+ mm-huge_memory-remove-vma_is_special_huge.patch added to mm-unstable branch

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

The patch titled
     Subject: mm/huge_memory: remove vma_is_special_huge()
has been added to the -mm mm-unstable branch.  Its filename is
     mm-huge_memory-remove-vma_is_special_huge.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-remove-vma_is_special_huge.patch

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

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------------------------------------------------------
From: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
Subject: mm/huge_memory: remove vma_is_special_huge()
Date: Fri, 09 Oct 2026 19:04:32 +0100

vma_is_special_huge() tests whether either the VMA_PFNMAP_BIT or
VMA_MIXEDMAP_BIT is set (i.e. whether the VMA is not mm-managed),
but with a DAX carve-out.

DAX however no longer sets VMA_MIXEDMAP_BIT, so this carve-out is no longer
required.

Therefore test for !vma_is_mm_managed() instead and also drop the
VMA_IO_BIT check, as it is now redundant since it is enforced that
mm-managed mappings may not set VMA_IO_BIT.

This also eliminates another overloaded use of 'special' within mm.

No functional change intended.

Link: https://lore.kernel.org/20261009-b4-mmap-prepare-vma-flag-sanify-v5-38-923b70125b1e@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Zi Yan <ziy@nvidia.com>
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---

 mm/huge_memory.c |   18 ++++--------------
 1 file changed, 4 insertions(+), 14 deletions(-)

--- a/mm/huge_memory.c~mm-huge_memory-remove-vma_is_special_huge
+++ a/mm/huge_memory.c
@@ -110,14 +110,6 @@ static inline bool file_thp_enabled(cons
 	return S_ISREG(inode->i_mode);
 }
 
-/* If returns true, we are unable to access the VMA's folios. */
-static bool vma_is_special_huge(const struct vm_area_struct *vma)
-{
-	if (vma_is_dax(vma))
-		return false;
-	return vma_test_any(vma, VMA_PFNMAP_BIT, VMA_MIXEDMAP_BIT);
-}
-
 static bool vma_file_bypass_thp_tuneables(const struct vm_area_struct *vma,
 		enum tva_type type)
 {
@@ -192,7 +184,7 @@ unsigned long __thp_vma_allowable_orders
 	/* Check the intersection of requested and supported orders. */
 	if (vma_is_anonymous(vma))
 		supported_orders = THP_ORDERS_ALL_ANON;
-	else if (vma_is_dax(vma) || vma_is_special_huge(vma))
+	else if (vma_is_dax(vma) || !vma_is_mm_managed(vma))
 		supported_orders = THP_ORDERS_ALL_SPECIAL_DAX;
 	else
 		supported_orders = THP_ORDERS_ALL_FILE_DEFAULT;
@@ -3056,7 +3048,7 @@ int zap_huge_pud(struct mmu_gather *tlb,
 	orig_pud = pudp_huge_get_and_clear_full(vma, addr, pud, tlb->fullmm);
 	arch_check_zapped_pud(vma, orig_pud);
 	tlb_remove_pud_tlb_entry(tlb, pud, addr);
-	if (vma_is_special_huge(vma)) {
+	if (!vma_is_mm_managed(vma)) {
 		spin_unlock(ptl);
 		/* No zero page support yet */
 	} else {
@@ -3212,7 +3204,7 @@ static void __split_huge_pmd_locked(stru
 		 */
 		if (arch_needs_pgtable_deposit())
 			zap_deposited_table(mm, pmd);
-		if (vma_is_special_huge(vma))
+		if (!vma_is_mm_managed(vma))
 			return;
 		if (unlikely(pmd_is_migration_entry(old_pmd))) {
 			const softleaf_t old_entry = softleaf_from_pmd(old_pmd);
@@ -4779,9 +4771,7 @@ static inline bool vma_not_suitable_for_
 {
 	if (vma_is_dax(vma))
 		return true;
-	if (vma_is_special_huge(vma))
-		return true;
-	if (vma_test(vma, VMA_IO_BIT))
+	if (!vma_is_mm_managed(vma))
 		return true;
 	if (vma_is_hugetlb(vma))
 		return true;
_

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

mm-vma-fix-mmap_prepare-file-handling-remove-file_doesnt_need_get.patch
mm-vma-introduce-and-use-vma_can_merge.patch
mm-consistently-validate-vma-state-after-mmap-hooks.patch
mm-vma-ensure-mmap_prepare-doesnt-set-actions-on-a-mergeable-vma.patch
mm-make-map_kernel_pages_-internal-and-unexported.patch
mm-vma-tidy-up-map-kernel-pages-enum-values.patch
mm-add-mmap-action-for-discontiguous-kernel-page-mapping.patch
docs-filesystems-update-mmap_prepare-docs-for-discontig-kernel-pgs.patch
drivers-usb-mon-update-to-use-mmap_prepare-map-kernel-pages.patch
infiniband-update-hfi1-to-use-remap_vmalloc_range.patch
selinux-reject-writable-opens-of-policy-file-drop-mmap-shared-write-check.patch
alsa-pcm-use-vm_insert_page-to-map-pcm-status-page.patch
bpf-arena-mark-arena_map_mmap-mappings-vm_mixedmap.patch
mm-vma-add-vma_is_mm_managed-predicates.patch
mm-vma-only-allow-mmap-to-clear-vma_maywrite_bit-if-not-mm-managed.patch
mm-vma-add-and-use-vma__is_fixed_mapping.patch
scsi-sg-convert-mmap-hook-to-mmap_prepare-and-rework.patch
fbdev-defio-assert-fbinfo_virtfb-drop-vm_io-add-vm_mixedmap.patch
hsi-cmt_speech-convert-mmap-hook-to-mmap_prepare-refactor.patch
mm-gup-error-out-early-on-vma_mayread_bit-vmas.patch
uprobes-remove-vm_io-set-vm_mixedmap-for-mapped-kernel-pages.patch
mm-mlock-clear-vma_locked_mask-over-mmap-callback.patch
mm-mlock-eliminate-weird-vma_io_bit-abuse-and-simplify.patch
mm-vma-enforce-that-mm-managed-mappings-may-not-set-vma_io_bit.patch
mm-remove-vma_io_bit-check-in-vma_is_mm_managed.patch
mm-remove-hugetlb_inlineh.patch
mm-rename-is_vm_hugetlb_page-to-vma_is_hugetlb.patch
mm-drop-some-redundant-checks-around-hugetlb-vmas.patch
mm-madvise-update-is_valid_guard_vma-to-use-vma_can_merge.patch
mm-vma-introduce-vma_is_mm_backed.patch
mm-uffd-use-predicates-for-userfaultfd-checks.patch
mm-madvise-use-predicates-for-madvise-madv_dofork.patch
mm-eliminate-vma_special_flags-usage-when-hugetlb-explicitly-tested.patch
mm-eliminate-vma_special_flags-check-in-lru_gen_look_around.patch
mm-avoid-use-of-vma_special_flags-in-migrate_vma_setup.patch
mm-eliminate-vm_special-vma_special_flags.patch
fuse-dax-do-not-set-vm_mixedmap.patch
mm-huge_memory-remove-vma_is_special_huge.patch
mm-vma-const-ify-vma_assert_stabilised-and-associated-functions.patch
mm-implement-and-use-vma_has_anon_rmap-silence-kcsan.patch
mm-update-comments-to-refer-to-anon-rmap-rather-than-anon_vma.patch
mm-vma-dont-remove-vma-from-rmap-if-pgoff-unchanged.patch