igb: Link queues to NAPI instances

Link queues to NAPI instances via netdev-genl API. This is required to use
XDP/ZC busy polling. See commit 5ef44b3 ("xsk: Bring back busy polling
support") for details.

This also allows users to query the info with netlink:

|$ ./tools/net/ynl/pyynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \
|                               --dump queue-get --json='{"ifindex": 2}'
|[{'id': 0, 'ifindex': 2, 'napi-id': 8201, 'type': 'rx'},
| {'id': 1, 'ifindex': 2, 'napi-id': 8202, 'type': 'rx'},
| {'id': 2, 'ifindex': 2, 'napi-id': 8203, 'type': 'rx'},
| {'id': 3, 'ifindex': 2, 'napi-id': 8204, 'type': 'rx'},
| {'id': 0, 'ifindex': 2, 'napi-id': 8201, 'type': 'tx'},
| {'id': 1, 'ifindex': 2, 'napi-id': 8202, 'type': 'tx'},
| {'id': 2, 'ifindex': 2, 'napi-id': 8203, 'type': 'tx'},
| {'id': 3, 'ifindex': 2, 'napi-id': 8204, 'type': 'tx'}]

Add rtnl locking to PCI error handlers, because netif_queue_set_napi()
requires the lock held.

While at __igb_open() use RCT coding style.

Signed-off-by: Kurt Kanzenbach <[email protected]>
Reviewed-by: Joe Damato <[email protected]>
Tested-by: Sweta Kumari <[email protected]>
Signed-off-by: Tony Nguyen <[email protected]>

Author: shifty91

drivers/net/ethernet/intel/igb/igb.h

@@ -722,6 +722,8 @@ enum igb_boards {
 
 extern char igb_driver_name[];
 
+void igb_set_queue_napi(struct igb_adapter *adapter, int q_idx,
+			struct napi_struct *napi);
 int igb_xmit_xdp_ring(struct igb_adapter *adapter,
 		      struct igb_ring *ring,
 		      struct xdp_frame *xdpf);

drivers/net/ethernet/intel/igb/igb_main.c

@@ -2099,22 +2099,42 @@ static void igb_check_swap_media(struct igb_adapter *adapter)
 	wr32(E1000_CTRL_EXT, ctrl_ext);
 }
 
+void igb_set_queue_napi(struct igb_adapter *adapter, int vector,
+			struct napi_struct *napi)
+{
+	struct igb_q_vector *q_vector = adapter->q_vector[vector];
+
+	if (q_vector->rx.ring)
+		netif_queue_set_napi(adapter->netdev,
+				     q_vector->rx.ring->queue_index,
+				     NETDEV_QUEUE_TYPE_RX, napi);
+
+	if (q_vector->tx.ring)
+		netif_queue_set_napi(adapter->netdev,
+				     q_vector->tx.ring->queue_index,
+				     NETDEV_QUEUE_TYPE_TX, napi);
+}
+
 /**
  *  igb_up - Open the interface and prepare it to handle traffic
  *  @adapter: board private structure
  **/
 int igb_up(struct igb_adapter *adapter)
 {
 	struct e1000_hw *hw = &adapter->hw;
+	struct napi_struct *napi;
 	int i;
 
 	/* hardware has been reset, we need to reload some things */
 	igb_configure(adapter);
 
 	clear_bit(__IGB_DOWN, &adapter->state);
 
-	for (i = 0; i < adapter->num_q_vectors; i++)
-		napi_enable(&(adapter->q_vector[i]->napi));
+	for (i = 0; i < adapter->num_q_vectors; i++) {
+		napi = &adapter->q_vector[i]->napi;
+		napi_enable(napi);
+		igb_set_queue_napi(adapter, i, napi);
+	}
 
 	if (adapter->flags & IGB_FLAG_HAS_MSIX)
 		igb_configure_msix(adapter);
@@ -2184,6 +2204,7 @@ void igb_down(struct igb_adapter *adapter)
 	for (i = 0; i < adapter->num_q_vectors; i++) {
 		if (adapter->q_vector[i]) {
 			napi_synchronize(&adapter->q_vector[i]->napi);
+			igb_set_queue_napi(adapter, i, NULL);
 			napi_disable(&adapter->q_vector[i]->napi);
 		}
 	}
@@ -4116,8 +4137,9 @@ static int igb_sw_init(struct igb_adapter *adapter)
 static int __igb_open(struct net_device *netdev, bool resuming)
 {
 	struct igb_adapter *adapter = netdev_priv(netdev);
-	struct e1000_hw *hw = &adapter->hw;
 	struct pci_dev *pdev = adapter->pdev;
+	struct e1000_hw *hw = &adapter->hw;
+	struct napi_struct *napi;
 	int err;
 	int i;
 
@@ -4169,8 +4191,11 @@ static int __igb_open(struct net_device *netdev, bool resuming)
 	/* From here on the code is the same as igb_up() */
 	clear_bit(__IGB_DOWN, &adapter->state);
 
-	for (i = 0; i < adapter->num_q_vectors; i++)
-		napi_enable(&(adapter->q_vector[i]->napi));
+	for (i = 0; i < adapter->num_q_vectors; i++) {
+		napi = &adapter->q_vector[i]->napi;
+		napi_enable(napi);
+		igb_set_queue_napi(adapter, i, napi);
+	}
 
 	/* Clear any pending interrupts. */
 	rd32(E1000_TSICR);
@@ -9677,8 +9702,11 @@ static pci_ers_result_t igb_io_error_detected(struct pci_dev *pdev,
 	if (state == pci_channel_io_perm_failure)
 		return PCI_ERS_RESULT_DISCONNECT;
 
+	rtnl_lock();
 	if (netif_running(netdev))
 		igb_down(adapter);
+	rtnl_unlock();
+
 	pci_disable_device(pdev);
 
 	/* Request a slot reset. */
@@ -9737,16 +9765,21 @@ static void igb_io_resume(struct pci_dev *pdev)
 	struct net_device *netdev = pci_get_drvdata(pdev);
 	struct igb_adapter *adapter = netdev_priv(netdev);
 
+	rtnl_lock();
 	if (netif_running(netdev)) {
 		if (!test_bit(__IGB_DOWN, &adapter->state)) {
 			dev_dbg(&pdev->dev, "Resuming from non-fatal error, do nothing.\n");
+			rtnl_unlock();
 			return;
 		}
+
 		if (igb_up(adapter)) {
 			dev_err(&pdev->dev, "igb_up failed after reset\n");
+			rtnl_unlock();
 			return;
 		}
 	}
+	rtnl_unlock();
 
 	netif_device_attach(netdev);