[PATCH net-next v4 05/14] ibmveth: Refactor RX interrupt control for MQ RX queues

@@ -21,6 +21,8 @@
 #include <linux/skbuff.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
 #include <linux/mm.h>
 #include <linux/pm.h>
 #include <linux/ethtool.h>

@@ -329,6 +331,203 @@ ibmveth_cleanup_rx_resources(struct ibmveth_adapter *adapter)
 	}
 }
 
+/**
+ * ibmveth_toggle_irq - Common helper to enable/disable queue interrupts
+ * @adapter: ibmveth adapter structure
+ * @queue_index: Index of the queue (0 for primary, 1+ for subordinate)
+ * @enable: true to enable, false to disable
+ *
+ * For queue 0 (primary), uses h_vio_signal() as it's registered via
+ * h_register_logical_lan(). For subordinate queues (1+), uses H_VIOCTL
+ * with H_ENABLE/DISABLE_VIO_INTERRUPT for per-queue interrupt control.
+ *
+ * Return: 0 on success, error code otherwise
+ */
+static int
+ibmveth_toggle_irq(struct ibmveth_adapter *adapter, int queue_index,
+		   bool enable)
+{
+	unsigned long rc;
+	unsigned long irq = adapter->queue_irq[queue_index];
+	const char *action = enable ? "enable" : "disable";
+
+	if (queue_index == 0) {
+		/* Primary queue: use h_vio_signal() */
+		rc = h_vio_signal(adapter->vdev->unit_address,
+				  enable ? VIO_IRQ_ENABLE : VIO_IRQ_DISABLE);
+	} else {
+		/* Subordinate queues: use H_VIOCTL with hardware IRQ */
+		struct irq_data *irq_data = irq_get_irq_data(irq);
+		irq_hw_number_t hwirq;
+		u64 vioctl_cmd = enable ? H_ENABLE_VIO_INTERRUPT :
+			H_DISABLE_VIO_INTERRUPT;
+
+		if (!irq_data) {
+			netdev_err(adapter->netdev,
+				   "Failed to get IRQ data for queue %d (virq=%lu)\n",
+				   queue_index, irq);
+			return -EINVAL;
+		}
+
+		hwirq = irqd_to_hwirq(irq_data);
+		rc = plpar_hcall_norets(H_VIOCTL,
+					adapter->vdev->unit_address,
+					vioctl_cmd,
+					hwirq, 0, 0);
+
+		if (rc == H_PARAMETER) {
+			/* H_PARAMETER is non-fatal when IRQ is already in
+			 * the requested state.
+			 */
+			netdev_warn_once(adapter->netdev,
+					 "H_VIOCTL %s IRQ returned H_PARAMETER for queue %d (hwirq=%lu)\n",
+					 action, queue_index, hwirq);
+			return 0;
+		}
+	}
+
+	if (rc)
+		netdev_err(adapter->netdev,
+			   "Failed to %s IRQ for queue %d, rc=%ld\n",
+			   action, queue_index, rc);
+	return rc;
+}
+
+/**
+ * ibmveth_disable_irq - Disable interrupt for a specific queue
+ * @adapter: ibmveth adapter structure
+ * @queue_index: Index of the queue (0 for primary, 1+ for subordinate)
+ *
+ * Return: 0 on success, error code otherwise
+ */
+static int
+ibmveth_disable_irq(struct ibmveth_adapter *adapter, int queue_index)
+{
+	return ibmveth_toggle_irq(adapter, queue_index, false);
+}
+
+/**
+ * ibmveth_enable_irq - Enable interrupt for a specific queue
+ * @adapter: ibmveth adapter structure
+ * @queue_index: Index of the queue (0 for primary, 1+ for subordinate)
+ *
+ * Return: 0 on success, error code otherwise
+ */
+static int
+ibmveth_enable_irq(struct ibmveth_adapter *adapter, int queue_index)
+{
+	return ibmveth_toggle_irq(adapter, queue_index, true);
+}
+
+/**
+ * ibmveth_setup_rx_interrupts - Register IRQs and enable NAPI
+ * @adapter: ibmveth adapter structure
+ *
+ * Registers interrupt handlers for all RX queues and enables NAPI polling.
+ * On error, cleans up any successfully registered IRQs before returning.
+ *
+ * Return: 0 on success, negative error code on failure
+ */
+static int
+ibmveth_setup_rx_interrupts(struct ibmveth_adapter *adapter)
+{
+	struct net_device *netdev = adapter->netdev;
+	int i, rc;
+
+	for (i = 0; i < adapter->num_rx_queues; i++) {
+		if (!adapter->queue_irq[i]) {
+			netdev_err(netdev, "queue %d has invalid IRQ (0)\n", i);
+			rc = -EINVAL;
+			goto err_free_irqs;
+		}
+
+		rc = request_irq(adapter->queue_irq[i], ibmveth_interrupt,
+				 0, netdev->name, &adapter->napi[i]);
+		if (rc) {
+			netdev_err(netdev,
+				   "request_irq() failed for irq 0x%x queue %d: %d\n",
+				   adapter->queue_irq[i], i, rc);
+			goto err_free_irqs;
+		}
+	}
+
+	for (i = 0; i < adapter->num_rx_queues; i++)
+		napi_enable(&adapter->napi[i]);
+
+	return 0;
+
+err_free_irqs:
+	while (--i >= 0)
+		free_irq(adapter->queue_irq[i], &adapter->napi[i]);
+	return rc;
+}
+
+/**
+ * ibmveth_cleanup_rx_interrupts - Mask PHYP, disable NAPI, free IRQs
+ * @adapter: ibmveth adapter structure
+ *
+ * Tears down RX interrupt delivery for all queues. Mask PHYP before
+ * napi_disable so ibmveth_interrupt cannot return IRQ_HANDLED without
+ * masking (same storm window as scale-down). Safe for close and for
+ * open failure after setup_rx_interrupts() already unmasked PHYP.
+ */
+static void
+ibmveth_cleanup_rx_interrupts(struct ibmveth_adapter *adapter)
+{
+	int i;
+
+	for (i = 0; i < adapter->num_rx_queues; i++) {
+		if (adapter->queue_irq[i]) {
+			ibmveth_disable_irq(adapter, i);
+			synchronize_irq(adapter->queue_irq[i]);
+		}
+	}
+
+	for (i = 0; i < adapter->num_rx_queues; i++)
+		napi_disable(&adapter->napi[i]);
+
+	for (i = 0; i < adapter->num_rx_queues; i++) {
+		if (adapter->queue_irq[i])
+			free_irq(adapter->queue_irq[i], &adapter->napi[i]);
+	}
+
+	/* Dispose IRQ mappings for subordinate queues (1-15).
+	 * Queue 0 uses netdev->irq from device tree, not irq_create_mapping().
+	 */
+	for (i = 1; i < adapter->num_rx_queues; i++) {
+		if (adapter->queue_irq[i]) {
+			irq_dispose_mapping(adapter->queue_irq[i]);
+			adapter->queue_irq[i] = 0;
+		}
+	}
+
+	/* Queue 0 uses netdev->irq; leave queue_irq[0] for next open. */
+}
+
+/**
+ * ibmveth_schedule_rx_queue - Mask PHYP IRQ and schedule NAPI for one RX queue
+ * @adapter: ibmveth adapter structure
+ * @qindex: RX queue index
+ *
+ * Shared by the IRQ handler and process-context kick paths (open, resume,
+ * pool sysfs, netpoll). Keep ibmveth_interrupt() as the IRQ-only wrapper.
+ */
+static void ibmveth_schedule_rx_queue(struct ibmveth_adapter *adapter,
+				      int qindex)
+{
+	struct napi_struct *napi = &adapter->napi[qindex];
+	unsigned long lpar_rc;
+
+	if (WARN_ON(qindex < 0 || qindex >= adapter->num_rx_queues))
+		return;
+
+	if (napi_schedule_prep(napi)) {
+		lpar_rc = ibmveth_disable_irq(adapter, qindex);
+		WARN_ON(lpar_rc != H_SUCCESS);
+		__napi_schedule(napi);
+	}
+}
+
 /* setup the initial settings for a buffer pool */
 static void ibmveth_init_buffer_pool(struct ibmveth_buff_pool *pool,
 				     u32 pool_index, u32 pool_size,

