[PATCH 07/13] mm/madvise: convert madvise_vma_behavior() to use vma_flags_t

From: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Date: 2026-11-05 21:33:42
Also in: damon, kvm, linux-fsdevel, linux-integrity, linux-mm, linux-perf-users, linux-security-module, linuxppc-dev, lkml, selinux
Reply to: Lorenzo Stoakes (ARM), 2026-11-05

Replace use of the legacy vm_flags_t flags with vma_flags_t values
throughout the madvise logic.

In order to do so, update ksm_madvise() and hugepage_madvise() to take a
vma_flags_t pointer, and update their other callers in mremap and the
powerpc KVM ultravisor code accordingly.

In the latter case we replace vm_flags_reset() with vma_overwrite_flags().
The VMA is write locked at this point, so the atomic flags preserved by
vma_overwrite_flags() cannot differ from those copied, and the behaviour
is unchanged.

No functional change intended.

Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
---
 arch/powerpc/kvm/book3s_hv_uvmem.c | 10 ++++----
 include/linux/huge_mm.h            |  4 ++--
 include/linux/ksm.h                |  4 ++--
 mm/khugepaged.c                    | 10 ++++----
 mm/ksm.c                           | 11 +++++----
 mm/madvise.c                       | 47 ++++++++++++++++++++------------------
 mm/mremap.c                        |  2 +-
 7 files changed, 46 insertions(+), 42 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c
index 463aef870c4e..0fa50bee2ffc 100644
--- a/arch/powerpc/kvm/book3s_hv_uvmem.c
+++ b/arch/powerpc/kvm/book3s_hv_uvmem.c

@@ -393,7 +393,7 @@ static int kvmppc_memslot_page_merge(struct kvm *kvm,
 {
 	unsigned long gfn = memslot->base_gfn;
 	unsigned long end, start = gfn_to_hva(kvm, gfn);
-	vm_flags_t vm_flags;
+	vma_flags_t vma_flags;
 	int ret = 0;
 	struct vm_area_struct *vma;
 	int merge_flag = (merge) ? MADV_MERGEABLE : MADV_UNMERGEABLE;

@@ -411,15 +411,15 @@ static int kvmppc_memslot_page_merge(struct kvm *kvm,
 			break;
 		}
 		vma_start_write(vma);
-		/* Copy vm_flags to avoid partial modifications in ksm_madvise */
-		vm_flags = vma->vm_flags;
+		/* Copy flags to avoid partial modifications in ksm_madvise */
+		vma_flags = vma->flags;
 		ret = ksm_madvise(vma, vma->vm_start, vma->vm_end,
-			  merge_flag, &vm_flags);
+			  merge_flag, &vma_flags);
 		if (ret) {
 			ret = H_STATE;
 			break;
 		}
-		vm_flags_reset(vma, vm_flags);
+		vma_overwrite_flags(vma, vma_flags);
 		start = vma->vm_end;
 	} while (end > vma->vm_end);

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index c745f7ad2298..8b6f4101eabf 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h

@@ -508,7 +508,7 @@ change_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma,
 			__split_huge_pud(__vma, __pud, __address);	\
 	}  while (0)
 
-int hugepage_madvise(struct vm_area_struct *vma, vm_flags_t *vm_flags,
+int hugepage_madvise(struct vm_area_struct *vma, vma_flags_t *vma_flags,
 		     int advice);
 int madvise_collapse(struct vm_area_struct *vma, unsigned long start,
 		     unsigned long end, bool *lock_dropped);

@@ -710,7 +710,7 @@ static inline bool unmap_huge_pmd_locked(struct vm_area_struct *vma,
 	do { } while (0)
 
 static inline int hugepage_madvise(struct vm_area_struct *vma,
-				   vm_flags_t *vm_flags, int advice)
+				   vma_flags_t *vma_flags, int advice)
 {
 	return -EINVAL;
 }

diff --git a/include/linux/ksm.h b/include/linux/ksm.h
index d39d0d5483a2..1ffc69a72a1a 100644
--- a/include/linux/ksm.h
+++ b/include/linux/ksm.h

