mm/mmap: convert do_brk_flags() to use vma_prepare() and vma_complete()

Use the abstracted vma locking for do_brk_flags()

Link: https://lkml.kernel.org/r/20230120162650.984577-48-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/mmap.c

@@ -2936,6 +2936,7 @@ static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma,
 		unsigned long addr, unsigned long len, unsigned long flags)
 {
 	struct mm_struct *mm = current->mm;
+	struct vma_prepare vp;
 
 	validate_mm_mt(mm);
 	/*
@@ -2963,18 +2964,13 @@ static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma,
 			goto unacct_fail;
 
 		vma_adjust_trans_huge(vma, vma->vm_start, addr + len, 0);
-		if (vma->anon_vma) {
-			anon_vma_lock_write(vma->anon_vma);
-			anon_vma_interval_tree_pre_update_vma(vma);
-		}
+		init_vma_prep(&vp, vma);
+		vma_prepare(&vp);
 		vma->vm_end = addr + len;
 		vma->vm_flags |= VM_SOFTDIRTY;
 		vma_iter_store(vmi, vma);
 
-		if (vma->anon_vma) {
-			anon_vma_interval_tree_post_update_vma(vma);
-			anon_vma_unlock_write(vma->anon_vma);
-		}
+		vma_complete(&vp, vmi, mm);
 		khugepaged_enter_vma(vma, flags);
 		goto out;
 	}