eth: iavf: extend the netdev_lock usage

iavf uses the netdev->lock already to protect shapers.
In an upcoming series we'll try to protect NAPI instances
with netdev->lock.

We need to modify the protection a bit. All NAPI related
calls in the driver need to be consistently under the lock.
This will allow us to easily switch to a "we already hold
the lock" NAPI API later.

register_netdevice(), OTOH, must not be called under
the netdev_lock() as we do not intend to have an
"already locked" version of this call.

Link: https://patch.msgid.link/20250111071339.3709071-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: kuba-moo

drivers/net/ethernet/intel/iavf/iavf_main.c

@@ -1968,6 +1968,7 @@ static int iavf_reinit_interrupt_scheme(struct iavf_adapter *adapter, bool runni
 static void iavf_finish_config(struct work_struct *work)
 {
 	struct iavf_adapter *adapter;
+	bool netdev_released = false;
 	int pairs, err;
 
 	adapter = container_of(work, struct iavf_adapter, finish_config);
@@ -1988,7 +1989,16 @@ static void iavf_finish_config(struct work_struct *work)
 
 	switch (adapter->state) {
 	case __IAVF_DOWN:
+		/* Set the real number of queues when reset occurs while
+		 * state == __IAVF_DOWN
+		 */
+		pairs = adapter->num_active_queues;
+		netif_set_real_num_rx_queues(adapter->netdev, pairs);
+		netif_set_real_num_tx_queues(adapter->netdev, pairs);
+
 		if (adapter->netdev->reg_state != NETREG_REGISTERED) {
+			mutex_unlock(&adapter->netdev->lock);
+			netdev_released = true;
 			err = register_netdevice(adapter->netdev);
 			if (err) {
 				dev_err(&adapter->pdev->dev, "Unable to register netdev (%d)\n",
@@ -2003,11 +2013,7 @@ static void iavf_finish_config(struct work_struct *work)
 				goto out;
 			}
 		}
-
-		/* Set the real number of queues when reset occurs while
-		 * state == __IAVF_DOWN
-		 */
-		fallthrough;
+		break;
 	case __IAVF_RUNNING:
 		pairs = adapter->num_active_queues;
 		netif_set_real_num_rx_queues(adapter->netdev, pairs);
@@ -2020,7 +2026,8 @@ static void iavf_finish_config(struct work_struct *work)
 
 out:
 	mutex_unlock(&adapter->crit_lock);
-	mutex_unlock(&adapter->netdev->lock);
+	if (!netdev_released)
+		mutex_unlock(&adapter->netdev->lock);
 	rtnl_unlock();
 }
 
@@ -2713,12 +2720,16 @@ static void iavf_watchdog_task(struct work_struct *work)
 	struct iavf_adapter *adapter = container_of(work,
 						    struct iavf_adapter,
 						    watchdog_task.work);
+	struct net_device *netdev = adapter->netdev;
 	struct iavf_hw *hw = &adapter->hw;
 	u32 reg_val;
 
+	mutex_lock(&netdev->lock);
 	if (!mutex_trylock(&adapter->crit_lock)) {
-		if (adapter->state == __IAVF_REMOVE)
+		if (adapter->state == __IAVF_REMOVE) {
+			mutex_unlock(&netdev->lock);
 			return;
+		}
 
