[PATCH v2 07/13] mm: update secretmem to use VMA flags on mmap_prepare

Lorenzo Stoakes
2026-01-22T16:08:45Z

This patch updates secretmem to use the new vma_flags_t type which will
soon supersede vm_flags_t altogether.

In order to make this change we also have to update mlock_future_ok(), we
replace the vm_flags_t parameter with a simple boolean is_vma_locked one,
which also simplifies the invocation here.

This is laying the groundwork for eliminating the vm_flags_t in
vm_area_desc and more broadly throughout the kernel.

No functional changes intended.

Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
---
mm/internal.h | 2 +-
mm/mmap.c | 8 ++++----
mm/mremap.c | 2 +-
mm/secretmem.c | 7 +++----
mm/vma.c | 2 +-
5 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/mm/internal.h b/mm/internal.h
index ef71a1d9991f..d67e8bb75734 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -1046,7 +1046,7 @@ extern long populate_vma_page_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end, int *locked);
extern long faultin_page_range(struct mm_struct *mm, unsigned long start,
unsigned long end, bool write, int *locked);
-bool mlock_future_ok(const struct mm_struct *mm, vm_flags_t vm_flags,
+bool mlock_future_ok(const struct mm_struct *mm, bool is_vma_locked,
unsigned long bytes);

/*
diff --git a/mm/mmap.c b/mm/mmap.c
index 038ff5f09df0..354479c95896 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -225,12 +225,12 @@ static inline unsigned long round_hint_to_min(unsigned long hint)
return hint;
}

-bool mlock_future_ok(const struct mm_struct *mm, vm_flags_t vm_flags,
- unsigned long bytes)
+bool mlock_future_ok(const struct mm_struct *mm, bool is_vma_locked,
+ unsigned long bytes)
{
unsigned long locked_pages, limit_pages;

- if (!(vm_flags & VM_LOCKED) || capable(CAP_IPC_LOCK))
+ if (!is_vma_locked || capable(CAP_IPC_LOCK))
return true;

locked_pages = bytes >> PAGE_SHIFT;
@@ -416,7 +416,7 @@ unsigned long do_mmap(struct file *file, unsigned long addr,
if (!can_do_mlock())
return -EPERM;

- if (!mlock_future_ok(mm, vm_flags, len))
+ if (!mlock_future_ok(mm, vm_flags & VM_LOCKED, len))
return -EAGAIN;

if (file) {
diff --git a/mm/mremap.c b/mm/mremap.c
index 8391ae17de64..2be876a70cc0 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -1740,7 +1740,7 @@ static int check_prep_vma(struct vma_remap_struct *vrm)
if (vma->vm_flags & (VM_DONTEXPAND | VM_PFNMAP))
return -EFAULT;

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

if (!may_expand_vm(mm, vma->vm_flags, vrm->delta >> PAGE_SHIFT))
diff --git a/mm/secretmem.c b/mm/secretmem.c
index edf111e0a1bb..11a779c812a7 100644
--- a/mm/secretmem.c
+++ b/mm/secretmem.c
@@ -122,13 +122,12 @@ static int secretmem_mmap_prepare(struct vm_area_desc *desc)
{
const unsigned long len = vma_desc_size(desc);

- if ((desc->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0)
+ if (!vma_desc_test_flags(desc, VMA_SHARED_BIT, VMA_MAYSHARE_BIT))
return -EINVAL;

- if (!mlock_future_ok(desc->mm, desc->vm_flags | VM_LOCKED, len))
+ vma_desc_set_flags(desc, VMA_LOCKED_BIT, VMA_DONTDUMP_BIT);
+ if (!mlock_future_ok(desc->mm, /*is_vma_locked=*/ true, len))
return -EAGAIN;
-
- desc->vm_flags |= VM_LOCKED | VM_DONTDUMP;
desc->vm_ops = &secretmem_vm_ops;

return 0;
diff --git a/mm/vma.c b/mm/vma.c
index f352d5c72212..39dcd9ddd4ba 100644
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -3053,7 +3053,7 @@ static int acct_stack_growth(struct vm_area_struct *vma,
return -ENOMEM;

/* mlock limit tests */
- if (!mlock_future_ok(mm, vma->vm_flags, grow << PAGE_SHIFT))
+ if (!mlock_future_ok(mm, vma->vm_flags & VM_LOCKED, grow << PAGE_SHIFT))
return -ENOMEM;

/* Check to ensure the stack will not grow into a hugetlb-only region */
--
2.52.0