@@ -947,8 +1146,6 @@ static int ibmveth_open(struct net_device *netdev)
 
 	netdev_dbg(netdev, "open starting\n");
 
-	napi_enable(&adapter->napi[0]);
-
 	for (i = 0; i < IBMVETH_NUM_BUFF_POOLS; i++)
 		rxq_entries += adapter->rx_buff_pool[0][i].size;
 

@@ -972,7 +1169,8 @@ static int ibmveth_open(struct net_device *netdev)
 					adapter->rx_queue[0].queue_len;
 	rxq_desc.fields.address = adapter->rx_queue[0].queue_dma;
 
-	h_vio_signal(adapter->vdev->unit_address, VIO_IRQ_DISABLE);
+	adapter->queue_irq[0] = netdev->irq;
+	ibmveth_disable_irq(adapter, 0);
 
 	lpar_rc = ibmveth_register_logical_lan(adapter, rxq_desc, mac_address);
 

@@ -993,21 +1191,16 @@ static int ibmveth_open(struct net_device *netdev)
 	if (rc)
 		goto out_free_tx_ltb;
 
-	netdev_dbg(netdev, "registering irq 0x%x\n", netdev->irq);
-	rc = request_irq(netdev->irq, ibmveth_interrupt, 0, netdev->name,
-			 netdev);
-	if (rc != 0) {
-		netdev_err(netdev, "unable to request irq 0x%x, rc %d\n",
-			   netdev->irq, rc);
+	rc = ibmveth_setup_rx_interrupts(adapter);
+	if (rc) {
 		do {
 			lpar_rc = h_free_logical_lan(adapter->vdev->unit_address);
 		} while (H_IS_LONG_BUSY(lpar_rc) || (lpar_rc == H_BUSY));
-
 		goto out_free_buffer_pools;
 	}
 
 	netdev_dbg(netdev, "initial replenish cycle\n");
-	ibmveth_interrupt(netdev->irq, netdev);
+	ibmveth_schedule_rx_queue(adapter, 0);
 
 	netif_tx_start_all_queues(netdev);
 

