user/sven/linux.git/include/net/switchdev.h, branch v6.1.4

net: switchdev: add reminder near struct switchdev_notifier_fdb_info

2022-06-30T03:37:36Z

br_switchdev_fdb_notify() creates an on-stack FDB info variable, and initializes it member by member. As such, newly added fields which are not initialized by br_switchdev_fdb_notify() will contain junk bytes from the stack. Other uses of struct switchdev_notifier_fdb_info have a struct initializer which should put zeroes in the uninitialized fields. Add a reminder above the structure for future developers. Recently discussed during review. Link: https://patchwork.kernel.org/project/netdevbpf/patch/20220524152144.40527-2-schultz.hans+netdev@gmail.com/#24877698 Link: https://patchwork.kernel.org/project/netdevbpf/patch/20220524152144.40527-3-schultz.hans+netdev@gmail.com/#24912269 Signed-off-by: Vladimir Oltean Reviewed-by: Ido Schimmel Reviewed-by: Nikolay Aleksandrov Link: https://lore.kernel.org/r/20220628100831.2899434-1-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski

net: bridge: mst: Notify switchdev drivers of MST state changes

2022-03-17T23:49:58Z

Generate a switchdev notification whenever an MST state changes. This notification is keyed by the VLANs MSTI rather than the VID, since multiple VLANs may share the same MST instance. Signed-off-by: Tobias Waldekranz Acked-by: Nikolay Aleksandrov Signed-off-by: Jakub Kicinski

net: bridge: mst: Notify switchdev drivers of VLAN MSTI migrations

2022-03-17T23:49:58Z

Whenever a VLAN moves to a new MSTI, send a switchdev notification so that switchdevs can track a bridge's VID to MSTI mappings. Signed-off-by: Tobias Waldekranz Acked-by: Nikolay Aleksandrov Signed-off-by: Jakub Kicinski

net: bridge: mst: Notify switchdev drivers of MST mode changes

2022-03-17T23:49:57Z

Trigger a switchdev event whenever the bridge's MST mode is enabled/disabled. This allows constituent ports to either perform any required hardware config, or refuse the change if it not supported. Signed-off-by: Tobias Waldekranz Acked-by: Nikolay Aleksandrov Signed-off-by: Jakub Kicinski

net: switchdev: remove lag_mod_cb from switchdev_handle_fdb_event_to_device

2022-02-25T05:31:43Z

When the switchdev_handle_fdb_event_to_device() event replication helper was created, my original thought was that FDB events on LAG interfaces should most likely be special-cased, not just replicated towards all switchdev ports beneath that LAG. So this replication helper currently does not recurse through switchdev lower interfaces of LAG bridge ports, but rather calls the lag_mod_cb() if that was provided. No switchdev driver uses this helper for FDB events on LAG interfaces yet, so that was an assumption which was yet to be tested. It is certainly usable for that purpose, as my RFC series shows: https://patchwork.kernel.org/project/netdevbpf/cover/20220210125201.2859463-1-vladimir.oltean@nxp.com/ however this approach is slightly convoluted because: - the switchdev driver gets a "dev" that isn't its own net device, but rather the LAG net device. It must call switchdev_lower_dev_find(dev) in order to get a handle of any of its own net devices (the ones that pass check_cb). - in order for FDB entries on LAG ports to be correctly refcounted per the number of switchdev ports beneath that LAG, we haven't escaped the need to iterate through the LAG's lower interfaces. Except that is now the responsibility of the switchdev driver, because the replication helper just stopped half-way. So, even though yes, FDB events on LAG bridge ports must be special-cased, in the end it's simpler to let switchdev_handle_fdb_* just iterate through the LAG port's switchdev lowers, and let the switchdev driver figure out that those physical ports are under a LAG. The switchdev_handle_fdb_event_to_device() helper takes a "foreign_dev_check" callback so it can figure out whether @dev can autonomously forward to @foreign_dev. DSA fills this method properly: if the LAG is offloaded by another port in the same tree as @dev, then it isn't foreign. If it is a software LAG, it is foreign - forwarding happens in software. Whether an interface is foreign or not decides whether the replication helper will go through the LAG's switchdev lowers or not. Since the lan966x doesn't properly fill this out, FDB events on software LAG uppers will get called. By changing lan966x_foreign_dev_check(), we can suppress them. Whereas DSA will now start receiving FDB events for its offloaded LAG uppers, so we need to return -EOPNOTSUPP, since we currently don't do the right thing for them. Cc: Horatiu Vultur Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: Jakub Kicinski

net: switchdev: introduce switchdev_handle_port_obj_{add,del} for foreign interfaces

