On Fri, Feb 11, 2022 at 03:14:26PM +0200, Oleksandr Mazur wrote:
> Whenever bridge driver hits the max capacity of MDBs, it disables
> the MC processing (by setting corresponding bridge option), but never
> notifies switchdev about such change (the notifiers are called only upon
> explicit setting of this option, through the registered netlink interface).
>
> This could lead to situation when Software MDB processing gets disabled,
> but this event never gets offloaded to the underlying Hardware.
>
> Fix this by adding a notify message in such case.
>
> Signed-off-by: Oleksandr Mazur <oleksandr.mazur@xxxxxxxxxxx>
> ---
> net/bridge/br_multicast.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
> index de2409889489..d53c08906bc8 100644
> --- a/net/bridge/br_multicast.c
> +++ b/net/bridge/br_multicast.c
> @@ -82,6 +82,9 @@ static void br_multicast_find_del_pg(struct net_bridge *br,
> struct net_bridge_port_group *pg);
> static void __br_multicast_stop(struct net_bridge_mcast *brmctx);
>
> +static int br_mc_disabled_update(struct net_device *dev, bool value,
> + struct netlink_ext_ack *extack);
> +
> static struct net_bridge_port_group *
> br_sg_port_find(struct net_bridge *br,
> struct net_bridge_port_group_sg_key *sg_p)
> @@ -1156,6 +1159,8 @@ struct net_bridge_mdb_entry *br_multicast_new_group(struct net_bridge *br,
> return mp;
>
> if (atomic_read(&br->mdb_hash_tbl.nelems) >= br->hash_max) {
> + err = br_mc_disabled_update(br->dev, false, NULL);
> + WARN_ON(err && err != -EOPNOTSUPP);
What is the purpose of the WARN_ON()? There are a lot of operations that
can fail in rollback paths, but we never WARN_ON() there
I suggest:
br_mc_disabled_update(br->dev, false, NULL);
> br_opt_toggle(br, BROPT_MULTICAST_ENABLED, false);
> return ERR_PTR(-E2BIG);
> }
> --
> 2.17.1
>
