COMPAT_SYSCALL_DEFINE4(migrate_pages, compat_pid_t, pid,
		       compat_ulong_t, maxnode,
		       const compat_ulong_t __user *, old_nodes,
		       const compat_ulong_t __user *, new_nodes)
{
	unsigned long __user *old = NULL;
	unsigned long __user *new = NULL;
	nodemask_t tmp_mask;
	unsigned long nr_bits;
	unsigned long size;

	nr_bits = min_t(unsigned long, maxnode - 1, MAX_NUMNODES);
	size = ALIGN(nr_bits, BITS_PER_LONG) / 8;
	if (old_nodes) {
		if (compat_get_bitmap(nodes_addr(tmp_mask), old_nodes, nr_bits))
			return -EFAULT;
		old = compat_alloc_user_space(new_nodes ? size * 2 : size);
		if (new_nodes)
			new = old + size / sizeof(unsigned long);
		if (copy_to_user(old, nodes_addr(tmp_mask), size))
			return -EFAULT;
	}
	if (new_nodes) {
		if (compat_get_bitmap(nodes_addr(tmp_mask), new_nodes, nr_bits))
			return -EFAULT;
		if (new == NULL)
			new = compat_alloc_user_space(size);
		if (copy_to_user(new, nodes_addr(tmp_mask), size))
			return -EFAULT;
	}
	return kernel_migrate_pages(pid, nr_bits + 1, old, new);
}