2022-02-16T11:21:04Z

The switchdev_handle_port_obj_add() helper is good for replicating a port object on the lower interfaces of @dev, if that object was emitted on a bridge, or on a bridge port that is a LAG. However, drivers that use this helper limit themselves to a box from which they can no longer intercept port objects notified on neighbor ports ("foreign interfaces"). One such driver is DSA, where software bridging with foreign interfaces such as standalone NICs or Wi-Fi APs is an important use case. There, a VLAN installed on a neighbor bridge port roughly corresponds to a forwarding VLAN installed on the DSA switch's CPU port. To support this use case while also making use of the benefits of the switchdev_handle_* replication helper for port objects, introduce a new variant of these functions that crawls through the neighbor ports of @dev, in search of potentially compatible switchdev ports that are interested in the event. The strategy is identical to switchdev_handle_fdb_event_to_device(): if @dev wasn't a switchdev interface, then go one step upper, and recursively call this function on the bridge that this port belongs to. At the next recursion step, __switchdev_handle_port_obj_add() will iterate through the bridge's lower interfaces. Among those, some will be switchdev interfaces, and one will be the original @dev that we came from. To prevent infinite recursion, we must suppress reentry into the original @dev, and just call the @add_cb for the switchdev_interfaces. It looks like this: br0 / | \ / | \ / | \ swp0 swp1 eth0 1. __switchdev_handle_port_obj_add(eth0) -> check_cb(eth0) returns false -> eth0 has no lower interfaces -> eth0's bridge is br0 -> switchdev_lower_dev_find(br0, check_cb, foreign_dev_check_cb)) finds br0 2. __switchdev_handle_port_obj_add(br0) -> check_cb(br0) returns false -> netdev_for_each_lower_dev -> check_cb(swp0) returns true, so we don't skip this interface 3. __switchdev_handle_port_obj_add(swp0) -> check_cb(swp0) returns true, so we call add_cb(swp0) (back to netdev_for_each_lower_dev from 2) -> check_cb(swp1) returns true, so we don't skip this interface 4. __switchdev_handle_port_obj_add(swp1) -> check_cb(swp1) returns true, so we call add_cb(swp1) (back to netdev_for_each_lower_dev from 2) -> check_cb(eth0) returns false, so we skip this interface to avoid infinite recursion Note: eth0 could have been a LAG, and we don't want to suppress the recursion through its lowers if those exist, so when check_cb() returns false, we still call switchdev_lower_dev_find() to estimate whether there's anything worth a recursion beneath that LAG. Using check_cb() and foreign_dev_check_cb(), switchdev_lower_dev_find() not only figures out whether the lowers of the LAG are switchdev, but also whether they actively offload the LAG or not (whether the LAG is "foreign" to the switchdev interface or not). The port_obj_info->orig_dev is preserved across recursive calls, so switchdev drivers still know on which device was this notification originally emitted. Signed-off-by: Vladimir Oltean Signed-off-by: David S. Miller

net: bridge: switchdev: differentiate new VLANs from changed ones

2022-02-16T11:21:04Z

br_switchdev_port_vlan_add() currently emits a SWITCHDEV_PORT_OBJ_ADD event with a SWITCHDEV_OBJ_ID_PORT_VLAN for 2 distinct cases: - a struct net_bridge_vlan got created - an existing struct net_bridge_vlan was modified This makes it impossible for switchdev drivers to properly balance PORT_OBJ_ADD with PORT_OBJ_DEL events, so if we want to allow that to happen, we must provide a way for drivers to distinguish between a VLAN with changed flags and a new one. Annotate struct switchdev_obj_port_vlan with a "bool changed" that distinguishes the 2 cases above. Signed-off-by: Vladimir Oltean Signed-off-by: David S. Miller

net: switchdev: merge switchdev_handle_fdb_{add,del}_to_device

2021-10-27T13:54:02Z

To reduce code churn, the same patch makes multiple changes, since they all touch the same lines: 1. The implementations for these two are identical, just with different function pointers. Reduce duplications and name the function pointers "mod_cb" instead of "add_cb" and "del_cb". Pass the event as argument. 2. Drop the "const" attribute from "orig_dev". If the driver needs to check whether orig_dev belongs to itself and then call_switchdev_notifiers(orig_dev, SWITCHDEV_FDB_OFFLOADED), it can't, because call_switchdev_notifiers takes a non-const struct net_device *. Signed-off-by: Vladimir Oltean Reviewed-by: Ido Schimmel Signed-off-by: David S. Miller

