On Fri, Mar 19, 2021 at 01:18, Vladimir Oltean <olteanv@xxxxxxxxx> wrote: > From: Vladimir Oltean <vladimir.oltean@xxxxxxx> > > It may happen that we have the following topology: > > ip link add br0 type bridge stp_state 1 > ip link add bond0 type bond > ip link set bond0 master br0 > ip link set swp0 master bond0 > ip link set swp1 master bond0 > > STP decides that it should put bond0 into the BLOCKING state, and > that's that. The ports that are actively listening for the switchdev > port attributes emitted for the bond0 bridge port (because they are > offloading it) and have the honor of seeing that switchdev port > attribute can react to it, so we can program swp0 and swp1 into the > BLOCKING state. > > But if then we do: > > ip link set swp2 master bond0 > > then as far as the bridge is concerned, nothing has changed: it still > has one bridge port. But this new bridge port will not see any STP state > change notification and will remain FORWARDING, which is how the > standalone code leaves it in. > > Add a function to the bridge which retrieves the current STP state, such > that drivers can synchronize to it when they may have missed switchdev > events. > > Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx> > --- Reviewed-by: Tobias Waldekranz <tobias@xxxxxxxxxxxxxx>
