ixgbe: add clean rx many routine

in some configurations there can be more than one rx queue per vector
in msi-x mode.  Add functionality to be able to clean this without
changing the performance path single-rx-queue cleanup.

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/net/ixgbe/ixgbe_main.c

@@ -1024,13 +1024,15 @@ static irqreturn_t ixgbe_msix_clean_many(int irq, void *data)
  * @napi: napi struct with our devices info in it
  * @budget: amount of work driver is allowed to do this pass, in packets
  *
+ * This function is optimized for cleaning one queue only on a single
+ * q_vector!!!
  **/
 static int ixgbe_clean_rxonly(struct napi_struct *napi, int budget)
 {
 	struct ixgbe_q_vector *q_vector =
 			       container_of(napi, struct ixgbe_q_vector, napi);
 	struct ixgbe_adapter *adapter = q_vector->adapter;
-	struct ixgbe_ring *rx_ring;
+	struct ixgbe_ring *rx_ring = NULL;
 	int work_done = 0;
 	long r_idx;
 
@@ -1055,6 +1057,56 @@ static int ixgbe_clean_rxonly(struct napi_struct *napi, int budget)
 	return work_done;
 }
 
+/**
+ * ixgbe_clean_rxonly_many - msix (aka one shot) rx clean routine
+ * @napi: napi struct with our devices info in it
+ * @budget: amount of work driver is allowed to do this pass, in packets
+ *
+ * This function will clean more than one rx queue associated with a
+ * q_vector.
+ **/
+static int ixgbe_clean_rxonly_many(struct napi_struct *napi, int budget)
+{
+	struct ixgbe_q_vector *q_vector =
+	                       container_of(napi, struct ixgbe_q_vector, napi);
+	struct ixgbe_adapter *adapter = q_vector->adapter;
+	struct net_device *netdev = adapter->netdev;
+	struct ixgbe_ring *rx_ring = NULL;
+	int work_done = 0, i;
+	long r_idx;
+	u16 enable_mask = 0;
+
+	/* attempt to distribute budget to each queue fairly, but don't allow
+	 * the budget to go below 1 because we'll exit polling */
+	budget /= (q_vector->rxr_count ?: 1);
+	budget = max(budget, 1);
+	r_idx = find_first_bit(q_vector->rxr_idx, adapter->num_rx_queues);
+	for (i = 0; i < q_vector->rxr_count; i++) {
+		rx_ring = &(adapter->rx_ring[r_idx]);
+#if defined(CONFIG_DCA) || defined(CONFIG_DCA_MODULE)
+		if (adapter->flags & IXGBE_FLAG_DCA_ENABLED)
+			ixgbe_update_rx_dca(adapter, rx_ring);
+#endif
+		ixgbe_clean_rx_irq(adapter, rx_ring, &work_done, budget);
+		enable_mask |= rx_ring->v_idx;
+		r_idx = find_next_bit(q_vector->rxr_idx, adapter->num_rx_queues,
+		                      r_idx + 1);
+	}
+
+	r_idx = find_first_bit(q_vector->rxr_idx, adapter->num_rx_queues);
+	rx_ring = &(adapter->rx_ring[r_idx]);
+	/* If all Rx work done, exit the polling mode */
+	if ((work_done == 0) || !netif_running(netdev)) {
+		netif_rx_complete(netdev, napi);
+		if (adapter->itr_setting & 3)
+			ixgbe_set_itr_msix(q_vector);
+		if (!test_bit(__IXGBE_DOWN, &adapter->state))
+			IXGBE_WRITE_REG(&adapter->hw, IXGBE_EIMS, enable_mask);
+		return 0;
+	}
+
+	return work_done;
+}
 static inline void map_vector_to_rxq(struct ixgbe_adapter *a, int v_idx,
 				     int r_idx)
 {
@@ -1813,10 +1865,16 @@ static void ixgbe_napi_enable_all(struct ixgbe_adapter *adapter)
 		q_vectors = 1;
 
 	for (q_idx = 0; q_idx < q_vectors; q_idx++) {
+		struct napi_struct *napi;
 		q_vector = &adapter->q_vector[q_idx];
 		if (!q_vector->rxr_count)
 			continue;
-		napi_enable(&q_vector->napi);
+		napi = &q_vector->napi;
+		if ((adapter->flags & IXGBE_FLAG_MSIX_ENABLED) &&
+		    (q_vector->rxr_count > 1))
+			napi->poll = &ixgbe_clean_rxonly_many;
+
+		napi_enable(napi);
 	}
 }