net: make switchdev_bridge_port_{,unoffload} loosely coupled with the bridge

2021-08-04T11:35:07Z

With the introduction of explicit offloading API in switchdev in commit 2f5dc00f7a3e ("net: bridge: switchdev: let drivers inform which bridge ports are offloaded"), we started having Ethernet switch drivers calling directly into a function exported by net/bridge/br_switchdev.c, which is a function exported by the bridge driver. This means that drivers that did not have an explicit dependency on the bridge before, like cpsw and am65-cpsw, now do - otherwise it is not possible to call a symbol exported by a driver that can be built as module unless you are a module too. There was an attempt to solve the dependency issue in the form of commit b0e81817629a ("net: build all switchdev drivers as modules when the bridge is a module"). Grygorii Strashko, however, says about it: | In my opinion, the problem is a bit bigger here than just fixing the | build :( | | In case, of ^cpsw the switchdev mode is kinda optional and in many | cases (especially for testing purposes, NFS) the multi-mac mode is | still preferable mode. | | There were no such tight dependency between switchdev drivers and | bridge core before and switchdev serviced as independent, notification | based layer between them, so ^cpsw still can be "Y" and bridge can be | "M". Now for mostly every kernel build configuration the CONFIG_BRIDGE | will need to be set as "Y", or we will have to update drivers to | support build with BRIDGE=n and maintain separate builds for | networking vs non-networking testing. But is this enough? Wouldn't | it cause 'chain reaction' required to add more and more "Y" options | (like CONFIG_VLAN_8021Q)? | | PS. Just to be sure we on the same page - ARM builds will be forced | (with this patch) to have CONFIG_TI_CPSW_SWITCHDEV=m and so all our | automation testing will just fail with omap2plus_defconfig. In the light of this, it would be desirable for some configurations to avoid dependencies between switchdev drivers and the bridge, and have the switchdev mode as completely optional within the driver. Arnd Bergmann also tried to write a patch which better expressed the build time dependency for Ethernet switch drivers where the switchdev support is optional, like cpsw/am65-cpsw, and this made the drivers follow the bridge (compile as module if the bridge is a module) only if the optional switchdev support in the driver was enabled in the first place: https://patchwork.kernel.org/project/netdevbpf/patch/20210802144813.1152762-1-arnd@kernel.org/ but this still did not solve the fact that cpsw and am65-cpsw now must be built as modules when the bridge is a module - it just expressed correctly that optional dependency. But the new behavior is an apparent regression from Grygorii's perspective. So to support the use case where the Ethernet driver is built-in, NET_SWITCHDEV (a bool option) is enabled, and the bridge is a module, we need a framework that can handle the possible absence of the bridge from the running system, i.e. runtime bloatware as opposed to build-time bloatware. Luckily we already have this framework, since switchdev has been using it extensively. Events from the bridge side are transmitted to the driver side using notifier chains - this was originally done so that unrelated drivers could snoop for events emitted by the bridge towards ports that are implemented by other drivers (think of a switch driver with LAG offload that listens for switchdev events on a bonding/team interface that it offloads). There are also events which are transmitted from the driver side to the bridge side, which again are modeled using notifiers. SWITCHDEV_FDB_ADD_TO_BRIDGE is an example of this, and deals with notifying the bridge that a MAC address has been dynamically learned. So there is a precedent we can use for modeling the new framework. The difference compared to SWITCHDEV_FDB_ADD_TO_BRIDGE is that the work that the bridge needs to do when a port becomes offloaded is blocking in its nature: replay VLANs, MDBs etc. The calling context is indeed blocking (we are under rtnl_mutex), but the existing switchdev notification chain that the bridge is subscribed to is only the atomic one. So we need to subscribe the bridge to the blocking switchdev notification chain too. This patch: - keeps the driver-side perception of the switchdev_bridge_port_{,un}offload unchanged - moves the implementation of switchdev_bridge_port_{,un}offload from the bridge module into the switchdev module. - makes everybody that is subscribed to the switchdev blocking notifier chain "hear" offload & unoffload events - makes the bridge driver subscribe and handle those events - moves the bridge driver's handling of those events into 2 new functions called br_switchdev_port_{,un}offload. These functions contain in fact the core of the logic that was previously in switchdev_bridge_port_{,un}offload, just that now we go through an extra indirection layer to reach them. Unlike all the other switchdev notification structures, the structure used to carry the bridge port information, struct switchdev_notifier_brport_info, does not contain a "bool handled". This is because in the current usage pattern, we always know that a switchdev bridge port offloading event will be handled by the bridge, because the switchdev_bridge_port_offload() call was initiated by a NETDEV_CHANGEUPPER event in the first place, where info->upper_dev is a bridge. So if the bridge wasn't loaded, then the CHANGEUPPER event couldn't have happened. Signed-off-by: Vladimir Oltean Tested-by: Grygorii Strashko Signed-off-by: David S. Miller

net: switchdev: remove stray semicolon in switchdev_handle_fdb_del_to_device shim

2021-07-21T15:00:16Z

With the semicolon at the end, the compiler sees the shim function as a declaration and not as a definition, and warns: 'switchdev_handle_fdb_del_to_device' declared 'static' but never defined Reported-by: kernel test robot Fixes: 8ca07176ab00 ("net: switchdev: introduce a fanout helper for SWITCHDEV_FDB_{ADD,DEL}_TO_DEVICE") Signed-off-by: Vladimir Oltean Tested-by: Matthieu Baerts Signed-off-by: David S. Miller