Revert "net: dsa: sja1105: Clear VLAN filtering offload netdev feature"

This reverts commit e9bf96943b408e6c99dd13fb01cb907335787c61.

The topic of the reverted patch is the support for switches with global
VLAN filtering, added by commit 061f6a505ac3 ("net: dsa: Add
ndo_vlan_rx_{add, kill}_vid implementation"). Be there a switch with 4
ports swp0 -> swp3, and the following setup:

ip link add br0 type bridge vlan_filtering 1
ip link set swp0 master br0
ip link set swp1 master br0

What would happen with VLAN-tagged traffic received on standalone ports
swp2 and swp3? Well, it would get dropped, were it not for the
.ndo_vlan_rx_add_vid and .ndo_vlan_rx_kill_vid implementations (called
from vlan_vid_add and vlan_vid_del respectively). Basically, for DSA
switches where VLAN filtering is a global attribute, we enforce the
standalone ports to have 'rx-vlan-filter: off [fixed]' in their ethtool
features, which lets the user know that all VLAN-tagged packets that are
not explicitly added in the RX filtering list are dropped.

As for the sja1105 driver, at the time of the reverted patch, it was
operating in a pretty handicapped mode when it had ports under a bridge
with vlan_filtering=1. Specifically, it was unable to terminate traffic
through the CPU port (for further explanation see "Traffic support" in
Documentation/networking/dsa/sja1105.rst).

However, since then, the sja1105 driver has made considerable progress,
and that limitation is no longer as severe now. Specifically, since
commit 2cafa72e516f ("net: dsa: sja1105: add a new
best_effort_vlan_filtering devlink parameter"), the driver is able to
perform CPU termination even when some ports are under bridges with
vlan_filtering=1. Then, since commit 8841f6e63f2c ("net: dsa: sja1105:
make devlink property best_effort_vlan_filtering true by default"), this
even became the default operating mode.

So we can now take advantage of the logic in the DSA core.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/dsa/sja1105/sja1105_main.c b/drivers/net/dsa/sja1105/sja1105_main.c
index 51ea104..d9c198c 100644 (file)
--- a/drivers/net/dsa/sja1105/sja1105_main.c
+++ b/drivers/net/dsa/sja1105/sja1105_main.c
@@ -3049,21 +3049,6 @@ static void sja1105_teardown(struct dsa_switch *ds)
        }
 }
 
-static int sja1105_port_enable(struct dsa_switch *ds, int port,
-                              struct phy_device *phy)
-{
-       struct net_device *slave;
-
-       if (!dsa_is_user_port(ds, port))
-               return 0;
-
-       slave = dsa_to_port(ds, port)->slave;
-
-       slave->features &= ~NETIF_F_HW_VLAN_CTAG_FILTER;
-
-       return 0;
-}
-
 static void sja1105_port_disable(struct dsa_switch *ds, int port)
 {
        struct sja1105_private *priv = ds->priv;
@@ -3491,7 +3476,6 @@ static const struct dsa_switch_ops sja1105_switch_ops = {
        .get_ethtool_stats      = sja1105_get_ethtool_stats,
        .get_sset_count         = sja1105_get_sset_count,
        .get_ts_info            = sja1105_get_ts_info,
-       .port_enable            = sja1105_port_enable,
        .port_disable           = sja1105_port_disable,
        .port_fdb_dump          = sja1105_fdb_dump,
        .port_fdb_add           = sja1105_fdb_add,