linux-kernel - Re: [PATCH v2 net] net: bridge: switchdev: don't notify FDB entries with "master dynamic"

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Message-ID: <20230424122631.d7kwfwmlwvqjo3pz@skbuf>
Date:   Mon, 24 Apr 2023 15:26:31 +0300
From:   Vladimir Oltean <vladimir.oltean@....com>
To:     Hans Schultz <netdev@...io-technology.com>
Cc:     netdev@...r.kernel.org, Jakub Kicinski <kuba@...nel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Paolo Abeni <pabeni@...hat.com>,
        Ido Schimmel <idosch@...dia.com>,
        Roopa Prabhu <roopa@...dia.com>,
        Nikolay Aleksandrov <razor@...ckwall.org>,
        Ivan Vecera <ivecera@...hat.com>,
        Jiri Pirko <jiri@...nulli.us>,
        Jesse Brandeburg <jesse.brandeburg@...el.com>,
        bridge@...ts.linux-foundation.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 net] net: bridge: switchdev: don't notify FDB entries
 with "master dynamic"

On Sun, Apr 23, 2023 at 10:47:15AM +0200, Hans Schultz wrote:
> I do not understand this patch. It seems to me that it basically blocks
> any future use of dynamic fdb entries from userspace towards drivers.
> 
> I would have expected that something would be done in the DSA layer,
> where (switchcore) drivers would be able to set some flags to indicate
> which features are supported by the driver, including non-static
> fdb entries. But as the placement here is earlier in the datapath from
> userspace towards drivers it's not possible to do any such thing in the
> DSA layer wrt non-static fdb entries.

As explained too many times already in the thread here:
https://patchwork.kernel.org/project/netdevbpf/patch/20230318141010.513424-3-netdev@kapio-technology.com/
the plan is:

| Just like commit 6ab4c3117aec ("net: bridge: don't notify switchdev for
| local FDB addresses"), we could deny that for stable kernels, and add
| the correct interpretation of the flag in net-next.

Obviously we have not reached the end of that plan, and net-next is closed now.