iavf: Fix TC config comparison with existing adapter TC config

Same number of TCs doesn't imply that underlying TC configs are
same. The config could be different due to difference in number
of queues in each TC. Add utility function to determine if TC
configs are same.

Fixes: d5b33d024496 ("i40evf: add ndo_setup_tc callback to i40evf")
Signed-off-by: Sudheer Mogilappagari <[e-mail]>
Tested-by: Mineri Bhange <[e-mail]> (A Contingent Worker at Intel)
Signed-off-by: Tony Nguyen <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

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

···
 }
 
 /**
+ * iavf_is_tc_config_same - Compare the mqprio TC config with the
+ * TC config already configured on this adapter.
+ * @adapter: board private structure
+ * @mqprio_qopt: TC config received from kernel.
+ *
+ * This function compares the TC config received from the kernel
+ * with the config already configured on the adapter.
+ *
+ * Return: True if configuration is same, false otherwise.
+ **/
+static bool iavf_is_tc_config_same(struct iavf_adapter *adapter,
+				   struct tc_mqprio_qopt *mqprio_qopt)
+{
+	struct virtchnl_channel_info *ch = &adapter->ch_config.ch_info[0];
+	int i;
+
+	if (adapter->num_tc != mqprio_qopt->num_tc)
+		return false;
+
+	for (i = 0; i < adapter->num_tc; i++) {
+		if (ch[i].count != mqprio_qopt->count[i] ||
+		    ch[i].offset != mqprio_qopt->offset[i])
+			return false;
+	}
+	return true;
+}
+
+/**
  * __iavf_setup_tc - configure multiple traffic classes
  * @netdev: network interface device structure
  * @type_data: tc offload data
···
 		if (ret)
 			return ret;
 		/* Return if same TC config is requested */
-		if (adapter->num_tc == num_tc)
+		if (iavf_is_tc_config_same(adapter, &mqprio_qopt->qopt))
 			return 0;
 		adapter->num_tc = num_tc;