net: ena: ethtool: support set_channels callback

Set channels callback enables the user to change the count of queues
used by the driver using ethtool. We decided to currently support only
equal number of rx and tx queues, this might change in the future.

Also rename dev_up to dev_was_up in ena_update_queue_count() to make
it clearer.
Signed-off-by: Sameeh Jubran <sameehj@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/amazon/ena/ena_ethtool.c

@@ -738,6 +738,18 @@ static void ena_get_channels(struct net_device *netdev,
 	channels->combined_count = adapter->num_io_queues;
 }
 
+static int ena_set_channels(struct net_device *netdev,
+			    struct ethtool_channels *channels)
+{
+	struct ena_adapter *adapter = netdev_priv(netdev);
+	u32 count = channels->combined_count;
+	/* The check for max value is already done in ethtool */
+	if (count < ENA_MIN_NUM_IO_QUEUES)
+		return -EINVAL;
+
+	return ena_update_queue_count(adapter, count);
+}
+
 static int ena_get_tunable(struct net_device *netdev,
 			   const struct ethtool_tunable *tuna, void *data)
 {
@@ -801,6 +813,7 @@ static const struct ethtool_ops ena_ethtool_ops = {
 	.get_rxfh		= ena_get_rxfh,
 	.set_rxfh		= ena_set_rxfh,
 	.get_channels		= ena_get_channels,
+	.set_channels		= ena_set_channels,
 	.get_tunable		= ena_get_tunable,
 	.set_tunable		= ena_set_tunable,
 };

drivers/net/ethernet/amazon/ena/ena_netdev.c

@@ -2043,14 +2043,30 @@ int ena_update_queue_sizes(struct ena_adapter *adapter,
 			   u32 new_tx_size,
 			   u32 new_rx_size)
 {
-	bool dev_up;
+	bool dev_was_up;
 
-	dev_up = test_bit(ENA_FLAG_DEV_UP, &adapter->flags);
+	dev_was_up = test_bit(ENA_FLAG_DEV_UP, &adapter->flags);
 	ena_close(adapter->netdev);
 	adapter->requested_tx_ring_size = new_tx_size;
 	adapter->requested_rx_ring_size = new_rx_size;
 	ena_init_io_rings(adapter);
-	return dev_up ? ena_up(adapter) : 0;
+	return dev_was_up ? ena_up(adapter) : 0;
+}
+
+int ena_update_queue_count(struct ena_adapter *adapter, u32 new_channel_count)
+{
+	struct ena_com_dev *ena_dev = adapter->ena_dev;
+	bool dev_was_up;
+
+	dev_was_up = test_bit(ENA_FLAG_DEV_UP, &adapter->flags);
+	ena_close(adapter->netdev);
+	adapter->num_io_queues = new_channel_count;
+	/* We need to destroy the rss table so that the indirection
+	 * table will be reinitialized by ena_up()
+	 */
+	ena_com_rss_destroy(ena_dev);
+	ena_init_io_rings(adapter);
+	return dev_was_up ? ena_open(adapter->netdev) : 0;
 }
 
 static void ena_tx_csum(struct ena_com_tx_ctx *ena_tx_ctx, struct sk_buff *skb)

drivers/net/ethernet/amazon/ena/ena_netdev.h

@@ -82,6 +82,8 @@
 #define ENA_DEFAULT_RING_SIZE	(1024)
 #define ENA_MIN_RING_SIZE	(256)
 
+#define ENA_MIN_NUM_IO_QUEUES	(1)
+
 #define ENA_TX_WAKEUP_THRESH		(MAX_SKB_FRAGS + 2)
 #define ENA_DEFAULT_RX_COPYBREAK	(256 - NET_IP_ALIGN)
 
@@ -388,6 +390,7 @@ void ena_dump_stats_to_buf(struct ena_adapter *adapter, u8 *buf);
 int ena_update_queue_sizes(struct ena_adapter *adapter,
 			   u32 new_tx_size,
 			   u32 new_rx_size);
+int ena_update_queue_count(struct ena_adapter *adapter, u32 new_channel_count);
 
 int ena_get_sset_count(struct net_device *netdev, int sset);