hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff)
{
	struct vm_area_struct *vma;
	struct prio_tree_iter iter;

	vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) {
		unsigned long v_offset;

		/*
		 * Can the expression below overflow on 32-bit arches?
		 * No, because the prio_tree returns us only those vmas
		 * which overlap the truncated area starting at pgoff,
		 * and no vma on a 32-bit arch can span beyond the 4GB.
		 */
		if (vma->vm_pgoff < pgoff)
			v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
		else
			v_offset = 0;

		__unmap_hugepage_range(vma,
				vma->vm_start + v_offset, vma->vm_end, NULL);
	}
}
hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff)
{
	struct vm_area_struct *vma;
	struct prio_tree_iter iter;

	vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) {
		unsigned long v_offset;

		 
		if (vma->vm_pgoff < pgoff)
			v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
		else
			v_offset = 0;

		__unmap_hugepage_range(vma,
				vma->vm_start + v_offset, vma->vm_end, NULL);
	}
}