@@ -1024,7 +1217,6 @@ static int ibmveth_open(struct net_device *netdev)
 out_free_filter_list:
 	ibmveth_free_filter_list(adapter);
 out:
-	napi_disable(&adapter->napi[0]);
 	return rc;
 }
 

@@ -1036,11 +1228,10 @@ static int ibmveth_close(struct net_device *netdev)
 
 	netdev_dbg(netdev, "close starting\n");
 
-	napi_disable(&adapter->napi[0]);
-
 	netif_tx_stop_all_queues(netdev);
 
-	h_vio_signal(adapter->vdev->unit_address, VIO_IRQ_DISABLE);
+	/* PHYP mask + napi_disable + free_irq live in cleanup_rx_interrupts */
+	ibmveth_cleanup_rx_interrupts(adapter);
 
 	do {
 		lpar_rc = h_free_logical_lan(adapter->vdev->unit_address);

@@ -1051,8 +1242,6 @@ static int ibmveth_close(struct net_device *netdev)
 			   "continuing with close\n", lpar_rc);
 	}
 
-	free_irq(netdev->irq, netdev);
-
 	ibmveth_update_rx_no_buffer(adapter);
 
 	ibmveth_free_buffer_pools(adapter);

@@ -1798,15 +1987,14 @@ static int ibmveth_poll(struct napi_struct *napi, int budget)
 	/* We think we are done - reenable interrupts,
 	 * then check once more to make sure we are done.
 	 */
-	lpar_rc = h_vio_signal(adapter->vdev->unit_address, VIO_IRQ_ENABLE);
+	lpar_rc = ibmveth_enable_irq(adapter, 0);
 	if (WARN_ON(lpar_rc != H_SUCCESS)) {
 		schedule_work(&adapter->work);
 		goto out;
 	}
 
 	if (ibmveth_rxq_pending_buffer(adapter) && napi_schedule(napi)) {
-		lpar_rc = h_vio_signal(adapter->vdev->unit_address,
-				       VIO_IRQ_DISABLE);
+		lpar_rc = ibmveth_disable_irq(adapter, 0);
 		goto restart_poll;
 	}
 

@@ -1816,16 +2004,16 @@ static int ibmveth_poll(struct napi_struct *napi, int budget)
 
 static irqreturn_t ibmveth_interrupt(int irq, void *dev_instance)
 {
-	struct net_device *netdev = dev_instance;
+	struct napi_struct *napi = dev_instance;
+	struct net_device *netdev = napi->dev;
 	struct ibmveth_adapter *adapter = netdev_priv(netdev);
-	unsigned long lpar_rc;
+	int qindex;
 
-	if (napi_schedule_prep(&adapter->napi[0])) {
-		lpar_rc = h_vio_signal(adapter->vdev->unit_address,
-				       VIO_IRQ_DISABLE);
-		WARN_ON(lpar_rc != H_SUCCESS);
-		__napi_schedule(&adapter->napi[0]);
-	}
+	qindex = napi - adapter->napi;
+	if (WARN_ON(qindex < 0 || qindex >= adapter->num_rx_queues))
+		return IRQ_NONE;
+
+	ibmveth_schedule_rx_queue(adapter, qindex);
 	return IRQ_HANDLED;
 }
 

@@ -1930,8 +2118,10 @@ static int ibmveth_change_mtu(struct net_device *dev, int new_mtu)
 #ifdef CONFIG_NET_POLL_CONTROLLER
 static void ibmveth_poll_controller(struct net_device *dev)
 {
-	ibmveth_replenish_task(netdev_priv(dev));
-	ibmveth_interrupt(dev->irq, dev);
+	struct ibmveth_adapter *adapter = netdev_priv(dev);
+
+	ibmveth_replenish_task(adapter);
+	ibmveth_schedule_rx_queue(adapter, 0);
 }
 #endif
 

@@ -2343,8 +2533,8 @@ static ssize_t veth_pool_store(struct kobject *kobj, struct attribute *attr,
 	}
 	rtnl_unlock();
 
-	/* kick the interrupt handler to allocate/deallocate pools */
-	ibmveth_interrupt(netdev->irq, netdev);
+	/* kick RX processing to allocate/deallocate pools */
+	ibmveth_schedule_rx_queue(adapter, 0);
 	return count;
 
 unlock_err:

@@ -2384,7 +2574,9 @@ static struct kobj_type ktype_veth_pool = {
 static int ibmveth_resume(struct device *dev)
 {
 	struct net_device *netdev = dev_get_drvdata(dev);
-	ibmveth_interrupt(netdev->irq, netdev);
+	struct ibmveth_adapter *adapter = netdev_priv(netdev);
+
+	ibmveth_schedule_rx_queue(adapter, 0);
 	return 0;
 }