Thread (43 messages) 43 messages, 5 authors, 21h ago

Re: [PATCH 13/13] mm/mremap: convert mremap code to use vma_flags_t

From: Lance Yang <lance.yang@linux.dev>
Date: 2026-07-02 13:50:26
Also in: dri-devel, intel-gfx, intel-xe, linux-arm-msm, linux-fbdev, linux-fsdevel, linux-mips, linux-samsung-soc, linux-sound, linux-tegra, lkml, nouveau, virtualization, xen-devel

On Mon, Jun 29, 2026 at 08:25:36PM +0100, Lorenzo Stoakes wrote:
Replace use of the legacy vm_flags_t flags with vma_flags_t values
throughout the mremap logic.

Additionally update comments to reflect the changes to be consistent.

No functional change intended.

Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
---
The vm_flags_set() cases below spell out vma_start_write(), but the
vm_flags_clear() cases don't?

Thanks, Lance
quoted hunk ↗ jump to hunk
mm/mremap.c | 38 ++++++++++++++++++++------------------
1 file changed, 20 insertions(+), 18 deletions(-)
diff --git a/mm/mremap.c b/mm/mremap.c
index 079a0ba0c4a7..0ea43302b7ed 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -68,7 +68,7 @@ struct vma_remap_struct {
	bool populate_expand;		/* mlock()'d expanded, must populate. */
	enum mremap_type remap_type;	/* expand, shrink, etc. */
	bool mmap_locked;		/* Is mm currently write-locked? */
-	unsigned long charged;		/* If VM_ACCOUNT, # pages to account. */
+	unsigned long charged;		/* If VMA_ACCOUNT_BIT, # pgs to account */
	bool vmi_needs_invalidate;	/* Is the VMA iterator invalidated? */
};
@@ -954,7 +954,7 @@ static unsigned long vrm_set_new_addr(struct vma_remap_struct *vrm)
	if (vrm->flags & MREMAP_FIXED)
		map_flags |= MAP_FIXED;
-	if (vma->vm_flags & VM_MAYSHARE)
+	if (vma_test(vma, VMA_MAYSHARE_BIT))
		map_flags |= MAP_SHARED;

	res = get_unmapped_area(vma->vm_file, new_addr, vrm->new_len, pgoff,
@@ -976,7 +976,7 @@ static bool vrm_calc_charge(struct vma_remap_struct *vrm)
{
	unsigned long charged;

-	if (!(vrm->vma->vm_flags & VM_ACCOUNT))
+	if (!vma_test(vrm->vma, VMA_ACCOUNT_BIT))
		return true;

	/*
@@ -1003,7 +1003,7 @@ static bool vrm_calc_charge(struct vma_remap_struct *vrm)
 */
static void vrm_uncharge(struct vma_remap_struct *vrm)
{
-	if (!(vrm->vma->vm_flags & VM_ACCOUNT))
+	if (!vma_test(vrm->vma, VMA_ACCOUNT_BIT))
		return;

	vm_unacct_memory(vrm->charged);
@@ -1023,7 +1023,7 @@ static void vrm_stat_account(struct vma_remap_struct *vrm,
	struct vm_area_struct *vma = vrm->vma;

	vm_stat_account(mm, vma->vm_flags, pages);
-	if (vma->vm_flags & VM_LOCKED)
+	if (vma_test(vma, VMA_LOCKED_BIT))
		mm->locked_vm += pages;
}
@@ -1167,7 +1167,7 @@ static void unmap_source_vma(struct vma_remap_struct *vrm)
	 * arose, in which case we _do_ wish to unmap the _new_ VMA, which means
	 * we actually _do_ want it be unaccounted.
	 */
-	bool accountable_move = (vma->vm_flags & VM_ACCOUNT) &&
+	bool accountable_move = vma_test(vma, VMA_ACCOUNT_BIT) &&
		!(vrm->flags & MREMAP_DONTUNMAP);

