Ido Schimmel
2022-Oct-20 13:24 UTC
[Bridge] [PATCH v8 net-next 05/12] net: dsa: propagate the locked flag down through the DSA layer
On Thu, Oct 20, 2022 at 04:02:24PM +0300, Vladimir Oltean wrote:> On Tue, Oct 18, 2022 at 06:56:12PM +0200, Hans J. Schultz wrote: > > @@ -3315,6 +3316,7 @@ static int dsa_slave_fdb_event(struct net_device *dev, > > struct dsa_port *dp = dsa_slave_to_port(dev); > > bool host_addr = fdb_info->is_local; > > struct dsa_switch *ds = dp->ds; > > + u16 fdb_flags = 0; > > > > if (ctx && ctx != dp) > > return 0; > > @@ -3361,6 +3363,9 @@ static int dsa_slave_fdb_event(struct net_device *dev, > > orig_dev->name, fdb_info->addr, fdb_info->vid, > > host_addr ? " as host address" : ""); > > > > + if (fdb_info->locked) > > + fdb_flags |= DSA_FDB_FLAG_LOCKED; > > This is the bridge->driver direction. In which of the changes up until > now/through which mechanism will the bridge emit a > SWITCHDEV_FDB_ADD_TO_DEVICE with fdb_info->locked = true?I believe it can happen in the following call chain: br_handle_frame_finish br_fdb_update // p->flags & BR_PORT_MAB fdb_notify br_switchdev_fdb_notify This can happen with Spectrum when a packet ingresses via a locked port and incurs an FDB miss in hardware. The packet will be trapped and injected to the Rx path where it should invoke the above call chain.> Don't the other switchdev drivers except DSA (search for SWITCHDEV_FDB_EVENT_TO_DEVICE > in the drivers/ folder) need to handle this new flag too, even if to reject it?Yes, agree. At least with mlxsw it is not a big deal right now because it ignores entries with !BR_FDB_ADDED_BY_USER and locked entries are always like that, but it would be good to make it more explicit.> > When other drivers will want to look at fdb_info->locked, they'll have > the surprise that it's impossible to maintain backwards compatibility, > because they didn't use to treat the flag at all in the past (so either > locked or unlocked, they did the same thing). > > > + > > INIT_WORK(&switchdev_work->work, dsa_slave_switchdev_event_work); > > switchdev_work->event = event; > > switchdev_work->dev = dev; > > @@ -3369,6 +3374,7 @@ static int dsa_slave_fdb_event(struct net_device *dev, > > ether_addr_copy(switchdev_work->addr, fdb_info->addr); > > switchdev_work->vid = fdb_info->vid; > > switchdev_work->host_addr = host_addr; > > + switchdev_work->fdb_flags = fdb_flags;
Vladimir Oltean
2022-Oct-20 13:35 UTC
[Bridge] [PATCH v8 net-next 05/12] net: dsa: propagate the locked flag down through the DSA layer
On Thu, Oct 20, 2022 at 04:24:16PM +0300, Ido Schimmel wrote:> On Thu, Oct 20, 2022 at 04:02:24PM +0300, Vladimir Oltean wrote: > > On Tue, Oct 18, 2022 at 06:56:12PM +0200, Hans J. Schultz wrote: > > > @@ -3315,6 +3316,7 @@ static int dsa_slave_fdb_event(struct net_device *dev, > > > struct dsa_port *dp = dsa_slave_to_port(dev); > > > bool host_addr = fdb_info->is_local; > > > struct dsa_switch *ds = dp->ds; > > > + u16 fdb_flags = 0; > > > > > > if (ctx && ctx != dp) > > > return 0; > > > @@ -3361,6 +3363,9 @@ static int dsa_slave_fdb_event(struct net_device *dev, > > > orig_dev->name, fdb_info->addr, fdb_info->vid, > > > host_addr ? " as host address" : ""); > > > > > > + if (fdb_info->locked) > > > + fdb_flags |= DSA_FDB_FLAG_LOCKED; > > > > This is the bridge->driver direction. In which of the changes up until > > now/through which mechanism will the bridge emit a > > SWITCHDEV_FDB_ADD_TO_DEVICE with fdb_info->locked = true? > > I believe it can happen in the following call chain: > > br_handle_frame_finish > br_fdb_update // p->flags & BR_PORT_MAB > fdb_notify > br_switchdev_fdb_notify > > This can happen with Spectrum when a packet ingresses via a locked port > and incurs an FDB miss in hardware. The packet will be trapped and > injected to the Rx path where it should invoke the above call chain.Ah, so this is the case which in mv88e6xxx would generate an ATU violation interrupt; in the Spectrum case it generates a special packet. Right now this packet isn't generated, right? I think we have the same thing in ocelot, a port can be configured to send "learn frames" to the CPU. Should these packets be injected into the bridge RX path in the first place? They reach the CPU because of an FDB miss, not because the CPU was the intended destination.