diff --git a/mm/internal.h b/mm/internal.h
index 2ab81c68be6c..c61a98d3b3c7 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -1005,11 +1005,9 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
 /*
  * mm/mmap.c
  */
-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 *,
-	struct file *, pgoff_t, struct mempolicy *, struct vm_userfaultfd_ctx,
-	struct anon_vma_name *);
+struct vm_area_struct *vma_merge_extend(struct vma_iterator *vmi,
+					struct vm_area_struct *vma,
+					unsigned long delta);
 
 enum {
 	/* mark page accessed */
diff --git a/mm/mmap.c b/mm/mmap.c
index e5e50e547ebf..3ea52451623b 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -860,13 +860,13 @@ can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
  * **** is not represented - it will be merged and the vma containing the
  *      area is returned, or the function will return NULL
  */
-struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm,
-			struct vm_area_struct *prev, unsigned long addr,
-			unsigned long end, unsigned long vm_flags,
-			struct anon_vma *anon_vma, struct file *file,
-			pgoff_t pgoff, struct mempolicy *policy,
-			struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
-			struct anon_vma_name *anon_name)
+static struct vm_area_struct
+*vma_merge(struct vma_iterator *vmi, struct mm_struct *mm,
+	   struct vm_area_struct *prev, unsigned long addr, unsigned long end,
+	   unsigned long vm_flags, struct anon_vma *anon_vma, struct file *file,
+	   pgoff_t pgoff, struct mempolicy *policy,
+	   struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
+	   struct anon_vma_name *anon_name)
 {
 	struct vm_area_struct *curr, *next, *res;
 	struct vm_area_struct *vma, *adjust, *remove, *remove2;
@@ -2499,6 +2499,23 @@ static struct vm_area_struct
 			 vma->vm_userfaultfd_ctx, anon_vma_name(vma));
 }
 
+/*
+ * Expand vma by delta bytes, potentially merging with an immediately adjacent
+ * VMA with identical properties.
+ */
+struct vm_area_struct *vma_merge_extend(struct vma_iterator *vmi,
+					struct vm_area_struct *vma,
+					unsigned long delta)
+{
+	pgoff_t pgoff = vma->vm_pgoff + vma_pages(vma);
+
+	/* vma is specified as prev, so case 1 or 2 will apply. */
+	return vma_merge(vmi, vma->vm_mm, vma, vma->vm_end, vma->vm_end + delta,
+			 vma->vm_flags, vma->anon_vma, vma->vm_file, pgoff,
+			 vma_policy(vma), vma->vm_userfaultfd_ctx,
+			 anon_vma_name(vma));
+}
+
 /*
  * do_vmi_align_munmap() - munmap the aligned region from @start to @end.
  * @vmi: The vma iterator
diff --git a/mm/mremap.c b/mm/mremap.c
index ce8a23ef325a..38d98465f3d8 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -1096,14 +1096,12 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
 	/* old_len exactly to the end of the area..
 	 */
 	if (old_len == vma->vm_end - addr) {
+		unsigned long delta = new_len - old_len;
+
 		/* can we just expand the current mapping? */
-		if (vma_expandable(vma, new_len - old_len)) {
-			long pages = (new_len - old_len) >> PAGE_SHIFT;
-			unsigned long extension_start = addr + old_len;
-			unsigned long extension_end = addr + new_len;
-			pgoff_t extension_pgoff = vma->vm_pgoff +
-				((extension_start - vma->vm_start) >> PAGE_SHIFT);
-			VMA_ITERATOR(vmi, mm, extension_start);
+		if (vma_expandable(vma, delta)) {
+			long pages = delta >> PAGE_SHIFT;
+			VMA_ITERATOR(vmi, mm, vma->vm_end);
 			long charged = 0;
 
 			if (vma->vm_flags & VM_ACCOUNT) {
@@ -1115,17 +1113,15 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
 			}
 
 			/*
-			 * Function vma_merge() is called on the extension we
-			 * are adding to the already existing vma, vma_merge()
-			 * will merge this extension with the already existing
-			 * vma (expand operation itself) and possibly also with
-			 * the next vma if it becomes adjacent to the expanded
-			 * vma and  otherwise compatible.
+			 * Function vma_merge_extend() is called on the
+			 * extension we are adding to the already existing vma,
+			 * vma_merge_extend() will merge this extension with the
+			 * already existing vma (expand operation itself) and
+			 * possibly also with the next vma if it becomes
+			 * adjacent to the expanded vma and otherwise
+			 * compatible.
 			 */
-			vma = vma_merge(&vmi, mm, vma, extension_start,
-				extension_end, vma->vm_flags, vma->anon_vma,
-				vma->vm_file, extension_pgoff, vma_policy(vma),
-				vma->vm_userfaultfd_ctx, anon_vma_name(vma));
+			vma = vma_merge_extend(&vmi, vma, delta);
 			if (!vma) {
 				vm_unacct_memory(charged);
 				ret = -ENOMEM;