+/* netif_setup_tc - Handle tc mappings on real_num_tx_queues change
+ * @dev: Network device
+ * @txq: number of queues available
+ *
+ * If real_num_tx_queues is changed the tc mappings may no longer be
+ * valid. To resolve this verify the tc mapping remains valid and if
+ * not NULL the mapping. With no priorities mapping to this
+ * offset/count pair it will no longer be used. In the worst case TC0
+ * is invalid nothing can be done so disable priority mappings. If is
+ * expected that drivers will fix this mapping if they can before
+ * calling netif_set_real_num_tx_queues.
+ */
+void netif_setup_tc(struct net_device *dev, unsigned int txq)
+{
+ int i;
+ struct netdev_tc_txq *tc = &dev->tc_to_txq[0];
+
+ /* If TC0 is invalidated disable TC mapping */
+ if (tc->offset + tc->count > txq) {
+ pr_warning("Number of in use tx queues changed "
+ "invalidating tc mappings. Priority "
+ "traffic classification disabled!\n");
+ dev->num_tc = 0;
+ return;
+ }
+
+ /* Invalidated prio to tc mappings set to TC0 */
+ for (i = 1; i < TC_BITMASK + 1; i++) {
+ int q = netdev_get_prio_tc_map(dev, i);
+
+ tc = &dev->tc_to_txq[q];
+ if (tc->offset + tc->count > txq) {
+ pr_warning("Number of in use tx queues "
+ "changed. Priority %i to tc "
+ "mapping %i is no longer valid "
+ "setting map to 0\n",
+ i, q);
+ netdev_set_prio_tc_map(dev, i, 0);
+ }
+ }
+}
+