| Message ID | 20210320223448.2452869-1-olteanv@gmail.com |
|---|---|
| Headers | show |
| Series | Better support for sandwiched LAGs with bridge and DSA | expand |
On 21/03/2021 00:34, Vladimir Oltean wrote: > From: Vladimir Oltean <vladimir.oltean@nxp.com> > > The objective of this series is to make LAG uppers on top of switchdev > ports work regardless of which order we link interfaces to their masters > (first make the port join the LAG, then the LAG join the bridge, or the > other way around). > > There was a design decision to be made in patches 2-4 on whether we > should adopt the "push" model (which attempts to solve the problem > centrally, in the bridge layer) where the driver just calls: > > switchdev_bridge_port_offloaded(brport_dev, > &atomic_notifier_block, > &blocking_notifier_block, > extack); > > and the bridge just replays the entire collection of switchdev port > attributes and objects that it has, in some predefined order and with > some predefined error handling logic; > > > or the "pull" model (which attempts to solve the problem by giving the > driver the rope to hang itself), where the driver, apart from calling: > > switchdev_bridge_port_offloaded(brport_dev, extack); > > has the task of "dumpster diving" (as Tobias puts it) through the bridge > attributes and objects by itself, by calling: > > - br_vlan_replay > - br_fdb_replay > - br_mdb_replay > - br_vlan_enabled > - br_port_flag_is_set > - br_port_get_stp_state > - br_multicast_router > - br_get_ageing_time > > (not necessarily all of them, and not necessarily in this order, and > with driver-defined error handling). > > Even though I'm not in love myself with the "pull" model, I chose it > because there is a fundamental trick with replaying switchdev events > like this: > > ip link add br0 type bridge > ip link add bond0 type bond > ip link set bond0 master br0 > ip link set swp0 master bond0 <- this will replay the objects once for > the bond0 bridge port, and the swp0 > switchdev port will process them > ip link set swp1 master bond0 <- this will replay the objects again for > the bond0 bridge port, and the swp1 > switchdev port will see them, but swp0 > will see them for the second time now > > Basically I believe that it is implementation defined whether the driver > wants to error out on switchdev objects seen twice on a port, and the > bridge should not enforce a certain model for that. For example, for FDB > entries added to a bonding interface, the underling switchdev driver > might have an abstraction for just that: an FDB entry pointing towards a > logical (as opposed to physical) port. So when the second port joins the > bridge, it doesn't realy need to replay FDB entries, since there is > already at least one hardware port which has been receiving those > events, and the FDB entries don't need to be added a second time to the > same logical port. > In the other corner, we have the drivers that handle switchdev port > attributes on a LAG as individual switchdev port attributes on physical > ports (example: VLAN filtering). In fact, the switchdev_handle_port_attr_set > helper facilitates this: it is a fan-out from a single orig_dev towards > multiple lowers that pass the check_cb(). > But that's the point: switchdev_handle_port_attr_set is just a helper > which the driver _opts_ to use. The bridge can't enforce the "push" > model, because that would assume that all drivers handle port attributes > in the same way, which is probably false. > > For this reason, I preferred to go with the "pull" mode for this patch > set. Just to see how bad it is for other switchdev drivers to copy-paste > this logic, I added the pull support to ocelot too, and I think it's > pretty manageable. > > Vladimir Oltean (12): > net: dsa: call dsa_port_bridge_join when joining a LAG that is already > in a bridge > net: dsa: pass extack to dsa_port_{bridge,lag}_join > net: dsa: inherit the actual bridge port flags at join time > net: dsa: sync up with bridge port's STP state when joining > net: dsa: sync up VLAN filtering state when joining the bridge > net: dsa: sync multicast router state when joining the bridge > net: dsa: sync ageing time when joining the bridge > net: dsa: replay port and host-joined mdb entries when joining the > bridge > net: dsa: replay port and local fdb entries when joining the bridge > net: dsa: replay VLANs installed on port when joining the bridge > net: ocelot: call ocelot_netdevice_bridge_join when joining a bridged > LAG > net: ocelot: replay switchdev events when joining bridge > > drivers/net/dsa/ocelot/felix.c | 4 +- > drivers/net/ethernet/mscc/ocelot.c | 18 +-- > drivers/net/ethernet/mscc/ocelot_net.c | 208 +++++++++++++++++++++---- > include/linux/if_bridge.h | 40 +++++ > include/net/switchdev.h | 1 + > include/soc/mscc/ocelot.h | 6 +- > net/bridge/br_fdb.c | 52 +++++++ > net/bridge/br_mdb.c | 84 ++++++++++ > net/bridge/br_stp.c | 27 ++++ > net/bridge/br_vlan.c | 71 +++++++++ > net/dsa/dsa_priv.h | 9 +- > net/dsa/port.c | 203 ++++++++++++++++++------ > net/dsa/slave.c | 11 +- > 13 files changed, 631 insertions(+), 103 deletions(-) > Hi Vladimir, Please pull all of the new bridge code into separate patches with the proper bridge subsystems tagged in the subject. I'll review the bridge changes in a minute. Thanks, Nik