@@ -16,7 +16,7 @@
 
 #ifdef CONFIG_KSM
 int ksm_madvise(struct vm_area_struct *vma, unsigned long start,
-		unsigned long end, int advice, vm_flags_t *vm_flags);
+		unsigned long end, int advice, vma_flags_t *vma_flags);
 vma_flags_t ksm_vma_flags(struct mm_struct *mm, const struct file *file,
 			  vma_flags_t vma_flags);
 int ksm_enable_merge_any(struct mm_struct *mm);

@@ -139,7 +139,7 @@ static inline void collect_procs_ksm(const struct folio *folio,
 
 #ifdef CONFIG_MMU
 static inline int ksm_madvise(struct vm_area_struct *vma, unsigned long start,
-		unsigned long end, int advice, vm_flags_t *vm_flags)
+		unsigned long end, int advice, vma_flags_t *vma_flags)
 {
 	return 0;
 }

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index a2c7c6a0768d..be1f779c8da5 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c

@@ -363,16 +363,16 @@ static unsigned int collapse_max_ptes_swap(struct collapse_control *cc,
 }
 
 int hugepage_madvise(struct vm_area_struct *vma,
-		     vm_flags_t *vm_flags, int advice)
+		     vma_flags_t *vma_flags, int advice)
 {
 	switch (advice) {
 	case MADV_HUGEPAGE:
-		*vm_flags &= ~VM_NOHUGEPAGE;
-		*vm_flags |= VM_HUGEPAGE;
+		vma_flags_clear(vma_flags, VMA_NOHUGEPAGE_BIT);
+		vma_flags_set(vma_flags, VMA_HUGEPAGE_BIT);
 		break;
 	case MADV_NOHUGEPAGE:
-		*vm_flags &= ~VM_HUGEPAGE;
-		*vm_flags |= VM_NOHUGEPAGE;
+		vma_flags_clear(vma_flags, VMA_HUGEPAGE_BIT);
+		vma_flags_set(vma_flags, VMA_NOHUGEPAGE_BIT);
 		/*
 		 * Setting VM_NOHUGEPAGE will prevent khugepaged from scanning
 		 * this vma even if we leave the mm registered in khugepaged if

diff --git a/mm/ksm.c b/mm/ksm.c
index 61b772bba229..3eb9c1ec2f87 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c

@@ -779,7 +779,8 @@ static struct vm_area_struct *find_mergeable_vma(struct mm_struct *mm,
 	if (ksm_test_exit(mm))
 		return NULL;
 	vma = vma_lookup(mm, addr);
-	if (!vma || !vma_test(vma, VMA_MERGEABLE_BIT) || !vma_has_anon_rmap(vma))
+	if (!vma || !vma_test(vma, VMA_MERGEABLE_BIT) ||
+	    !vma_has_anon_rmap(vma))
 		return NULL;
 	return vma;
 }

@@ -3021,7 +3022,7 @@ int ksm_disable(struct mm_struct *mm)
 }
 
 int ksm_madvise(struct vm_area_struct *vma, unsigned long start,
-		unsigned long end, int advice, vm_flags_t *vm_flags)
+		unsigned long end, int advice, vma_flags_t *vma_flags)
 {
 	struct mm_struct *mm = vma->vm_mm;
 	int err;

@@ -3039,11 +3040,11 @@ int ksm_madvise(struct vm_area_struct *vma, unsigned long start,
 				return err;
 		}
 
-		*vm_flags |= VM_MERGEABLE;
+		vma_flags_set(vma_flags, VMA_MERGEABLE_BIT);
 		break;
 
 	case MADV_UNMERGEABLE:
-		if (!(*vm_flags & VM_MERGEABLE))
+		if (!vma_flags_test(vma_flags, VMA_MERGEABLE_BIT))
 			return 0;		/* just ignore the advice */
 
 		if (vma_has_anon_rmap(vma)) {

@@ -3052,7 +3053,7 @@ int ksm_madvise(struct vm_area_struct *vma, unsigned long start,
 				return err;
 		}
 
-		*vm_flags &= ~VM_MERGEABLE;
+		vma_flags_clear(vma_flags, VMA_MERGEABLE_BIT);
 		break;
 	}

diff --git a/mm/madvise.c b/mm/madvise.c
index e9fa4f71efea..1b539e67b00d 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c

@@ -148,11 +148,10 @@ static int replace_anon_vma_name(struct vm_area_struct *vma,
  * Update the vm_flags or anon_name on region of a vma, splitting it or merging
  * it as necessary. Must be called with mmap_lock held for writing.
  */
-static int madvise_update_vma(vm_flags_t new_flags,
+static int madvise_update_vma(vma_flags_t new_vma_flags,
 		struct madvise_behavior *madv_behavior)
 {
 	struct vm_area_struct *vma = madv_behavior->vma;
-	vma_flags_t new_vma_flags = legacy_to_vma_flags(new_flags);
 	struct madvise_behavior_range *range = &madv_behavior->range;
 	struct anon_vma_name *anon_name = madv_behavior->anon_name;
 	bool set_new_anon_name = madv_behavior->behavior == __MADV_SET_ANON_VMA_NAME;

@@ -601,7 +600,8 @@ static void madvise_cold_page_range(struct mmu_gather *tlb,
 
 static inline bool can_madv_lru_vma(struct vm_area_struct *vma)
 {
-	return !(vma->vm_flags & (VM_LOCKED|VM_PFNMAP|VM_HUGETLB));
+	return !vma_test_any(vma, VMA_LOCKED_BIT, VMA_PFNMAP_BIT,
+			     VMA_HUGETLB_BIT);
 }
 
 static long madvise_cold(struct madvise_behavior *madv_behavior)

@@ -650,7 +650,7 @@ static long madvise_pageout(struct madvise_behavior *madv_behavior)
 	 * further to pageout dirty anon pages.
 	 */
 	if (!vma_is_anonymous(vma) && (!can_do_file_pageout(vma) &&
-				(vma->vm_flags & VM_MAYSHARE)))
+				vma_test(vma, VMA_MAYSHARE_BIT)))
 		return 0;
 
 	lru_add_drain();

@@ -881,12 +881,12 @@ bool madvise_dontneed_free_valid_vma(struct madvise_behavior *madv_behavior)
 	struct madvise_behavior_range *range = &madv_behavior->range;
 
 	if (!vma_is_hugetlb(vma)) {
-		unsigned int forbidden = VM_PFNMAP;
+		vma_flags_t forbidden = mk_vma_flags(VMA_PFNMAP_BIT);
 
 		if (behavior != MADV_DONTNEED_LOCKED)
-			forbidden |= VM_LOCKED;
+			vma_flags_set(&forbidden, VMA_LOCKED_BIT);
 
-		return !(vma->vm_flags & forbidden);
+		return !vma_test_any_mask(vma, forbidden);
 	}
 
 	if (behavior != MADV_DONTNEED && behavior != MADV_DONTNEED_LOCKED)

@@ -1021,7 +1021,7 @@ static long madvise_remove(struct madvise_behavior *madv_behavior)
 
 	mark_mmap_lock_dropped(madv_behavior);
 
-	if (vma->vm_flags & VM_LOCKED)
+	if (vma_test(vma, VMA_LOCKED_BIT))
 		return -EINVAL;
 
 	f = vma->vm_file;

@@ -1333,7 +1333,7 @@ static bool can_madvise_modify(struct madvise_behavior *madv_behavior)
 		return true;
 
 	/* If the user could write to the mapping anyway, then this is fine. */
-	if ((vma->vm_flags & VM_WRITE) &&
+	if (vma_test(vma, VMA_WRITE_BIT) &&
 	    arch_vma_access_permitted(vma, /* write= */ true,
 			/* execute= */ false, /* foreign= */ false))
 		return true;

@@ -1357,7 +1357,7 @@ static int madvise_vma_behavior(struct madvise_behavior *madv_behavior)
 {
 	int behavior = madv_behavior->behavior;
 	struct vm_area_struct *vma = madv_behavior->vma;
-	vm_flags_t new_flags = vma->vm_flags;
+	vma_flags_t new_flags = vma->flags;
 	struct madvise_behavior_range *range = &madv_behavior->range;
 	int error;

