mm/mmap: pass vma to vma_merge()

These vma_merge() callers will pass mm, anon_vma and file, they all from
the same vma.  There is no need to pass three parameters at the same time.

Pass vma instead of mm, anon_vma and file to vma_merge(), so that it can
save two parameters.

Link: https://lkml.kernel.org/r/20240203014632.2726545-1-yajun.deng@linux.dev
Link: https://lore.kernel.org/lkml/20240125034922.1004671-2-yajun.deng@linux.dev/
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Yajun Deng <yajun.deng@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/mmap.c

@@ -860,13 +860,15 @@ can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
  *      area is returned, or the function will return NULL
  */
 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,
+*vma_merge(struct vma_iterator *vmi, struct vm_area_struct *prev,
+	   struct vm_area_struct *src, unsigned long addr, unsigned long end,
+	   unsigned long vm_flags, pgoff_t pgoff, struct mempolicy *policy,
 	   struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
 	   struct anon_vma_name *anon_name)
 {
+	struct mm_struct *mm = src->vm_mm;
+	struct anon_vma *anon_vma = src->anon_vma;
+	struct file *file = src->vm_file;
 	struct vm_area_struct *curr, *next, *res;
 	struct vm_area_struct *vma, *adjust, *remove, *remove2;
 	struct vm_area_struct *anon_dup = NULL;
@@ -2426,9 +2428,8 @@ struct vm_area_struct *vma_modify(struct vma_iterator *vmi,
 	pgoff_t pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
 	struct vm_area_struct *merged;
 
-	merged = vma_merge(vmi, vma->vm_mm, prev, start, end, vm_flags,
-			   vma->anon_vma, vma->vm_file, pgoff, policy,
-			   uffd_ctx, anon_name);
+	merged = vma_merge(vmi, prev, vma, start, end, vm_flags,
+			   pgoff, policy, uffd_ctx, anon_name);
 	if (merged)
 		return merged;
 
@@ -2458,9 +2459,8 @@ static struct vm_area_struct
 		   struct vm_area_struct *vma, unsigned long start,
 		   unsigned long end, pgoff_t pgoff)
 {
-	return vma_merge(vmi, vma->vm_mm, prev, start, end, vma->vm_flags,
-			 vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
-			 vma->vm_userfaultfd_ctx, anon_vma_name(vma));
+	return vma_merge(vmi, prev, vma, start, end, vma->vm_flags, pgoff,
+			 vma_policy(vma), vma->vm_userfaultfd_ctx, anon_vma_name(vma));
 }
 
 /*
@@ -2474,10 +2474,9 @@ struct vm_area_struct *vma_merge_extend(struct vma_iterator *vmi,
 	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));
+	return vma_merge(vmi, vma, vma, vma->vm_end, vma->vm_end + delta,
+			 vma->vm_flags, pgoff, vma_policy(vma),
+			 vma->vm_userfaultfd_ctx, anon_vma_name(vma));
 }
 
 /*