[merged mm-stable] mm-vma-clean-up-anon_vma_compatible.patch removed from -mm tree

[Andrew Morton <akpm@linux-foundation.org>]

The quilt patch titled
     Subject: mm/vma: clean up anon_vma_compatible()
has been removed from the -mm tree.  Its filename was
     mm-vma-clean-up-anon_vma_compatible.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: Lorenzo Stoakes <ljs@kernel.org>
Subject: mm/vma: clean up anon_vma_compatible()
Date: Fri, 10 Jul 2026 21:16:55 +0100

Break up the existing very large conditional, add comments and use
vma_[start/end]_pgoff() to make clearer what we're doing here.

No functional change intended.

Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-14-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/vma.c |   21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

--- a/mm/vma.c~mm-vma-clean-up-anon_vma_compatible
+++ a/mm/vma.c
@@ -1967,14 +1967,25 @@ static int anon_vma_compatible(struct vm
 {
 	vma_flags_t diff = vma_flags_diff_pair(&a->flags, &b->flags);
 
+	/* Ignore flags that mprotect() can change. */
 	vma_flags_clear_mask(&diff, VMA_ACCESS_FLAGS);
+	/* Ignore flags that do not impact merging. */
 	vma_flags_clear_mask(&diff, VMA_IGNORE_MERGE_FLAGS);
 
-	return a->vm_end == b->vm_start &&
-		mpol_equal(vma_policy(a), vma_policy(b)) &&
-		a->vm_file == b->vm_file &&
-		vma_flags_empty(&diff) &&
-		b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT);
+	/* Must be adjacent. */
+	if (a->vm_end != b->vm_start)
+		return false;
+	/* Must have matching policy. */
+	if (!mpol_equal(vma_policy(a), vma_policy(b)))
+		return false;
+	/* Must both be anon or map the same file (MAP_PRIVATE case). */
+	if (a->vm_file != b->vm_file)
+		return false;
+	/* Flags must be equivalent modulo mprotect(). */
+	if (!vma_flags_empty(&diff))
+		return false;
+	/* Page offset must align. */
+	return vma_end_pgoff(a) == vma_start_pgoff(b);
 }
 
 /*
_

Patches currently in -mm which might be from ljs@kernel.org are

mm-vmalloc-acquire-init_mm-lock-on-huge-vmap-to-avoid-ptdump-uaf.patch
mm-ptdump-always-stabilise-against-page-table-freeing-using-init_mm.patch
arm64-remove-redundant-concurrent-ptdump-uaf-mitigation.patch
mm-huge_memory-fix-huge_zero_pfn-race.patch
mm-huge_memory-separate-out-config_persistent_huge_zero_folio-logic.patch
x86-mm-pat-acquire-init_mm-write-lock-on-collapse-to-avoid-uaf.patch
x86-mm-pat-acquire-init_mm-read-lock-on-attribute-change-to-avoid-uaf.patch
x86-mm-pat-allocate-split-page-tables-as-kernel-page-tables.patch
mm-introduce-vma_flags_can_grow-and-vma_can_grow.patch
mm-vma-update-do_mmap-to-use-vma_flags_t.patch
mm-convert-__get_unmapped_area-to-use-vma_flags_t.patch
mm-update-generic_get_unmapped_area-to-use-vma_flags_t.patch
mm-prefer-mm-def_vma_flags-in-mm-logic.patch
mm-vma-convert-vm_pgprot_modify-to-use-vma_flags_t-and-rename.patch
mm-vma-rename-vma_get_page_prot-to-vma_flags_to_page_prot.patch
mm-introduce-vma_get_page_prot-and-use-it.patch
mm-vma-update-create_init_stack_vma-to-use-vma_flags_t.patch
mm-vma-convert-miscellaneous-uses-of-vma-flags-in-core-mm.patch
mm-mlock-convert-mlock-code-to-use-vma_flags_t.patch
mm-mprotect-convert-mprotect-code-to-use-vma_flags_t.patch
mm-mremap-convert-mremap-code-to-use-vma_flags_t.patch
mm-mseal-remove-superfluous-comments-fix-confusion-around-mm.patch
mm-mseal-limit-scope-of-mseal-address-zero-to-address-zero.patch
mm-mseal-remove-further-superfluous-comments-do_mseal.patch
mm-vma-introduce-vma-virtual-page-offset-field-and-add-helpers.patch
mm-introduce-linear_virt_page_index.patch
mm-abstract-vma_address-and-introduce-vma_anon_address.patch
mm-update-print_bad_page_map-to-show-virtual-page-index.patch
mm-introduce-and-use-vma_filebacked_address.patch
mm-propagate-vma-virtual-page-offset-on-map-remap-split-merge.patch
mm-rmap-track-whether-the-page-vma-mapped-walk-is-anonymous.patch
mm-introduce-and-use-linear_folio_page_index.patch
mm-rmap-use-virt-pgoff-for-map_private-file-backed-anon-folios.patch
tools-testing-vma-expand-vma-merge-tests-to-assert-virt-pgoff.patch
tools-testing-selftests-mm-test-virtual-page-offset-merge-behaviour.patch
mm-vma-only-permit-map_private-dev-zero-to-be-mapped-anonymous.patch
mm-vma-make-map_private-mapped-dev-zero-mappings-truly-anonymous.patch
tools-testing-vma-add-test-to-assert-map_private-dev-zero-is-anon.patch
tools-testing-selftests-mm-add-map_private-dev-zero-merge-tests.patch
mm-add-some-missing-includes-to-mm-local-headers.patch