory-simplify-pgtable-deposit-detection.patch
mm-huge_memory-fix-pgtable-withdrawal-for-huge-zero-pmds.patch