sfc: VLAN filters must only be created if the firmware supports this.

If it is not supported we simply disable the feature.

For the feature to work we need firmware filter support for
OUTER_VID + LOC_MAC and for OUTER_VID + LOC_MAC_IG.
The low-latency firmware can match on OUTER_VID + LOC_MAC but not on
OUTER_VID + LOC_MAC_IG.
For the capture packet firmware it is the other way around.
Only the full-feature variant can match on both combinations.

Incorporates a fix by Andrew Rybchenko <Andrew.Rybchenko@oktetlabs.ru>
in the net_dev->[hw_]features handling.
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/sfc/ef10.c

@@ -3977,6 +3977,7 @@ static int efx_ef10_filter_table_probe(struct efx_nic *efx)
 	MCDI_DECLARE_BUF(inbuf, MC_CMD_GET_PARSER_DISP_INFO_IN_LEN);
 	MCDI_DECLARE_BUF(outbuf, MC_CMD_GET_PARSER_DISP_INFO_OUT_LENMAX);
 	struct efx_ef10_nic_data *nic_data = efx->nic_data;
+	struct net_device *net_dev = efx->net_dev;
 	unsigned int pd_match_pri, pd_match_count;
 	struct efx_ef10_filter_table *table;
 	struct efx_ef10_vlan *vlan;
@@ -4026,6 +4027,18 @@ static int efx_ef10_filter_table_probe(struct efx_nic *efx)
 		}
 	}
 
+	if ((efx_supported_features(efx) & NETIF_F_HW_VLAN_CTAG_FILTER) &&
+	    !(efx_ef10_filter_match_supported(table,
+		(EFX_FILTER_MATCH_OUTER_VID | EFX_FILTER_MATCH_LOC_MAC)) &&
+	      efx_ef10_filter_match_supported(table,
+		(EFX_FILTER_MATCH_OUTER_VID | EFX_FILTER_MATCH_LOC_MAC_IG)))) {
+		netif_info(efx, probe, net_dev,
+			   "VLAN filters are not supported in this firmware variant\n");
+		net_dev->features &= ~NETIF_F_HW_VLAN_CTAG_FILTER;
+		efx->fixed_features &= ~NETIF_F_HW_VLAN_CTAG_FILTER;
+		net_dev->hw_features &= ~NETIF_F_HW_VLAN_CTAG_FILTER;
+	}
+
 	table->entry = vzalloc(HUNT_FILTER_TBL_ROWS * sizeof(*table->entry));
 	if (!table->entry) {
 		rc = -ENOMEM;

drivers/net/ethernet/sfc/net_driver.h

@@ -1524,4 +1524,16 @@ static inline void efx_xmit_hwtstamp_pending(struct sk_buff *skb)
 	skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
 }
 
+/* Get all supported features.
+ * If a feature is not fixed, it is present in hw_features.
+ * If a feature is fixed, it does not present in hw_features, but
+ * always in features.
+ */
+static inline netdev_features_t efx_supported_features(const struct efx_nic *efx)
+{
+	const struct net_device *net_dev = efx->net_dev;
+
+	return net_dev->features | net_dev->hw_features;
+}
+
 #endif /* EFX_NET_DRIVER_H */