netdev - Re: [PATCH V3 net-next 1/4] net: bridge: add fdb flag to extent locked port feature

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Date:   Thu, 02 Jun 2022 14:08:41 +0200
From:   Hans Schultz <schultz.hans@...il.com>
To:     Ido Schimmel <idosch@...dia.com>,
        Nikolay Aleksandrov <razor@...ckwall.org>
Cc:     Hans Schultz <schultz.hans@...il.com>,
        Ido Schimmel <idosch@...sch.org>, davem@...emloft.net,
        kuba@...nel.org, netdev@...r.kernel.org,
        Andrew Lunn <andrew@...n.ch>,
        Vivien Didelot <vivien.didelot@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Vladimir Oltean <olteanv@...il.com>,
        Eric Dumazet <edumazet@...gle.com>,
        Paolo Abeni <pabeni@...hat.com>, Jiri Pirko <jiri@...nulli.us>,
        Ivan Vecera <ivecera@...hat.com>,
        Roopa Prabhu <roopa@...dia.com>, Shuah Khan <shuah@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        linux-kernel@...r.kernel.org, bridge@...ts.linux-foundation.org,
        linux-kselftest@...r.kernel.org
Subject: Re: [PATCH V3 net-next 1/4] net: bridge: add fdb flag to extent
 locked port feature

>
> I think Hans is testing with mv88e6xxx which dumps entries directly from
> HW via ndo_fdb_dump(). See dsa_slave_port_fdb_do_dump() which sets
> NTF_SELF.
>
> Hans, are you seeing the entry twice? Once with 'master' and once with
> 'self'?
>

When replacing a locked entry it looks like this:

# bridge fdb show dev eth6 | grep 4c
00:4c:4c:4c:4c:4c vlan 1 master br0 extern_learn offload locked

# bridge fdb replace 00:4c:4c:4c:4c:4c dev eth6 vlan 1 master static ; bridge fdb show dev eth6 | grep 4c
00:4c:4c:4c:4c:4c vlan 1 self static

The problem is then that the function
br_fdb_find_rcu(br,eth_hdr(skb)->h_source, vid);
, where the h_source and vid is the entry above, does not find the entry.
My hypothesis was then that this is because of the 'self' flag that I
see.

I am thinking that the function dsa_slave_port_fdb_do_dump() is only for
debug, and thus does not really set any flags in the bridge modules FDB,
but then I don't understand why the above find function does not find
the entry?