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Subject: Re: [PATCH v5 net-next 05/10] net: switchdev: pass flags and mask to
 both {PRE_,}BRIDGE_FLAGS attributes
To:     Vladimir Oltean <olteanv@gmail.com>,
        Jakub Kicinski <kuba@kernel.org>,
        "David S. Miller" <davem@davemloft.net>
Cc:     Andrew Lunn <andrew@lunn.ch>,
        Vivien Didelot <vivien.didelot@gmail.com>,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        bridge@lists.linux-foundation.org, Roopa Prabhu <roopa@nvidia.com>,
        Nikolay Aleksandrov <nikolay@nvidia.com>,
        Jiri Pirko <jiri@resnulli.us>,
        Ido Schimmel <idosch@idosch.org>,
        Claudiu Manoil <claudiu.manoil@nxp.com>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        UNGLinuxDriver@microchip.com, Vadym Kochan <vkochan@marvell.com>,
        Taras Chornyi <tchornyi@marvell.com>,
        Grygorii Strashko <grygorii.strashko@ti.com>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        Ioana Ciornei <ioana.ciornei@nxp.com>,
        Ivan Vecera <ivecera@redhat.com>, linux-omap@vger.kernel.org
References: <20210212151600.3357121-1-olteanv@gmail.com>
 <20210212151600.3357121-6-olteanv@gmail.com>
From:   Florian Fainelli <f.fainelli@gmail.com>
Message-ID: <9a1efd0d-9930-cbc7-5450-ffb47a0034e4@gmail.com>
Date:   Fri, 12 Feb 2021 10:10:37 -0800
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On 2/12/2021 7:15 AM, Vladimir Oltean wrote:
> From: Vladimir Oltean <vladimir.oltean@nxp.com>
> 
> This switchdev attribute offers a counterproductive API for a driver
> writer, because although br_switchdev_set_port_flag gets passed a
> "flags" and a "mask", those are passed piecemeal to the driver, so while
> the PRE_BRIDGE_FLAGS listener knows what changed because it has the
> "mask", the BRIDGE_FLAGS listener doesn't, because it only has the final
> value. But certain drivers can offload only certain combinations of
> settings, like for example they cannot change unicast flooding
> independently of multicast flooding - they must be both on or both off.
> The way the information is passed to switchdev makes drivers not
> expressive enough, and unable to reject this request ahead of time, in
> the PRE_BRIDGE_FLAGS notifier, so they are forced to reject it during
> the deferred BRIDGE_FLAGS attribute, where the rejection is currently
> ignored.
> 
> This patch also changes drivers to make use of the "mask" field for edge
> detection when possible.
> 
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian