userfaultfd: make functions that are not used outside uffd static

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.

Link: https://lore.kernel.org/20260523173759.3964908-3-rppt@kernel.org
Assisted-by: Copilot:claude-opus-4-6
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

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 74af5682f3fb..c86daf38d154 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -1033,7 +1033,7 @@ out:
 	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)
 {
@@ -1041,7 +1041,7 @@ 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)
 {
@@ -1049,7 +1049,7 @@ 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)
 {
 
@@ -1065,7 +1065,7 @@ 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,
@@ -1101,7 +1101,7 @@ 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;
@@ -1931,7 +1931,7 @@ 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;
@@ -2106,7 +2106,7 @@ out:
 	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);
@@ -2163,12 +2163,12 @@ 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,
@@ -2207,7 +2207,7 @@ 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,
@@ -2271,7 +2271,7 @@ skip:
 	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;
@@ -2286,7 +2286,7 @@ 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;