The following commit has been merged in the master branch: commit 8c46fcd783082118e72ebbe1937b93bb7df8a63c Author: Marek Lindner mareklindner@neomailbox.ch Date: Mon May 14 06:38:49 2018 +0800

batman-adv: disable ethtool link speed detection when auto negotiation off

Virtual interface drivers such as tun / tap interfaces, VLAN, etc tend to initialize the interface throughput with some value for the sake of having a throughput number to export via ethtool. This exported throughput leaves batman-adv to conclude the interface throughput is genuine (reflecting reality), thus no measurements are necessary.

Based on the observation that those interface types also tend to set the link auto-negotiation to 'off', batman-adv shall check this setting to differentiate between genuine link throughput information and placeholders installed by virtual interfaces.

The "default throughput" setting exported via sysfs still allows to configure the batman-adv throughput for the interface, thus disabling the measurements.

Signed-off-by: Marek Lindner mareklindner@neomailbox.ch Acked-by: Antonio Quartulli a@unstable.cc Signed-off-by: Sven Eckelmann sven@narfation.org Signed-off-by: Simon Wunderlich sw@simonwunderlich.de

diff --git a/net/batman-adv/bat_v_elp.c b/net/batman-adv/bat_v_elp.c index 28687493599f..71c20c1d4002 100644 --- a/net/batman-adv/bat_v_elp.c +++ b/net/batman-adv/bat_v_elp.c @@ -127,7 +127,20 @@ static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh) rtnl_lock(); ret = __ethtool_get_link_ksettings(hard_iface->net_dev, &link_settings); rtnl_unlock(); - if (ret == 0) { + + /* Virtual interface drivers such as tun / tap interfaces, VLAN, etc + * tend to initialize the interface throughput with some value for the + * sake of having a throughput number to export via ethtool. This + * exported throughput leaves batman-adv to conclude the interface + * throughput is genuine (reflecting reality), thus no measurements + * are necessary. + * + * Based on the observation that those interface types also tend to set + * the link auto-negotiation to 'off', batman-adv shall check this + * setting to differentiate between genuine link throughput information + * and placeholders installed by virtual interfaces. + */ + if (ret == 0 && link_settings.base.autoneg == AUTONEG_ENABLE) { /* link characteristics might change over time */ if (link_settings.base.duplex == DUPLEX_FULL) hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;