diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c index ae5762af0146763215b500b3ecbb4590a3901f88..24c9c0c3f3166f66d5696175fe8dd55f1fdce8c7 100644 --- a/net/batman-adv/hard-interface.c +++ b/net/batman-adv/hard-interface.c @@ -630,7 +630,19 @@ int batadv_hardif_min_mtu(struct net_device *soft_iface) */ void batadv_update_min_mtu(struct net_device *soft_iface) { - dev_set_mtu(soft_iface, batadv_hardif_min_mtu(soft_iface)); + struct batadv_priv *bat_priv = netdev_priv(soft_iface); + int limit_mtu; + int mtu; + + mtu = batadv_hardif_min_mtu(soft_iface); + + if (bat_priv->mtu_set_by_user) + limit_mtu = bat_priv->mtu_set_by_user; + else + limit_mtu = ETH_DATA_LEN; + + mtu = min(mtu, limit_mtu); + dev_set_mtu(soft_iface, mtu); /* Check if the local translate table should be cleaned up to match a * new (and smaller) MTU. diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c index 0f5c0679b55a296603282aa5c7047d7dc6c95234..38d411a52f3315232bb16fe6c6445fa0abc92e41 100644 --- a/net/batman-adv/soft-interface.c +++ b/net/batman-adv/soft-interface.c @@ -154,11 +154,14 @@ static int batadv_interface_set_mac_addr(struct net_device *dev, void *p) static int batadv_interface_change_mtu(struct net_device *dev, int new_mtu) { + struct batadv_priv *bat_priv = netdev_priv(dev); + /* check ranges */ if (new_mtu < 68 || new_mtu > batadv_hardif_min_mtu(dev)) return -EINVAL; dev->mtu = new_mtu; + bat_priv->mtu_set_by_user = new_mtu; return 0; } diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h index 758cd797a063b565ef1d2512793020db90374624..76791815b26ba46540d32a2053ed61c5cc7757d6 100644 --- a/net/batman-adv/types.h +++ b/net/batman-adv/types.h @@ -1546,6 +1546,12 @@ struct batadv_priv { /** @soft_iface: net device which holds this struct as private data */ struct net_device *soft_iface; + /** + * @mtu_set_by_user: MTU was set once by user + * protected by rtnl_lock + */ + int mtu_set_by_user; + /** * @bat_counters: mesh internal traffic statistic counters (see * batadv_counters)