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Date:   Mon, 01 Mar 2021 07:56:25 +0100
From:   Martin Schiller <ms@dev.tdt.de>
To:     Xie He <xie.he.0141@gmail.com>
Cc:     Jakub Kicinski <kuba@kernel.org>,
        Leon Romanovsky <leon@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Linux X25 <linux-x25@vger.kernel.org>,
        Linux Kernel Network Developers <netdev@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Krzysztof Halasa <khc@pm.waw.pl>,
        Jonathan Corbet <corbet@lwn.net>, linux-doc@vger.kernel.org
Subject: Re: [PATCH net-next RFC v4] net: hdlc_x25: Queue outgoing LAPB frames
Organization: TDT AG
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On 2021-02-27 00:03, Xie He wrote:
> On Fri, Feb 26, 2021 at 6:21 AM Martin Schiller <ms@dev.tdt.de> wrote:
>> 
>> I have now had a look at it. It works as expected.
>> I just wonder if it would not be more appropriate to call
>> the lapb_register() already in x25_hdlc_open(), so that the layer2
>> (lapb) can already "work" before the hdlc<x>_x25 interface is up.
> 
> I think it's better not to keep LAPB running unless hdlc<x>_x25 is up.
> If I am the user, I would expect that when I change the X.25 interface
> to the DOWN state, the LAPB protocol would be completely stopped and
> the LAPB layer would not generate any new frames anymore (even if the
> other side wants to connect), and when I change the X.25 interface
> back to the UP state, it would be a fresh new start for the LAPB
> protocol.
> 
>> Also, I have a hard time assessing if such a wrap is really 
>> enforceable.
> 
> Sorry. I don't understand what you mean. What "wrap" are you referring 
> to?

I mean the change from only one hdlc<x> interface to both hdlc<x> and
hdlc<x>_x25.

I can't estimate how many users are out there and how their setup looks
like.

> 
>> Unfortunately I have no idea how many users there actually are.