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

From: roopa <[email-masked]>
Date: Tue, 03 Feb 2015 07:11:29 -0800

On 2/2/15, 9:21 AM, Siva Mannem wrote:
>   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.
>
> Signed-off-by: Siva Mannem <[email-masked]>
> ---
>   net/bridge/br_fdb.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
> index 08bf04b..6eb94b5 100644
> --- a/net/bridge/br_fdb.c
> +++ b/net/bridge/br_fdb.c
> @@ -280,7 +280,7 @@ void br_fdb_cleanup(unsigned long _data)
>   
>   		hlist_for_each_entry_safe(f, n, &br->hash[i], hlist) {
>   			unsigned long this_timer;
> -			if (f->is_static)
> +			if (f->is_static || f->added_by_external_learn)
>   				continue;
>   			this_timer = f->updated + delay;
>   			if (time_before_eq(this_timer, jiffies))