@@ -1388,44 +1388,47 @@ static int madvise_vma_behavior(struct madvise_behavior *madv_behavior)
 	/* The below behaviours update VMAs via madvise_update_vma(). */
 
 	case MADV_NORMAL:
-		new_flags = new_flags & ~VM_RAND_READ & ~VM_SEQ_READ;
+		vma_flags_clear(&new_flags, VMA_RAND_READ_BIT,
+				VMA_SEQ_READ_BIT);
 		break;
 	case MADV_SEQUENTIAL:
-		new_flags = (new_flags & ~VM_RAND_READ) | VM_SEQ_READ;
+		vma_flags_clear(&new_flags, VMA_RAND_READ_BIT);
+		vma_flags_set(&new_flags, VMA_SEQ_READ_BIT);
 		break;
 	case MADV_RANDOM:
-		new_flags = (new_flags & ~VM_SEQ_READ) | VM_RAND_READ;
+		vma_flags_clear(&new_flags, VMA_SEQ_READ_BIT);
+		vma_flags_set(&new_flags, VMA_RAND_READ_BIT);
 		break;
 	case MADV_DONTFORK:
-		new_flags |= VM_DONTCOPY;
+		vma_flags_set(&new_flags, VMA_DONTCOPY_BIT);
 		break;
 	case MADV_DOFORK:
 		if (!vma_is_mm_backed(vma) || vma_is_hugetlb(vma))
 			return -EINVAL;
-		new_flags &= ~VM_DONTCOPY;
+		vma_flags_clear(&new_flags, VMA_DONTCOPY_BIT);
 		break;
 	case MADV_WIPEONFORK:
 		/* MADV_WIPEONFORK is only supported on anonymous memory. */
-		if (vma->vm_file || new_flags & VM_SHARED)
+		if (vma->vm_file || vma_flags_test(&new_flags, VMA_SHARED_BIT))
 			return -EINVAL;
-		new_flags |= VM_WIPEONFORK;
+		vma_flags_set(&new_flags, VMA_WIPEONFORK_BIT);
 		break;
 	case MADV_KEEPONFORK:
-		if (new_flags & VM_DROPPABLE)
+		if (vma_flags_test_single_mask(&new_flags, VMA_DROPPABLE))
 			return -EINVAL;
-		new_flags &= ~VM_WIPEONFORK;
+		vma_flags_clear(&new_flags, VMA_WIPEONFORK_BIT);
 		break;
 	case MADV_DONTDUMP:
-		new_flags |= VM_DONTDUMP;
+		vma_flags_set(&new_flags, VMA_DONTDUMP_BIT);
 		break;
 	case MADV_DODUMP:
 		/* Only mm-backed memory can be meaningfully dumped. */
 		if (!vma_is_mm_backed(vma))
 			return -EINVAL;
 		/* Core mm may discard droppable memory at any time. */
-		if (new_flags & VM_DROPPABLE)
+		if (vma_flags_test_single_mask(&new_flags, VMA_DROPPABLE))
 			return -EINVAL;
-		new_flags &= ~VM_DONTDUMP;
+		vma_flags_clear(&new_flags, VMA_DONTDUMP_BIT);
 		break;
 	case MADV_MERGEABLE:
 	case MADV_UNMERGEABLE:

diff --git a/mm/mremap.c b/mm/mremap.c
index 0d06d7f37f19..5f4e7d1ce3b7 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c

@@ -1133,7 +1133,7 @@ static unsigned long prep_move_vma(struct vma_remap_struct *vrm)
 	struct vm_area_struct *vma = vrm->vma;
 	unsigned long old_addr = vrm->addr;
 	unsigned long old_len = vrm->old_len;
-	vm_flags_t dummy = vma->vm_flags;
+	vma_flags_t dummy = vma->flags;
 	const bool split_before = vma->vm_start != old_addr;
 	const bool split_after = vma->vm_end != old_addr + old_len;

-- 
2.56.0

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