[PATCH net 1/5] ibmvnic: harden interrupt handler

[Thomas Falcon]

Move most interrupt handler processing into a tasklet, and
introduce a delay after re-enabling interrupts to fix timing
issues encountered in hardware testing.

Signed-off-by: Thomas Falcon <tlfalcon at linux.vnet.ibm.com>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 21 +++++++++++++++++++--
 drivers/net/ethernet/ibm/ibmvnic.h |  1 +
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index c125966..09071bf 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -3414,6 +3414,18 @@ static void ibmvnic_handle_crq(union ibmvnic_crq *crq,
 static irqreturn_t ibmvnic_interrupt(int irq, void *instance)
 {
 	struct ibmvnic_adapter *adapter = instance;
+	unsigned long flags;
+
+	spin_lock_irqsave(&adapter->crq.lock, flags);
+	vio_disable_interrupts(adapter->vdev);
+	tasklet_schedule(&adapter->tasklet);
+	spin_unlock_irqrestore(&adapter->crq.lock, flags);
+	return IRQ_HANDLED;
+}
+
+static void ibmvnic_tasklet(void *data)
+{
+	struct ibmvnic_adapter *adapter = data;
 	struct ibmvnic_crq_queue *queue = &adapter->crq;
 	struct vio_dev *vdev = adapter->vdev;
 	union ibmvnic_crq *crq;
@@ -3421,7 +3433,6 @@ static irqreturn_t ibmvnic_interrupt(int irq, void *instance)
 	bool done = false;
 
 	spin_lock_irqsave(&queue->lock, flags);
-	vio_disable_interrupts(vdev);
 	while (!done) {
 		/* Pull all the valid messages off the CRQ */
 		while ((crq = ibmvnic_next_crq(adapter)) != NULL) {
@@ -3429,6 +3440,8 @@ static irqreturn_t ibmvnic_interrupt(int irq, void *instance)
 			crq->generic.first = 0;
 		}
 		vio_enable_interrupts(vdev);
+		/* delay in case of firmware hiccup */
+		mdelay(10);
 		crq = ibmvnic_next_crq(adapter);
 		if (crq) {
 			vio_disable_interrupts(vdev);
@@ -3439,7 +3452,6 @@ static irqreturn_t ibmvnic_interrupt(int irq, void *instance)
 		}
 	}
 	spin_unlock_irqrestore(&queue->lock, flags);
-	return IRQ_HANDLED;
 }
 
 static int ibmvnic_reenable_crq_queue(struct ibmvnic_adapter *adapter)
@@ -3494,6 +3506,7 @@ static void ibmvnic_release_crq_queue(struct ibmvnic_adapter *adapter)
 
 	netdev_dbg(adapter->netdev, "Releasing CRQ\n");
 	free_irq(vdev->irq, adapter);
+	tasklet_kill(&adapter->tasklet);
 	do {
 		rc = plpar_hcall_norets(H_FREE_CRQ, vdev->unit_address);
 	} while (rc == H_BUSY || H_IS_LONG_BUSY(rc));
@@ -3539,6 +3552,9 @@ static int ibmvnic_init_crq_queue(struct ibmvnic_adapter *adapter)
 
 	retrc = 0;
 
+	tasklet_init(&adapter->tasklet, (void *)ibmvnic_tasklet,
+		     (unsigned long)adapter);
+
 	netdev_dbg(adapter->netdev, "registering irq 0x%x\n", vdev->irq);
 	rc = request_irq(vdev->irq, ibmvnic_interrupt, 0, IBMVNIC_NAME,
 			 adapter);
@@ -3560,6 +3576,7 @@ static int ibmvnic_init_crq_queue(struct ibmvnic_adapter *adapter)
 	return retrc;
 
 req_irq_failed:
+	tasklet_kill(&adapter->tasklet);
 	do {
 		rc = plpar_hcall_norets(H_FREE_CRQ, vdev->unit_address);
 	} while (rc == H_BUSY || H_IS_LONG_BUSY(rc));
diff --git a/drivers/net/ethernet/ibm/ibmvnic.h b/drivers/net/ethernet/ibm/ibmvnic.h
index dd775d9..0d0edc3 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.h
+++ b/drivers/net/ethernet/ibm/ibmvnic.h
@@ -1049,5 +1049,6 @@ struct ibmvnic_adapter {
 
 	struct work_struct vnic_crq_init;
 	struct work_struct ibmvnic_xport;
+	struct tasklet_struct tasklet;
 	bool failover;
 };
-- 
2.7.4