| Message ID | 20240214214005.4048469-1-tobias@waldekranz.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | net: bridge: switchdev: Ensure MDB events are delivered exactly once | expand |
Hello: This series was applied to netdev/net.git (main) by David S. Miller <davem@davemloft.net>: On Wed, 14 Feb 2024 22:40:02 +0100 you wrote: > When a device is attached to a bridge, drivers will request a replay > of objects that were created before the device joined the bridge, that > are still of interest to the joining port. Typical examples include > FDB entries and MDB memberships on other ports ("foreign interfaces") > or on the bridge itself. > > Conversely when a device is detached, the bridge will synthesize > deletion events for all those objects that are still live, but no > longer applicable to the device in question. > > [...] Here is the summary with links: - [v5,net,1/2] net: bridge: switchdev: Skip MDB replays of deferred events on offload https://git.kernel.org/netdev/net/c/dc489f86257c - [v5,net,2/2] net: bridge: switchdev: Ensure deferred event delivery on unoffload https://git.kernel.org/netdev/net/c/f7a70d650b0b You are awesome, thank you!
When a device is attached to a bridge, drivers will request a replay of objects that were created before the device joined the bridge, that are still of interest to the joining port. Typical examples include FDB entries and MDB memberships on other ports ("foreign interfaces") or on the bridge itself. Conversely when a device is detached, the bridge will synthesize deletion events for all those objects that are still live, but no longer applicable to the device in question. This series eliminates two races related to the synching and unsynching phases of a bridge's MDB with a joining or leaving device, that would cause notifications of such objects to be either delivered twice (1/2), or not at all (2/2). A similar race to the one solved by 1/2 still remains for the FDB. This is much harder to solve, due to the lockless operation of the FDB's rhashtable, and is therefore knowingly left out of this series. v1 -> v2: - Squash the previously separate addition of switchdev_port_obj_act_is_deferred into first consumer. - Use ether_addr_equal to compare MAC addresses. - Document switchdev_port_obj_act_is_deferred (renamed from switchdev_port_obj_is_deferred in v1, to indicate that we also match on the action). - Delay allocations of MDB objects until we know they're needed. - Use non-RCU version of the hash list iterator, now that the MDB is not scanned while holding the RCU read lock. - Add Fixes tag to commit message v2 -> v3: - Fix unlocking in error paths - Access RCU protected port list via mlock_dereference, since MDB is guaranteed to remain constant for the duration of the scan. v3 -> v4: - Limit the search for exiting deferred events in 1/2 to only apply to additions, since the problem does not exist in the deletion case. - Add 2/2, to plug a related race when unoffloading an indirectly associated device. v4 -> v5: - Fix grammatical errors in kerneldoc of switchdev_port_obj_act_is_deferred Tobias Waldekranz (2): net: bridge: switchdev: Skip MDB replays of deferred events on offload net: bridge: switchdev: Ensure deferred event delivery on unoffload include/net/switchdev.h | 3 ++ net/bridge/br_switchdev.c | 84 ++++++++++++++++++++++++++------------- net/switchdev/switchdev.c | 73 ++++++++++++++++++++++++++++++++++ 3 files changed, 132 insertions(+), 28 deletions(-)