net: bridge: disable bridge MTU auto tuning if it was set manually
As Roopa noted today the biggest source of problems when configuring
bridge and ports is that the bridge MTU keeps changing automatically on
port events (add/del/changemtu). That leads to inconsistent behaviour
and network config software needs to chase the MTU and fix it on each
such event. Let's improve on that situation and allow for the user to
set any MTU within ETH_MIN/MAX limits, but once manually configured it
is the user's responsibility to keep it correct afterwards.
In case the MTU isn't manually set - the behaviour reverts to the
previous and the bridge follows the minimum MTU.
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 586f84b..a7cb3ec 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -410,6 +410,7 @@ struct net_bridge {
int offload_fwd_mark;
#endif
bool neigh_suppress_enabled;
+ bool mtu_set_by_user;
struct hlist_head fdb_list;
};
@@ -578,7 +579,7 @@ int br_del_bridge(struct net *net, const char *name);
int br_add_if(struct net_bridge *br, struct net_device *dev,
struct netlink_ext_ack *extack);
int br_del_if(struct net_bridge *br, struct net_device *dev);
-int br_mtu(const struct net_bridge *br, bool max);
+void br_mtu_auto_adjust(struct net_bridge *br);
netdev_features_t br_features_recompute(struct net_bridge *br,
netdev_features_t features);
void br_port_flags_change(struct net_bridge_port *port, unsigned long mask);