igb: change queue ordering for 82576 based adapters

This patch changes the queue ordering for 82576 adapters so that if VFs are
enabled the queues will first be allocated out of the PF pool.  Any
remaining queues will be allocated out of other VMDq pools.
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/igb/igb_main.c

@@ -285,7 +285,7 @@ module_exit(igb_exit_module);
  **/
 static void igb_cache_ring_register(struct igb_adapter *adapter)
 {
-	int i;
+	int i = 0, j = 0;
 	u32 rbase_offset = adapter->vfs_allocated_count;
 
 	switch (adapter->hw.mac.type) {
@@ -295,19 +295,20 @@ static void igb_cache_ring_register(struct igb_adapter *adapter)
 		 * In order to avoid collision we start at the first free queue
 		 * and continue consuming queues in the same sequence
 		 */
-		for (i = 0; i < adapter->num_rx_queues; i++)
+		if (adapter->vfs_allocated_count) {
+			for (; i < adapter->num_rx_queues; i++)
 				adapter->rx_ring[i].reg_idx = rbase_offset +
 				                              Q_IDX_82576(i);
-		for (i = 0; i < adapter->num_tx_queues; i++)
-			adapter->tx_ring[i].reg_idx = rbase_offset +
-			                              Q_IDX_82576(i);
-		break;
+			for (; j < adapter->num_tx_queues; j++)
+				adapter->tx_ring[j].reg_idx = rbase_offset +
+				                              Q_IDX_82576(j);
+		}
 	case e1000_82575:
 	default:
-		for (i = 0; i < adapter->num_rx_queues; i++)
-			adapter->rx_ring[i].reg_idx = i;
-		for (i = 0; i < adapter->num_tx_queues; i++)
-			adapter->tx_ring[i].reg_idx = i;
+		for (; i < adapter->num_rx_queues; i++)
+			adapter->rx_ring[i].reg_idx = rbase_offset + i;
+		for (; j < adapter->num_tx_queues; j++)
+			adapter->tx_ring[j].reg_idx = rbase_offset + j;
 		break;
 	}
 }