[PATCH 2/2] userfaultfd: make functions that are not used outside uffd static

Mike Rapoport
2026-04-30T11:35:27Z

From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>

After merging fs/userfaultfd.c into mm/userfaultfd.c, several functions
that were previously shared between the two files are now only used within
mm/userfaultfd.c.

Make them static and remove their declarations from
include/linux/userfaultfd_k.h.

Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Assisted-by: Copilot:claude-opus-4-6
---
include/linux/userfaultfd_k.h | 36 -----------------------------------
mm/userfaultfd.c | 24 +++++++++++------------
2 files changed, 12 insertions(+), 48 deletions(-)

diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h
index d2920f98ab86..3ec8e1071673 100644
--- a/include/linux/userfaultfd_k.h
+++ b/include/linux/userfaultfd_k.h
@@ -147,26 +147,12 @@ static inline uffd_flags_t uffd_flags_set_mode(uffd_flags_t flags, enum mfill_at
/* Flags controlling behavior. These behavior changes are mode-independent. */
#define MFILL_ATOMIC_WP MFILL_ATOMIC_FLAG(0)

-extern ssize_t mfill_atomic_copy(struct userfaultfd_ctx *ctx, unsigned long dst_start,
- unsigned long src_start, unsigned long len,
- uffd_flags_t flags);
-extern ssize_t mfill_atomic_zeropage(struct userfaultfd_ctx *ctx,
- unsigned long dst_start,
- unsigned long len);
-extern ssize_t mfill_atomic_continue(struct userfaultfd_ctx *ctx, unsigned long dst_start,
- unsigned long len, uffd_flags_t flags);
-extern ssize_t mfill_atomic_poison(struct userfaultfd_ctx *ctx, unsigned long start,
- unsigned long len, uffd_flags_t flags);
-extern int mwriteprotect_range(struct userfaultfd_ctx *ctx, unsigned long start,
- unsigned long len, bool enable_wp);
extern long uffd_wp_range(struct vm_area_struct *vma,
unsigned long start, unsigned long len, bool enable_wp);

/* move_pages */
void double_pt_lock(spinlock_t *ptl1, spinlock_t *ptl2);
void double_pt_unlock(spinlock_t *ptl1, spinlock_t *ptl2);
-ssize_t move_pages(struct userfaultfd_ctx *ctx, unsigned long dst_start,
- unsigned long src_start, unsigned long len, __u64 flags);
int move_pages_huge_pmd(struct mm_struct *mm, pmd_t *dst_pmd, pmd_t *src_pmd, pmd_t dst_pmdval,
struct vm_area_struct *dst_vma,
struct vm_area_struct *src_vma,
@@ -239,9 +225,6 @@ static inline bool userfaultfd_armed(struct vm_area_struct *vma)
return vma->vm_flags & __VM_UFFD_FLAGS;
}

-bool vma_can_userfault(struct vm_area_struct *vma, vm_flags_t vm_flags,
- bool wp_async);
-
static inline bool vma_has_uffd_without_event_remap(struct vm_area_struct *vma)
{
struct userfaultfd_ctx *uffd_ctx = vma->vm_userfaultfd_ctx.ctx;
@@ -271,25 +254,6 @@ extern void userfaultfd_unmap_complete(struct mm_struct *mm,
extern bool userfaultfd_wp_unpopulated(struct vm_area_struct *vma);
extern bool userfaultfd_wp_async(struct vm_area_struct *vma);

-void userfaultfd_reset_ctx(struct vm_area_struct *vma);
-
-struct vm_area_struct *userfaultfd_clear_vma(struct vma_iterator *vmi,
- struct vm_area_struct *prev,
- struct vm_area_struct *vma,
- unsigned long start,
- unsigned long end);
-
-int userfaultfd_register_range(struct userfaultfd_ctx *ctx,
- struct vm_area_struct *vma,
- vm_flags_t vm_flags,
- unsigned long start, unsigned long end,
- bool wp_async);
-
-void userfaultfd_release_new(struct userfaultfd_ctx *ctx);
-
-void userfaultfd_release_all(struct mm_struct *mm,
- struct userfaultfd_ctx *ctx);
-
static inline bool userfaultfd_wp_use_markers(struct vm_area_struct *vma)
{
/* Only wr-protect mode uses pte markers */
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index d0cf44aec1c4..f089ffa39722 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -958,7 +958,7 @@ static __always_inline ssize_t mfill_atomic(struct userfaultfd_ctx *ctx,
return copied ? copied : err;
}

-ssize_t mfill_atomic_copy(struct userfaultfd_ctx *ctx, unsigned long dst_start,
+static ssize_t mfill_atomic_copy(struct userfaultfd_ctx *ctx, unsigned long dst_start,
unsigned long src_start, unsigned long len,
uffd_flags_t flags)
{
@@ -966,7 +966,7 @@ ssize_t mfill_atomic_copy(struct userfaultfd_ctx *ctx, unsigned long dst_start,
uffd_flags_set_mode(flags, MFILL_ATOMIC_COPY));
}

