Re: [PATCH net-next 1/4] net: dsa: don't offload switchdev objects on ports that don't offload the bridge

From: Tobias Waldekranz <tobias@waldekranz.com>
To: Vladimir Oltean <olteanv@gmail.com>,
	"David S . Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	netdev@vger.kernel.org
Cc: Florian Fainelli <f.fainelli@gmail.com>,
	Andrew Lunn <andrew@lunn.ch>,
	Vivien Didelot <vivien.didelot@gmail.com>,
	Kurt Kanzenbach <kurt@linutronix.de>,
	Woojung Huh <woojung.huh@microchip.com>,
	UNGLinuxDriver@microchip.com, Sean Wang <sean.wang@mediatek.com>,
	Landen Chao <Landen.Chao@mediatek.com>,
	Claudiu Manoil <claudiu.manoil@nxp.com>,
	Alexandre Belloni <alexandre.belloni@bootlin.com>,
	George McCollister <george.mccollister@gmail.com>,
	DENG Qingfang <dqfext@gmail.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	Hauke Mehrtens <hauke@hauke-m.de>,
	Rasmus Villemoes <rasmus.villemoes@prevas.dk>,
	Oleksij Rempel <linux@rempel-privat.de>
Subject: Re: [PATCH net-next 1/4] net: dsa: don't offload switchdev objects on ports that don't offload the bridge
Date: Thu, 25 Feb 2021 20:23:38 +0100	[thread overview]
Message-ID: <87eeh4rlxh.fsf@waldekranz.com> (raw)
In-Reply-To: <20210214155326.1783266-2-olteanv@gmail.com>

On Sun, Feb 14, 2021 at 17:53, Vladimir Oltean <olteanv@gmail.com> wrote:
> From: Vladimir Oltean <vladimir.oltean@nxp.com>
>
> Starting with commit 058102a6e9eb ("net: dsa: Link aggregation support"),
> DSA warns that certain configurations of upper interfaces are not offloaded
> to hardware. When a DSA port does not offload a LAG interface, the
> dp->lag_dev pointer is always NULL. However the same cannot be said about
> offloading a bridge: dp->bridge_dev will get populated regardless of
> whether the driver can put the port into the bridge's forwarding domain
> or not.
>
> Instead of silently returning 0 if the driver doesn't implement
> .port_bridge_join, return -EOPNOTSUPP instead, and print a message via
> netlink extack that the configuration was not offloaded to hardware.
>
> Now we can use the check whether dp->bridge_dev is NULL in order to
> avoid offloading at all switchdev attributes and objects for ports that
> don't even offload the basic operation of switching. Those can still do
> the required L2 forwarding using the bridge software datapath, but
> enabling any hardware features specific to the bridge such as address
> learning would just ask for problems.
>
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
> ---

Reviewed-by: Tobias Waldekranz <tobias@waldekranz.com>