[Bridge] [PATCH net] bridge: mdb: fix double add notification

[Cong Wang]

On Mon, Jul 13, 2015 at 6:36 AM, Nikolay Aleksandrov
<nikolay at cumulusnetworks.com> wrote:
> Since the mdb add/del code was introduced there have been 2 br_mdb_notify
> calls when doing br_mdb_add() resulting in 2 notifications on each add.
>
> Example:
>  Command: bridge mdb add dev br0 port eth1 grp 239.0.0.1 permanent
>  Before patch:
>  root at debian:~# bridge monitor all
>  [MDB]dev br0 port eth1 grp 239.0.0.1 permanent
>  [MDB]dev br0 port eth1 grp 239.0.0.1 permanent
>
>  After patch:
>  root at debian:~# bridge monitor all
>  [MDB]dev br0 port eth1 grp 239.0.0.1 permanent
>
> Signed-off-by: Nikolay Aleksandrov <nikolay at cumulusnetworks.com>
> Fixes: cfd567543590 ("bridge: add support of adding and deleting mdb entries")
> ---
>  net/bridge/br_mdb.c | 1 -
>  1 file changed, 1 deletion(-)
>
> diff --git a/net/bridge/br_mdb.c b/net/bridge/br_mdb.c
> index c11cf2611db0..1198a3dbad95 100644
> --- a/net/bridge/br_mdb.c
> +++ b/net/bridge/br_mdb.c
> @@ -351,7 +351,6 @@ static int br_mdb_add_group(struct net_bridge *br, struct net_bridge_port *port,
>         if (state == MDB_TEMPORARY)
>                 mod_timer(&p->timer, now + br->multicast_membership_interval);
>
> -       br_mdb_notify(br->dev, port, group, RTM_NEWMDB);
>         return 0;
>  }

Looks good to me.

And probably we can convert existing __br_mdb_notify() to using
non-atomic allocation too, but that is for net-next.