	/*
@@ -1186,7 +1186,7 @@ static void unmap_source_vma(struct vma_remap_struct *vrm)
	 * portions of the original VMA that remain.
	 */
	if (accountable_move) {
-		vm_flags_clear(vma, VM_ACCOUNT);
+		vma_clear_flags(vma, VMA_ACCOUNT_BIT);
		/* We are about to split vma, so store the start/end. */
		vm_start = vma->vm_start;
		vm_end = vma->vm_end;
@@ -1211,8 +1211,8 @@ static void unmap_source_vma(struct vma_remap_struct *vrm)
	 * |             |
	 * |-------------|
	 *
-	 * Having cleared VM_ACCOUNT from the whole VMA, after we unmap above
-	 * we'll end up with:
+	 * Having cleared VMA_ACCOUNT_BIT from the whole VMA, after we unmap
+	 * above we'll end up with:
	 *
	 *    addr  end
	 *     |     |
@@ -1232,13 +1232,15 @@ static void unmap_source_vma(struct vma_remap_struct *vrm)
		if (vm_start < addr) {
			struct vm_area_struct *prev = vma_prev(&vmi);

-			vm_flags_set(prev, VM_ACCOUNT); /* Acquires VMA lock. */
+			vma_start_write(prev);
+			vma_set_flags(prev, VMA_ACCOUNT_BIT);
		}

		if (vm_end > end) {
			struct vm_area_struct *next = vma_next(&vmi);

-			vm_flags_set(next, VM_ACCOUNT); /* Acquires VMA lock. */
+			vma_start_write(next);
+			vma_set_flags(next, VMA_ACCOUNT_BIT);
		}
	}
}
@@ -1321,8 +1323,8 @@ static void dontunmap_complete(struct vma_remap_struct *vrm,
	unsigned long old_start = vrm->vma->vm_start;
	unsigned long old_end = vrm->vma->vm_end;

-	/* We always clear VM_LOCKED[ONFAULT] on the old VMA. */
-	vm_flags_clear(vrm->vma, VM_LOCKED_MASK);
+	/* We always clear VMA_LOCKED[ONFAULT]_BIT on the old VMA. */
+	vma_clear_flags_mask(vrm->vma, VMA_LOCKED_MASK);

	/*
	 * anon_vma links of the old vma is no longer needed after its page
@@ -1758,14 +1760,14 @@ static int check_prep_vma(struct vma_remap_struct *vrm)
	 * based on the original.  There are no known use cases for this
	 * behavior.  As a result, fail such attempts.
	 */
-	if (!old_len && !(vma->vm_flags & (VM_SHARED | VM_MAYSHARE))) {
+	if (!old_len && !vma_test_any(vma, VMA_SHARED_BIT, VMA_MAYSHARE_BIT)) {
		pr_warn_once("%s (%d): attempted to duplicate a private mapping with mremap.  This is not supported.\n",
			     current->comm, current->pid);
		return -EINVAL;
	}

	if ((vrm->flags & MREMAP_DONTUNMAP) &&
-			(vma->vm_flags & (VM_DONTEXPAND | VM_PFNMAP)))
+	    vma_test_any(vma, VMA_DONTEXPAND_BIT, VMA_PFNMAP_BIT))
		return -EINVAL;

	/*
@@ -1795,7 +1797,7 @@ static int check_prep_vma(struct vma_remap_struct *vrm)
		return 0;

	/* We are expanding and the VMA is mlock()'d so we need to populate. */
-	if (vma->vm_flags & VM_LOCKED)
+	if (vma_test(vma, VMA_LOCKED_BIT))
		vrm->populate_expand = true;

	/* Need to be careful about a growing mapping */
@@ -1803,10 +1805,10 @@ static int check_prep_vma(struct vma_remap_struct *vrm)
	if (pgoff + (new_len >> PAGE_SHIFT) < pgoff)
		return -EINVAL;

-	if (vma->vm_flags & (VM_DONTEXPAND | VM_PFNMAP))
+	if (vma_test_any(vma, VMA_DONTEXPAND_BIT, VMA_PFNMAP_BIT))
		return -EFAULT;

-	if (!mlock_future_ok(mm, vma->vm_flags & VM_LOCKED, vrm->delta))
+	if (!mlock_future_ok(mm, vma_test(vma, VMA_LOCKED_BIT), vrm->delta))
		return -EAGAIN;

	if (!may_expand_vm(mm, &vma->flags, vrm->delta >> PAGE_SHIFT))
-- 
2.54.0
  
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