Merge branch 'queues'

Jakub Kicinski says:

====================
net: add netif_set_real_num_queues() for device reconfig

This short set adds a helper to make the implementation of
two-phase NIC reconfig easier.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/nfp_net_common.c

@@ -3281,17 +3281,12 @@ static int nfp_net_dp_swap_enable(struct nfp_net *nn, struct nfp_net_dp *dp)
 	for (r = 0; r <	nn->max_r_vecs; r++)
 		nfp_net_vector_assign_rings(&nn->dp, &nn->r_vecs[r], r);
 
-	err = netif_set_real_num_rx_queues(nn->dp.netdev, nn->dp.num_rx_rings);
+	err = netif_set_real_num_queues(nn->dp.netdev,
+					nn->dp.num_stack_tx_rings,
+					nn->dp.num_rx_rings);
 	if (err)
 		return err;
 
-	if (nn->dp.netdev->real_num_tx_queues != nn->dp.num_stack_tx_rings) {
-		err = netif_set_real_num_tx_queues(nn->dp.netdev,
-						   nn->dp.num_stack_tx_rings);
-		if (err)
-			return err;
-	}
-
 	return nfp_net_set_config_and_enable(nn);
 }
 

include/linux/netdevice.h

@@ -3916,6 +3916,8 @@ static inline int netif_set_real_num_rx_queues(struct net_device *dev,
 	return 0;
 }
 #endif
+int netif_set_real_num_queues(struct net_device *dev,
+			      unsigned int txq, unsigned int rxq);
 
 static inline struct netdev_rx_queue *
 __netif_get_rx_queue(struct net_device *dev, unsigned int rxq)

net/core/dev.c

@@ -2973,6 +2973,50 @@ int netif_set_real_num_rx_queues(struct net_device *dev, unsigned int rxq)
 EXPORT_SYMBOL(netif_set_real_num_rx_queues);
 #endif
 
+/**
+ *	netif_set_real_num_queues - set actual number of RX and TX queues used
+ *	@dev: Network device
+ *	@txq: Actual number of TX queues
+ *	@rxq: Actual number of RX queues
+ *
+ *	Set the real number of both TX and RX queues.
+ *	Does nothing if the number of queues is already correct.
+ */
+int netif_set_real_num_queues(struct net_device *dev,
+			      unsigned int txq, unsigned int rxq)
+{
+	unsigned int old_rxq = dev->real_num_rx_queues;
+	int err;
+
+	if (txq < 1 || txq > dev->num_tx_queues ||
+	    rxq < 1 || rxq > dev->num_rx_queues)
+		return -EINVAL;
+
+	/* Start from increases, so the error path only does decreases -
+	 * decreases can't fail.
+	 */
+	if (rxq > dev->real_num_rx_queues) {
+		err = netif_set_real_num_rx_queues(dev, rxq);
+		if (err)
+			return err;
+	}
+	if (txq > dev->real_num_tx_queues) {
+		err = netif_set_real_num_tx_queues(dev, txq);
+		if (err)
+			goto undo_rx;
+	}
+	if (rxq < dev->real_num_rx_queues)
+		WARN_ON(netif_set_real_num_rx_queues(dev, rxq));
+	if (txq < dev->real_num_tx_queues)
+		WARN_ON(netif_set_real_num_tx_queues(dev, txq));
+
+	return 0;
+undo_rx:
+	WARN_ON(netif_set_real_num_rx_queues(dev, old_rxq));
+	return err;
+}
+EXPORT_SYMBOL(netif_set_real_num_queues);
+
 /**
  * netif_get_num_default_rss_queues - default number of RSS queues
  *