netdev - Re: [PATCH v8 net-next 10/12] net: dsa: mv88e6xxx: mac-auth/MAB implementation

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Date:   Thu, 20 Oct 2022 23:09:40 +0200
From:   netdev@...io-technology.com
To:     Vladimir Oltean <olteanv@...il.com>
Cc:     davem@...emloft.net, kuba@...nel.org, netdev@...r.kernel.org,
        Florian Fainelli <f.fainelli@...il.com>,
        Andrew Lunn <andrew@...n.ch>,
        Vivien Didelot <vivien.didelot@...il.com>,
        Eric Dumazet <edumazet@...gle.com>,
        Paolo Abeni <pabeni@...hat.com>,
        Kurt Kanzenbach <kurt@...utronix.de>,
        Hauke Mehrtens <hauke@...ke-m.de>,
        Woojung Huh <woojung.huh@...rochip.com>,
        UNGLinuxDriver@...rochip.com, Sean Wang <sean.wang@...iatek.com>,
        Landen Chao <Landen.Chao@...iatek.com>,
        DENG Qingfang <dqfext@...il.com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Claudiu Manoil <claudiu.manoil@....com>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Jiri Pirko <jiri@...nulli.us>,
        Ivan Vecera <ivecera@...hat.com>,
        Roopa Prabhu <roopa@...dia.com>,
        Nikolay Aleksandrov <razor@...ckwall.org>,
        Shuah Khan <shuah@...nel.org>,
        Russell King <linux@...linux.org.uk>,
        Christian Marangi <ansuelsmth@...il.com>,
        Daniel Borkmann <daniel@...earbox.net>,
        Yuwei Wang <wangyuweihx@...il.com>,
        Petr Machata <petrm@...dia.com>,
        Ido Schimmel <idosch@...dia.com>,
        Florent Fourcot <florent.fourcot@...irst.fr>,
        Hans Schultz <schultz.hans@...il.com>,
        Joachim Wiberg <troglobit@...il.com>,
        Amit Cohen <amcohen@...dia.com>, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org,
        bridge@...ts.linux-foundation.org, linux-kselftest@...r.kernel.org
Subject: Re: [PATCH v8 net-next 10/12] net: dsa: mv88e6xxx: mac-auth/MAB
 implementation

On 2022-10-20 15:25, Vladimir Oltean wrote:
> 
> This would not have been needed if dsa_port_set_state() would have
> called dsa_port_fast_age().
> 
> Currently it only does that if dp->learning is true. From previous
> conversations I get the idea that with MAB, port learning will be 
> false.
> But I don't understand why; isn't MAB CPU-assisted learning? I'm 
> looking
> at the ocelot hardware support for this and I think it could be
> implemented using a similar mechanism, but I certainly don't want to 
> add
> more workarounds such as this in other drivers.
> 
> Are there any other ways to implement MAB other than through CPU
> assisted learning?
> 
> We could add one more dp->mab flag which tracks the "mab" brport flag,
> and extend dsa_port_set_state() to also call dsa_port_fast_age() in 
> that
> case, but I want to make sure there isn't something extremely obvious
> I'm missing about the "learning" flag.
> 

As learning is off on locked ports, see other response, your dp->mab 
flag
idea might be a way to go, just need confirmation that this is needed.


>> @@ -6572,8 +6604,10 @@ static int mv88e6xxx_port_bridge_flags(struct 
>> dsa_switch *ds, int port,
>>  	if (flags.mask & BR_MCAST_FLOOD) {
>>  		bool multicast = !!(flags.val & BR_MCAST_FLOOD);
>> 
>> +		mv88e6xxx_reg_lock(chip);
>>  		err = chip->info->ops->port_set_mcast_flood(chip, port,
>>  							    multicast);
>> +		mv88e6xxx_reg_unlock(chip);
>>  		if (err)
>>  			goto out;
>>  	}
>> @@ -6581,20 +6615,34 @@ static int mv88e6xxx_port_bridge_flags(struct 
>> dsa_switch *ds, int port,
>>  	if (flags.mask & BR_BCAST_FLOOD) {
>>  		bool broadcast = !!(flags.val & BR_BCAST_FLOOD);
>> 
>> +		mv88e6xxx_reg_lock(chip);
>>  		err = mv88e6xxx_port_broadcast_sync(chip, port, broadcast);
>> +		mv88e6xxx_reg_unlock(chip);
>>  		if (err)
>>  			goto out;
>>  	}
>> 
>> +	if (flags.mask & BR_PORT_MAB) {
>> +		chip->ports[port].mab = !!(flags.val & BR_PORT_MAB);
>> +
>> +		if (!chip->ports[port].mab)
>> +			err = mv88e6xxx_atu_locked_entry_flush(ds, port);
>> +		else
>> +			err = 0;
> 
> Again, dsa_port_fast_age() is also called when dp->learning is turned
> off in dsa_port_bridge_flags(). I don't want to see the mv88e6xxx 
> driver
> doing this manually.
> 

Maybe I am wrong, but I have only been able to trigger fast ageing by 
setting
the STP state of the port to blocked...