-ssize_t mfill_atomic_zeropage(struct userfaultfd_ctx *ctx,
+static ssize_t mfill_atomic_zeropage(struct userfaultfd_ctx *ctx,
unsigned long start,
unsigned long len)
{
@@ -974,7 +974,7 @@ ssize_t mfill_atomic_zeropage(struct userfaultfd_ctx *ctx,
uffd_flags_set_mode(0, MFILL_ATOMIC_ZEROPAGE));
}

-ssize_t mfill_atomic_continue(struct userfaultfd_ctx *ctx, unsigned long start,
+static ssize_t mfill_atomic_continue(struct userfaultfd_ctx *ctx, unsigned long start,
unsigned long len, uffd_flags_t flags)
{

@@ -990,7 +990,7 @@ ssize_t mfill_atomic_continue(struct userfaultfd_ctx *ctx, unsigned long start,
uffd_flags_set_mode(flags, MFILL_ATOMIC_CONTINUE));
}

-ssize_t mfill_atomic_poison(struct userfaultfd_ctx *ctx, unsigned long start,
+static ssize_t mfill_atomic_poison(struct userfaultfd_ctx *ctx, unsigned long start,
unsigned long len, uffd_flags_t flags)
{
return mfill_atomic(ctx, start, 0, len,
@@ -1026,7 +1026,7 @@ long uffd_wp_range(struct vm_area_struct *dst_vma,
return ret;
}

-int mwriteprotect_range(struct userfaultfd_ctx *ctx, unsigned long start,
+static int mwriteprotect_range(struct userfaultfd_ctx *ctx, unsigned long start,
unsigned long len, bool enable_wp)
{
struct mm_struct *dst_mm = ctx->mm;
@@ -1856,7 +1856,7 @@ static void uffd_move_unlock(struct vm_area_struct *dst_vma,
* in the regions or not, but preventing the risk of having to split
* the hugepmd during the remap.
*/
-ssize_t move_pages(struct userfaultfd_ctx *ctx, unsigned long dst_start,
+static ssize_t move_pages(struct userfaultfd_ctx *ctx, unsigned long dst_start,
unsigned long src_start, unsigned long len, __u64 mode)
{
struct mm_struct *mm = ctx->mm;
@@ -2031,7 +2031,7 @@ ssize_t move_pages(struct userfaultfd_ctx *ctx, unsigned long dst_start,
return moved ? moved : err;
}

-bool vma_can_userfault(struct vm_area_struct *vma, vm_flags_t vm_flags,
+static bool vma_can_userfault(struct vm_area_struct *vma, vm_flags_t vm_flags,
bool wp_async)
{
const struct vm_uffd_ops *ops = vma_uffd_ops(vma);
@@ -2088,12 +2088,12 @@ static void userfaultfd_set_ctx(struct vm_area_struct *vma,
(vma->vm_flags & ~__VM_UFFD_FLAGS) | vm_flags);
}

-void userfaultfd_reset_ctx(struct vm_area_struct *vma)
+static void userfaultfd_reset_ctx(struct vm_area_struct *vma)
{
userfaultfd_set_ctx(vma, NULL, 0);
}

-struct vm_area_struct *userfaultfd_clear_vma(struct vma_iterator *vmi,
+static struct vm_area_struct *userfaultfd_clear_vma(struct vma_iterator *vmi,
struct vm_area_struct *prev,
struct vm_area_struct *vma,
unsigned long start,
@@ -2132,7 +2132,7 @@ struct vm_area_struct *userfaultfd_clear_vma(struct vma_iterator *vmi,
}

/* Assumes mmap write lock taken, and mm_struct pinned. */
-int userfaultfd_register_range(struct userfaultfd_ctx *ctx,
+static int userfaultfd_register_range(struct userfaultfd_ctx *ctx,
struct vm_area_struct *vma,
vm_flags_t vm_flags,
unsigned long start, unsigned long end,
@@ -2196,7 +2196,7 @@ int userfaultfd_register_range(struct userfaultfd_ctx *ctx,
return 0;
}

-void userfaultfd_release_new(struct userfaultfd_ctx *ctx)
+static void userfaultfd_release_new(struct userfaultfd_ctx *ctx)
{
struct mm_struct *mm = ctx->mm;
struct vm_area_struct *vma;
@@ -2211,7 +2211,7 @@ void userfaultfd_release_new(struct userfaultfd_ctx *ctx)
mmap_write_unlock(mm);
}

-void userfaultfd_release_all(struct mm_struct *mm,
+static void userfaultfd_release_all(struct mm_struct *mm,
struct userfaultfd_ctx *ctx)
{
struct vm_area_struct *vma, *prev;
--
2.53.0