From: Vladimir Oltean <vladimir.oltean@nxp.com> The objective of this series is to make LAG uppers on top of switchdev ports work regardless of which order we link interfaces to their masters (first make the port join the LAG, then the LAG join the bridge, or the other way around). There was a design decision to be made in patches 2-4 on whether we should adopt the "push" model (which attempts to solve the problem centrally, in the bridge layer) where the driver just calls: switchdev_bridge_port_offloaded(brport_dev, &atomic_notifier_block, &blocking_notifier_block, extack); and the bridge just replays the entire collection of switchdev port attributes and objects that it has, in some predefined order and with some predefined error handling logic; or the "pull" model (which attempts to solve the problem by giving the driver the rope to hang itself), where the driver, apart from calling: switchdev_bridge_port_offloaded(brport_dev, extack); has the task of "dumpster diving" (as Tobias puts it) through the bridge attributes and objects by itself, by calling: - br_vlan_replay - br_fdb_replay - br_mdb_replay - br_vlan_enabled - br_port_flag_is_set - br_port_get_stp_state - br_multicast_router - br_get_ageing_time (not necessarily all of them, and not necessarily in this order, and with driver-defined error handling). Even though I'm not in love myself with the "pull" model, I chose it because there is a fundamental trick with replaying switchdev events like this: ip link add br0 type bridge ip link add bond0 type bond ip link set bond0 master br0 ip link set swp0 master bond0 <- this will replay the objects once for the bond0 bridge port, and the swp0 switchdev port will process them ip link set swp1 master bond0 <- this will replay the objects again for the bond0 bridge port, and the swp1 switchdev port will see them, but swp0 will see them for the second time now Basically I believe that it is implementation defined whether the driver wants to error out on switchdev objects seen twice on a port, and the bridge should not enforce a certain model for that. For example, for FDB entries added to a bonding interface, the underling switchdev driver might have an abstraction for just that: an FDB entry pointing towards a logical (as opposed to physical) port. So when the second port joins the bridge, it doesn't realy need to replay FDB entries, since there is already at least one hardware port which has been receiving those events, and the FDB entries don't need to be added a second time to the same logical port. In the other corner, we have the drivers that handle switchdev port attributes on a LAG as individual switchdev port attributes on physical ports (example: VLAN filtering). In fact, the switchdev_handle_port_attr_set helper facilitates this: it is a fan-out from a single orig_dev towards multiple lowers that pass the check_cb(). But that's the point: switchdev_handle_port_attr_set is just a helper which the driver _opts_ to use. The bridge can't enforce the "push" model, because that would assume that all drivers handle port attributes in the same way, which is probably false. For this reason, I preferred to go with the "pull" mode for this patch set. Just to see how bad it is for other switchdev drivers to copy-paste this logic, I added the pull support to ocelot too, and I think it's pretty manageable. Vladimir Oltean (12): net: dsa: call dsa_port_bridge_join when joining a LAG that is already in a bridge net: dsa: pass extack to dsa_port_{bridge,lag}_join net: dsa: inherit the actual bridge port flags at join time net: dsa: sync up with bridge port's STP state when joining net: dsa: sync up VLAN filtering state when joining the bridge net: dsa: sync multicast router state when joining the bridge net: dsa: sync ageing time when joining the bridge net: dsa: replay port and host-joined mdb entries when joining the bridge net: dsa: replay port and local fdb entries when joining the bridge net: dsa: replay VLANs installed on port when joining the bridge net: ocelot: call ocelot_netdevice_bridge_join when joining a bridged LAG net: ocelot: replay switchdev events when joining bridge drivers/net/dsa/ocelot/felix.c | 4 +- drivers/net/ethernet/mscc/ocelot.c | 18 +-- drivers/net/ethernet/mscc/ocelot_net.c | 208 +++++++++++++++++++++---- include/linux/if_bridge.h | 40 +++++ include/net/switchdev.h | 1 + include/soc/mscc/ocelot.h | 6 +- net/bridge/br_fdb.c | 52 +++++++ net/bridge/br_mdb.c | 84 ++++++++++ net/bridge/br_stp.c | 27 ++++ net/bridge/br_vlan.c | 71 +++++++++ net/dsa/dsa_priv.h | 9 +- net/dsa/port.c | 203 ++++++++++++++++++------ net/dsa/slave.c | 11 +- 13 files changed, 631 insertions(+), 103 deletions(-)