static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
			      int buflen)
{
	struct pid_namespace *ns = dentry->d_sb->s_fs_info;
	pid_t tgid = task_tgid_nr_ns(current, ns);
	char tmp[PROC_NUMBUF];
	if (!tgid)
		return -ENOENT;
	sprintf(tmp, "%d", tgid);
	return vfs_readlink(dentry,buffer,buflen,tmp);
}