iavf: do not track VLAN 0 filters

When an interface with the maximum number of VLAN filters is brought up,
a spurious error is logged:

    [257.483082] 8021q: adding VLAN 0 to HW filter on device enp0s3
    [257.483094] iavf 0000:00:03.0 enp0s3: Max allowed VLAN filters 8. Remove existing VLANs or disable filtering via Ethtool if supported.

The VF driver complains that it cannot add the VLAN 0 filter.

On the other hand, the PF driver always adds VLAN 0 filter on VF
initialization. The VF does not need to ask the PF for that filter at
all.

Fix the error by not tracking VLAN 0 filters altogether. With that, the
check added by commit 0e710a3f ("iavf: Fix VF driver counting VLAN 0
filters") in iavf_virtchnl.c is useless and might be confusing if left as
it suggests that we track VLAN 0.

Fixes: 0e710a3f ("iavf: Fix VF driver counting VLAN 0 filters")
Signed-off-by: Ahmed Zaki <ahmed.zaki@intel.com>
Reviewed-by: Michal Kubiak <michal.kubiak@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/iavf/iavf_main.c

@@ -893,6 +893,10 @@ static int iavf_vlan_rx_add_vid(struct net_device *netdev,
 {
 	struct iavf_adapter *adapter = netdev_priv(netdev);
 
+	/* Do not track VLAN 0 filter, always added by the PF on VF init */
+	if (!vid)
+		return 0;
+
 	if (!VLAN_FILTERING_ALLOWED(adapter))
 		return -EIO;
 
@@ -919,6 +923,10 @@ static int iavf_vlan_rx_kill_vid(struct net_device *netdev,
 {
 	struct iavf_adapter *adapter = netdev_priv(netdev);
 
+	/* We do not track VLAN 0 filter */
+	if (!vid)
+		return 0;
+
 	iavf_del_vlan(adapter, IAVF_VLAN(vid, be16_to_cpu(proto)));
 	if (proto == cpu_to_be16(ETH_P_8021Q))
 		clear_bit(vid, adapter->vsi.active_cvlans);

drivers/net/ethernet/intel/iavf/iavf_virtchnl.c

@@ -2446,8 +2446,6 @@ void iavf_virtchnl_completion(struct iavf_adapter *adapter,
 		list_for_each_entry(f, &adapter->vlan_filter_list, list) {
 			if (f->is_new_vlan) {
 				f->is_new_vlan = false;
-				if (!f->vlan.vid)
-					continue;
 				if (f->vlan.tpid == ETH_P_8021Q)
 					set_bit(f->vlan.vid,
 						adapter->vsi.active_cvlans);