 		goto restart_watchdog;
 	}
@@ -2730,30 +2741,35 @@ static void iavf_watchdog_task(struct work_struct *work)
 	case __IAVF_STARTUP:
 		iavf_startup(adapter);
 		mutex_unlock(&adapter->crit_lock);
+		mutex_unlock(&netdev->lock);
 		queue_delayed_work(adapter->wq, &adapter->watchdog_task,
 				   msecs_to_jiffies(30));
 		return;
 	case __IAVF_INIT_VERSION_CHECK:
 		iavf_init_version_check(adapter);
 		mutex_unlock(&adapter->crit_lock);
+		mutex_unlock(&netdev->lock);
 		queue_delayed_work(adapter->wq, &adapter->watchdog_task,
 				   msecs_to_jiffies(30));
 		return;
 	case __IAVF_INIT_GET_RESOURCES:
 		iavf_init_get_resources(adapter);
 		mutex_unlock(&adapter->crit_lock);
+		mutex_unlock(&netdev->lock);
 		queue_delayed_work(adapter->wq, &adapter->watchdog_task,
 				   msecs_to_jiffies(1));
 		return;
 	case __IAVF_INIT_EXTENDED_CAPS:
 		iavf_init_process_extended_caps(adapter);
 		mutex_unlock(&adapter->crit_lock);
+		mutex_unlock(&netdev->lock);
 		queue_delayed_work(adapter->wq, &adapter->watchdog_task,
 				   msecs_to_jiffies(1));
 		return;
 	case __IAVF_INIT_CONFIG_ADAPTER:
 		iavf_init_config_adapter(adapter);
 		mutex_unlock(&adapter->crit_lock);
+		mutex_unlock(&netdev->lock);
 		queue_delayed_work(adapter->wq, &adapter->watchdog_task,
 				   msecs_to_jiffies(1));
 		return;
@@ -2765,6 +2781,7 @@ static void iavf_watchdog_task(struct work_struct *work)
 			 * as it can loop forever
 			 */
 			mutex_unlock(&adapter->crit_lock);
+			mutex_unlock(&netdev->lock);
 			return;
 		}
 		if (++adapter->aq_wait_count > IAVF_AQ_MAX_ERR) {
@@ -2773,13 +2790,15 @@ static void iavf_watchdog_task(struct work_struct *work)
 			adapter->flags |= IAVF_FLAG_PF_COMMS_FAILED;
 			iavf_shutdown_adminq(hw);
 			mutex_unlock(&adapter->crit_lock);
+			mutex_unlock(&netdev->lock);
 			queue_delayed_work(adapter->wq,
 					   &adapter->watchdog_task, (5 * HZ));
 			return;
 		}
 		/* Try again from failed step*/
 		iavf_change_state(adapter, adapter->last_state);
 		mutex_unlock(&adapter->crit_lock);
+		mutex_unlock(&netdev->lock);
 		queue_delayed_work(adapter->wq, &adapter->watchdog_task, HZ);
 		return;
 	case __IAVF_COMM_FAILED:
@@ -2792,6 +2811,7 @@ static void iavf_watchdog_task(struct work_struct *work)
 			iavf_change_state(adapter, __IAVF_INIT_FAILED);
 			adapter->flags &= ~IAVF_FLAG_PF_COMMS_FAILED;
 			mutex_unlock(&adapter->crit_lock);
+			mutex_unlock(&netdev->lock);
 			return;
 		}
 		reg_val = rd32(hw, IAVF_VFGEN_RSTAT) &
@@ -2811,12 +2831,14 @@ static void iavf_watchdog_task(struct work_struct *work)
 		adapter->aq_required = 0;
 		adapter->current_op = VIRTCHNL_OP_UNKNOWN;
 		mutex_unlock(&adapter->crit_lock);
+		mutex_unlock(&netdev->lock);
 		queue_delayed_work(adapter->wq,
 				   &adapter->watchdog_task,
 				   msecs_to_jiffies(10));
 		return;
 	case __IAVF_RESETTING:
 		mutex_unlock(&adapter->crit_lock);
+		mutex_unlock(&netdev->lock);
 		queue_delayed_work(adapter->wq, &adapter->watchdog_task,
 				   HZ * 2);
 		return;
@@ -2847,6 +2869,7 @@ static void iavf_watchdog_task(struct work_struct *work)
 	case __IAVF_REMOVE:
 	default:
 		mutex_unlock(&adapter->crit_lock);
+		mutex_unlock(&netdev->lock);
 		return;
 	}
 
