From 039a08981a49e05f09db969cdd3f38f05a5df46f Mon Sep 17 00:00:00 2001 From: Brian King Date: Fri, 20 Mar 2009 15:44:35 -0500 Subject: [PATCH] [SCSI] ibmvfc: Fix dropped interrupts This patch fixes a problem of possible dropped interrupts. Currently, the ibmvfc driver has a race condition where after ibmvfc_interrupt gets run, the platform code clears the interrupt. This can result in lost interrupts and, in worst case scenarios, result in command timeouts. Fix this by implementing a tasklet similar to what the ibmvscsi driver does so that interrupt processing is no longer done in the actual interrupt handler, which eliminates the race. Signed-off-by: Brian King Signed-off-by: James Bottomley --- drivers/scsi/ibmvscsi/ibmvfc.c | 25 +++++++++++++++++++++++-- drivers/scsi/ibmvscsi/ibmvfc.h | 1 + 2 files changed, 24 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c index 93d1fbe4ee5..229e360f022 100644 --- a/drivers/scsi/ibmvscsi/ibmvfc.c +++ b/drivers/scsi/ibmvscsi/ibmvfc.c @@ -640,6 +640,7 @@ static void ibmvfc_release_crq_queue(struct ibmvfc_host *vhost) ibmvfc_dbg(vhost, "Releasing CRQ\n"); free_irq(vdev->irq, vhost); + tasklet_kill(&vhost->tasklet); do { rc = plpar_hcall_norets(H_FREE_CRQ, vdev->unit_address); } while (rc == H_BUSY || H_IS_LONG_BUSY(rc)); @@ -2699,6 +2700,25 @@ static struct ibmvfc_crq *ibmvfc_next_crq(struct ibmvfc_host *vhost) static irqreturn_t ibmvfc_interrupt(int irq, void *dev_instance) { struct ibmvfc_host *vhost = (struct ibmvfc_host *)dev_instance; + unsigned long flags; + + spin_lock_irqsave(vhost->host->host_lock, flags); + vio_disable_interrupts(to_vio_dev(vhost->dev)); + tasklet_schedule(&vhost->tasklet); + spin_unlock_irqrestore(vhost->host->host_lock, flags); + return IRQ_HANDLED; +} + +/** + * ibmvfc_tasklet - Interrupt handler tasklet + * @data: ibmvfc host struct + * + * Returns: + * Nothing + **/ +static void ibmvfc_tasklet(void *data) +{ + struct ibmvfc_host *vhost = data; struct vio_dev *vdev = to_vio_dev(vhost->dev); struct ibmvfc_crq *crq; struct ibmvfc_async_crq *async; @@ -2706,7 +2726,6 @@ static irqreturn_t ibmvfc_interrupt(int irq, void *dev_instance) int done = 0; spin_lock_irqsave(vhost->host->host_lock, flags); - vio_disable_interrupts(to_vio_dev(vhost->dev)); while (!done) { /* Pull all the valid messages off the CRQ */ while ((crq = ibmvfc_next_crq(vhost)) != NULL) { @@ -2734,7 +2753,6 @@ static irqreturn_t ibmvfc_interrupt(int irq, void *dev_instance) } spin_unlock_irqrestore(vhost->host->host_lock, flags); - return IRQ_HANDLED; } /** @@ -3859,6 +3877,8 @@ static int ibmvfc_init_crq(struct ibmvfc_host *vhost) retrc = 0; + tasklet_init(&vhost->tasklet, (void *)ibmvfc_tasklet, (unsigned long)vhost); + if ((rc = request_irq(vdev->irq, ibmvfc_interrupt, 0, IBMVFC_NAME, vhost))) { dev_err(dev, "Couldn't register irq 0x%x. rc=%d\n", vdev->irq, rc); goto req_irq_failed; @@ -3874,6 +3894,7 @@ static int ibmvfc_init_crq(struct ibmvfc_host *vhost) return retrc; req_irq_failed: + tasklet_kill(&vhost->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/scsi/ibmvscsi/ibmvfc.h b/drivers/scsi/ibmvscsi/ibmvfc.h index b21e071b986..70107522e3a 100644 --- a/drivers/scsi/ibmvscsi/ibmvfc.h +++ b/drivers/scsi/ibmvscsi/ibmvfc.h @@ -684,6 +684,7 @@ struct ibmvfc_host { char partition_name[97]; void (*job_step) (struct ibmvfc_host *); struct task_struct *work_thread; + struct tasklet_struct tasklet; wait_queue_head_t init_wait_q; wait_queue_head_t work_wait_q; }; -- 2.41.1