From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <netdev-owner@vger.kernel.org>
Received: from shards.monkeyblade.net ([184.105.139.130]:33298 "EHLO
        shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1751956AbeCLQ1o (ORCPT
        <rfc822;netdev@vger.kernel.org>); Mon, 12 Mar 2018 12:27:44 -0400
Date: Mon, 12 Mar 2018 12:27:40 -0400 (EDT)
Message-Id: <20180312.122740.1516455994852523532.davem@davemloft.net>
To: sd@queasysnail.net
Cc: netdev@vger.kernel.org, sbrivio@redhat.com
Subject: Re: [PATCH net] ipv4: lock mtu in fnhe when received PMTU <
 net.ipv4.route.min_pmtu
From: David Miller <davem@davemloft.net>
In-Reply-To: <20180312160528.GA30326@bistromath.localdomain>
References: <7db505e856b96802375c2e3e822fdc5a3cf66b65.1520613617.git.sd@queasysnail.net>
        <20180309.160619.741646019216536916.davem@davemloft.net>
        <20180312160528.GA30326@bistromath.localdomain>
Mime-Version: 1.0
Content-Type: Text/Plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Sender: netdev-owner@vger.kernel.org
List-ID: <netdev.vger.kernel.org>

From: Sabrina Dubroca <sd@queasysnail.net>
Date: Mon, 12 Mar 2018 17:05:28 +0100

> 2018-03-09, 16:06:19 -0500, David Miller wrote:
>> From: Sabrina Dubroca <sd@queasysnail.net>
>> Date: Fri,  9 Mar 2018 17:43:21 +0100
>> 
>> I think if you just choose an unused RTCF_* bit (f.e. 0x02000000) for
>> the state, you can use that because values propagate into the
>> rtable->rt_flags, and do not propagate out.  So you should be able to
>> use it in this way privately inside the kernel.
> 
> What about a bitfield?
> 
> -	u32			rt_pmtu;
> +	u32			rt_mtu_locked:1,
> +				rt_pmtu:31;

I guess that's fine.