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

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

[Andrew Morton]

The patch titled
     Subject: mm/huge_memory: remove vma_is_special_huge()
has been added to the -mm mm-new 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-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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------------------------------------------------------
From: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
Subject: mm/huge_memory: remove vma_is_special_huge()
Date: Mon, 14 Sep 2026 15:57:59 +0100

vma_is_special_huge() tests whether either the VMA_PFNMAP_BIT or
VMA_MIXEDMAP_BIT is set (i.e.  whether the VMA is a kernel-owned mapping),
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_kernel_owned() instead and also drop the
VMA_IO_BIT check, as it is now redundant since it is enforced that only
kernel-owned mappings can set this flag.

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

No functional change intended.

Link: https://lore.kernel.org/20260914-b4-mmap-prepare-vma-flag-sanify-v2-39-7d9781ed5361@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 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_kernel_owned(vma))
 		supported_orders = THP_ORDERS_ALL_SPECIAL_DAX;
 	else
 		supported_orders = THP_ORDERS_ALL_FILE_DEFAULT;
@@ -3066,7 +3058,7 @@ 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_kernel_owned(vma)) {
 		spin_unlock(ptl);
 		/* No zero page support yet */
 	} else {
@@ -3222,7 +3214,7 @@ 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_kernel_owned(vma))
 			return;
 		if (unlikely(pmd_is_migration_entry(old_pmd))) {
 			const softleaf_t old_entry = softleaf_from_pmd(old_pmd);
@@ -4790,9 +4782,7 @@ 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_kernel_owned(vma))
 		return true;
 	if (vma_is_hugetlb(vma))
 		return true;
_

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

mm-vmpressure-remove-window-size-todo.patch
tools-testing-selftests-mm-add-missing-gitignore-entries.patch
mm-move-drivers-char-memc-to-mm-char-memc.patch
mm-implement-file_is_dev_zero-to-uniquely-identify-dev-zero.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-madvise-swap-in-cowd-map_private-file-mappings-on-madv_willneed.patch
mm-huge_memory-zap-deposited-page-tables-after-an-rcu-grace-period.patch
mm-enable-mmu_gather_rcu_table_free-for-most-2-level-architectures.patch
mm-enable-mmu_gather_rcu_table_free-for-mmu-riscv.patch
mm-enable-mmu_gather_rcu_table_free-for-mmu-arm.patch
mm-enable-mmu_gather_rcu_table_free-for-arc-microblaze-xtensa.patch
mm-enable-mmu_gather_rcu_table_free-for-sparc64.patch
mm-enable-mmu_gather_rcu_table_free-for-m68k-coldfire.patch
mm-enable-mmu_gather_rcu_table_free-for-sh-x2.patch
mm-enable-mmu_gather_rcu_table_free-for-m68k-motorola.patch
mm-enable-mmu_gather_rcu_table_free-for-sparc32.patch
mm-make-userland-page-table-freeing-rcu-safe.patch
mm-change-the-contract-for-free_pgtables-update-docs.patch
mm-vma-fix-mmap_prepare-file-handling-remove-file_doesnt_need_get.patch
mm-vma-predicate-setting-mmap_prepare-vma-fields-on-new-vma-alloc.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_kernel_owned-predicates.patch
mm-vma-only-allow-mmap-to-clear-vma_maywrite_bit-if-kernel-owned.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-only-kernel-owned-mappings-may-set-vma_io_bit.patch
mm-remove-vma_io_bit-check-in-vma_is_kernel_owned.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_persistent.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-introduce-and-use-vma_can_gup.patch