Re: [PATCH net-next v2 2/3] net: dsa: ignore the old ageing time of the port being changed

[Andrew Lunn <andrew@lunn.ch>]

On Sun, Nov 15, 2026 at 11:59:52AM +0100, Oleksij Rempel wrote:
> Pass the port to the ageing time notifier. When
> dsa_switch_fastest_ageing_time() takes the minimum, skip the cached
> dp->ageing_time of that port and use the requested value instead. DSA
> updates the cache only after the notifier.
> 
> Without this, the minimum includes the port's old ageing time. During
> an STP topology change, the bridge lowers the ageing time to
> 2 x forward_delay (8 s with forward_delay 4 s). When it restores the
> configured value, DSA programs the cached 8 s again, and the switch
> keeps ageing at 8 s.
> 
> An automated review of the lan9645x bridge series pointed this out [1].
> I reproduced it on a KSZ9893 and tested the fix there.
> 
> Fixes: 77b61365ecef ("net: dsa: remove the transactional logic from ageing time notifiers")
> Link: https://lore.kernel.org/netdev/179180428624.434549.14425623884223795761@kernel.org/ [1]
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew