igb: Allow filters to be added for the local MAC address

Users expect that when adding a steering filter for the local MAC
address, that all the traffic directed to that address will go to some
queue.

Currently, it's not possible to configure entries in the "in use"
state, which is the normal state of the local MAC address entry (it is
the default), this patch allows to override the steering configuration
of "in use" entries, if the filter to be added match the address and
address type (source or destination) of an existing entry.

There is a bit of a special handling for entries referring to the
local MAC address, when they are removed, only the steering
configuration is reset.
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/igb/igb_main.c

@@ -6859,6 +6859,27 @@ static void igb_set_default_mac_filter(struct igb_adapter *adapter)
 	igb_rar_set_index(adapter, 0);
 }
 
+/* If the filter to be added and an already existing filter express
+ * the same address and address type, it should be possible to only
+ * override the other configurations, for example the queue to steer
+ * traffic.
+ */
+static bool igb_mac_entry_can_be_used(const struct igb_mac_addr *entry,
+				      const u8 *addr, const u8 flags)
+{
+	if (!(entry->state & IGB_MAC_STATE_IN_USE))
+		return true;
+
+	if ((entry->state & IGB_MAC_STATE_SRC_ADDR) !=
+	    (flags & IGB_MAC_STATE_SRC_ADDR))
+		return false;
+
+	if (!ether_addr_equal(addr, entry->addr))
+		return false;
+
+	return true;
+}
+
 /* Add a MAC filter for 'addr' directing matching traffic to 'queue',
  * 'flags' is used to indicate what kind of match is made, match is by
  * default for the destination address, if matching by source address
@@ -6881,7 +6902,8 @@ static int igb_add_mac_filter_flags(struct igb_adapter *adapter,
 	 * addresses.
 	 */
 	for (i = 0; i < rar_entries; i++) {
-		if (adapter->mac_table[i].state & IGB_MAC_STATE_IN_USE)
+		if (!igb_mac_entry_can_be_used(&adapter->mac_table[i],
+					       addr, flags))
 			continue;
 
 		ether_addr_copy(adapter->mac_table[i].addr, addr);
@@ -6933,9 +6955,19 @@ static int igb_del_mac_filter_flags(struct igb_adapter *adapter,
 		if (!ether_addr_equal(adapter->mac_table[i].addr, addr))
 			continue;
 
+		/* When a filter for the default address is "deleted",
+		 * we return it to its initial configuration
+		 */
+		if (adapter->mac_table[i].state & IGB_MAC_STATE_DEFAULT) {
+			adapter->mac_table[i].state =
+				IGB_MAC_STATE_DEFAULT | IGB_MAC_STATE_IN_USE;
+			adapter->mac_table[i].queue =
+				adapter->vfs_allocated_count;
+		} else {
 			adapter->mac_table[i].state = 0;
-		memset(adapter->mac_table[i].addr, 0, ETH_ALEN);
 			adapter->mac_table[i].queue = 0;
+			memset(adapter->mac_table[i].addr, 0, ETH_ALEN);
+		}
 
 		igb_rar_set_index(adapter, i);
 		return 0;