From: Sven Eckelmann sven@narfation.org

[ Upstream commit 9ad346c90509ebd983f60da7d082f261ad329507 ]

The commit 8c46fcd78308 ("batman-adv: disable ethtool link speed detection when auto negotiation off") disabled the usage of ethtool's link_ksetting when auto negotation was enabled due to invalid values when used with tun/tap virtual net_devices. According to the patch, automatic measurements should be used for these kind of interfaces.

But there are major flaws with this argumentation:

* automatic measurements are not implemented * auto negotiation has nothing to do with the validity of the retrieved values

The first point has to be fixed by a longer patch series. The "validity" part of the second point must be addressed in the same patch series by dropping the usage of ethtool's link_ksetting (thus always doing automatic measurements over ethernet).

Drop the patch again to have more default values for various net_device types/configurations. The user can still overwrite them using the batadv_hardif's BATADV_ATTR_THROUGHPUT_OVERRIDE.

Reported-by: Matthias Schiffer mschiffer@universe-factory.net Signed-off-by: Sven Eckelmann sven@narfation.org Signed-off-by: Simon Wunderlich sw@simonwunderlich.de Signed-off-by: Sasha Levin sashal@kernel.org --- net/batman-adv/bat_v_elp.c | 15 +-------------- 1 file changed, 1 insertion(+), 14 deletions(-)

diff --git a/net/batman-adv/bat_v_elp.c b/net/batman-adv/bat_v_elp.c index 1e3172db7492..955e0b8960d6 100644 --- a/net/batman-adv/bat_v_elp.c +++ b/net/batman-adv/bat_v_elp.c @@ -127,20 +127,7 @@ 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(); - - /* 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) { + if (ret == 0) { /* link characteristics might change over time */ if (link_settings.base.duplex == DUPLEX_FULL) hard_iface->bat_v.flags |= BATADV_FULL_DUPLEX;