@@ -2858,12 +2881,14 @@ static void iavf_watchdog_task(struct work_struct *work)
 		dev_err(&adapter->pdev->dev, "Hardware reset detected\n");
 		iavf_schedule_reset(adapter, IAVF_FLAG_RESET_PENDING);
 		mutex_unlock(&adapter->crit_lock);
+		mutex_unlock(&netdev->lock);
 		queue_delayed_work(adapter->wq,
 				   &adapter->watchdog_task, HZ * 2);
 		return;
 	}
 
 	mutex_unlock(&adapter->crit_lock);
+	mutex_unlock(&netdev->lock);
 restart_watchdog:
 	if (adapter->state >= __IAVF_DOWN)
 		queue_work(adapter->wq, &adapter->adminq_task);
@@ -4340,14 +4365,17 @@ static int iavf_open(struct net_device *netdev)
 		return -EIO;
 	}
 
+	mutex_lock(&netdev->lock);
 	while (!mutex_trylock(&adapter->crit_lock)) {
 		/* If we are in __IAVF_INIT_CONFIG_ADAPTER state the crit_lock
 		 * is already taken and iavf_open is called from an upper
 		 * device's notifier reacting on NETDEV_REGISTER event.
 		 * We have to leave here to avoid dead lock.
 		 */
-		if (adapter->state == __IAVF_INIT_CONFIG_ADAPTER)
+		if (adapter->state == __IAVF_INIT_CONFIG_ADAPTER) {
+			mutex_unlock(&netdev->lock);
 			return -EBUSY;
+		}
 
 		usleep_range(500, 1000);
 	}
@@ -4396,6 +4424,7 @@ static int iavf_open(struct net_device *netdev)
 	iavf_irq_enable(adapter, true);
 
 	mutex_unlock(&adapter->crit_lock);
+	mutex_unlock(&netdev->lock);
 
 	return 0;
 
@@ -4408,6 +4437,7 @@ static int iavf_open(struct net_device *netdev)
 	iavf_free_all_tx_resources(adapter);
 err_unlock:
 	mutex_unlock(&adapter->crit_lock);
+	mutex_unlock(&netdev->lock);
 
 	return err;
 }
@@ -4429,10 +4459,12 @@ static int iavf_close(struct net_device *netdev)
 	u64 aq_to_restore;
 	int status;
 
+	mutex_lock(&netdev->lock);
 	mutex_lock(&adapter->crit_lock);
 
 	if (adapter->state <= __IAVF_DOWN_PENDING) {
 		mutex_unlock(&adapter->crit_lock);
+		mutex_unlock(&netdev->lock);
 		return 0;
 	}
 
@@ -4466,6 +4498,7 @@ static int iavf_close(struct net_device *netdev)
 	iavf_free_traffic_irqs(adapter);
 
 	mutex_unlock(&adapter->crit_lock);
+	mutex_unlock(&netdev->lock);
 
 	/* We explicitly don't free resources here because the hardware is
 	 * still active and can DMA into memory. Resources are cleared in
@@ -5342,6 +5375,7 @@ static int iavf_suspend(struct device *dev_d)
 
 	netif_device_detach(netdev);
 
+	mutex_lock(&netdev->lock);
 	mutex_lock(&adapter->crit_lock);
 
 	if (netif_running(netdev)) {
@@ -5353,6 +5387,7 @@ static int iavf_suspend(struct device *dev_d)
 	iavf_reset_interrupt_capability(adapter);
 
 	mutex_unlock(&adapter->crit_lock);
+	mutex_unlock(&netdev->lock);
 
 	return 0;
 }
@@ -5451,6 +5486,7 @@ static void iavf_remove(struct pci_dev *pdev)
 	if (netdev->reg_state == NETREG_REGISTERED)
 		unregister_netdev(netdev);
 
+	mutex_lock(&netdev->lock);
 	mutex_lock(&adapter->crit_lock);
 	dev_info(&adapter->pdev->dev, "Removing device\n");
 	iavf_change_state(adapter, __IAVF_REMOVE);
@@ -5487,6 +5523,7 @@ static void iavf_remove(struct pci_dev *pdev)
 	mutex_destroy(&hw->aq.asq_mutex);
 	mutex_unlock(&adapter->crit_lock);
 	mutex_destroy(&adapter->crit_lock);
+	mutex_unlock(&netdev->lock);
 
 	iounmap(hw->hw_addr);
 	pci_release_regions(pdev);