Re: [PATCH net-next] bridge: Let bridge not age 'externally' learnt FDB entries, they are removed when 'external' entity notifies the aging

On 2/4/15, 12:02 AM, Siva Mannem wrote:

On Tue, Feb 3, 2015 at 8:41 PM, roopa [off-list ref] wrote:

quoted

On 2/2/15, 9:21 AM, Siva Mannem wrote:

quoted

   When 'learned_sync' flag is turned on, the offloaded switch
   port syncs learned MAC addresses to bridge's FDB via switchdev notifier
   (NETDEV_SWITCH_FDB_ADD). Currently, FDB entries learnt via this
mechanism are
   wrongly being deleted by bridge aging logic. This patch ensures that FDB
   entries synced from offloaded switch ports are not deleted by bridging
logic.
   Such entries can only be deleted via switchdev notifier
   (NETDEV_SWITCH_FDB_DEL).

Your patch seems right and maintains symmetry for fdb add/del of externally
learnt entries.
However, this could be made configurable. I think some drivers may rely on
bridge driver aging these entries (The default setting needs more thought).
I am not sure what rocker does (CC'ed rocker maintainers). But, our driver
does rely on the bridge driver aging these entries by default.

added_by_external_learn flag is only set for entries learned via
switchdev notifier
(NETDEV_SWITCH_FDB_ADD) and rocker is the only driver using these notifiers.
  I see that rocker is deleting the entries via switchdev notifier
(NETDEV_SWITCH_FDB_DEL).
This mechanism is only used by drivers when learned_sync is turned on by user.

$ sudo bridge link set dev swp1 learning_sync on self

Am I missing something here?

I know that its enabled by an external flag. I wasn't sure rocker was doing a del
or was relying on the bridge driver to age those entries (hence the CC to rocker maintainers).
And, my only point was its valid in some cases for the switch driver to rely on bridge driver ageing those entries.
For symmetry, your patch seems right.