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Date:   Wed, 31 Aug 2022 20:50:20 -0700
From:   Jakub Kicinski <kuba@kernel.org>
To:     Vladimir Oltean <vladimir.oltean@nxp.com>
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Paolo Abeni <pabeni@redhat.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Vivien Didelot <vivien.didelot@gmail.com>,
        Andrew Lunn <andrew@lunn.ch>,
        Vladimir Oltean <olteanv@gmail.com>,
        Claudiu Manoil <claudiu.manoil@nxp.com>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        UNGLinuxDriver@microchip.com,
        Colin Foster <colin.foster@in-advantage.com>,
        Roopa Prabhu <roopa@nvidia.com>,
        Nikolay Aleksandrov <razor@blackwall.org>,
        Tobias Waldekranz <tobias@waldekranz.com>,
        Marek =?UTF-8?B?QmVow7pu?= <kabel@kernel.org>,
        Ansuel Smith <ansuelsmth@gmail.com>,
        DENG Qingfang <dqfext@gmail.com>,
        Alvin =?UTF-8?B?xaBpcHJhZ2E=?= <alsi@bang-olufsen.dk>,
        Linus Walleij <linus.walleij@linaro.org>,
        Luiz Angelo Daros de Luca <luizluca@gmail.com>,
        Felix Fietkau <nbd@nbd.name>, John Crispin <john@phrozen.org>,
        Sean Wang <sean.wang@mediatek.com>
Subject: Re: [PATCH net-next 3/9] net: dsa: allow the DSA master to be seen
 and changed through rtnetlink
Message-ID: <20220831205020.28fbfcc5@kernel.org>
In-Reply-To: <20220830195932.683432-4-vladimir.oltean@nxp.com>
References: <20220830195932.683432-1-vladimir.oltean@nxp.com>
        <20220830195932.683432-4-vladimir.oltean@nxp.com>
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On Tue, 30 Aug 2022 22:59:26 +0300 Vladimir Oltean wrote:
> Some DSA switches have multiple CPU ports, which can be used to improve
> CPU termination throughput, but DSA, through dsa_tree_setup_cpu_ports(),
> sets up only the first one, leading to suboptimal use of hardware.
>=20
> The desire is to not change the default configuration but to permit the
> user to create a dynamic mapping between individual user ports and the
> CPU port that they are served by, configurable through rtnetlink. It is
> also intended to permit load balancing between CPU ports, and in that
> case, the foreseen model is for the DSA master to be a bonding interface
> whose lowers are the physical DSA masters.
>=20
> To that end, we create a struct rtnl_link_ops for DSA user ports with
> the "dsa" kind. We expose the IFLA_DSA_MASTER link attribute that
> contains the ifindex of the newly desired DSA master.

net/dsa/port.c: In function =E2=80=98dsa_port_change_master=E2=80=99:
net/dsa/port.c:1414:13: warning: unused variable =E2=80=98port=E2=80=99 [-W=
unused-variable]
 1414 |         int port =3D dp->index;
      |             ^~~~

I presume you had a look around what side effects setting rtnl_link_ops
will have? Should .netns_refund be true?