mm/mremap: convert vma_adjust() to vma_expand()

Stop using vma_adjust() in preparation for removing the function.  Export
vma_expand() to use instead.

Link: https://lkml.kernel.org/r/20230120162650.984577-45-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/mm.h

@@ -2839,6 +2839,9 @@ static inline int vma_adjust(struct vma_iterator *vmi,
 {
 	return __vma_adjust(vmi, vma, start, end, pgoff, NULL);
 }
+extern int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma,
+		      unsigned long start, unsigned long end, pgoff_t pgoff,
+		      struct vm_area_struct *next);
 extern struct vm_area_struct *vma_merge(struct vma_iterator *vmi,
 	struct mm_struct *, struct vm_area_struct *prev, unsigned long addr,
 	unsigned long end, unsigned long vm_flags, struct anon_vma *,

mm/mmap.c

@@ -634,9 +634,9 @@ static inline void vma_complete(struct vma_prepare *vp,
  *
  * Returns: 0 on success
  */
-inline int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma,
-		      unsigned long start, unsigned long end, pgoff_t pgoff,
-		      struct vm_area_struct *next)
+int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma,
+	       unsigned long start, unsigned long end, pgoff_t pgoff,
+	       struct vm_area_struct *next)
 {
 	bool remove_next = false;
 	struct vma_prepare vp;

mm/mremap.c

@@ -1053,8 +1053,8 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
 					extension_end, vma->vm_flags, vma->anon_vma,
 					vma->vm_file, extension_pgoff, vma_policy(vma),
 					vma->vm_userfaultfd_ctx, anon_vma_name(vma));
-			} else if (vma_adjust(&vmi, vma, vma->vm_start,
-					addr + new_len, vma->vm_pgoff)) {
+			} else if (vma_expand(&vmi, vma, vma->vm_start,
+					addr + new_len, vma->vm_pgoff, NULL)) {
 				vma = NULL;
 			}
 			if (!vma) {