Re: [PATCH v3 06/18] ibmvfc: add handlers to drain and complete Sub-CRQ responses

Tyrel Datwyler
2020-12-05T00:17:50Z

On 12/4/20 6:51 AM, Brian King wrote:
> On 12/2/20 8:07 PM, Tyrel Datwyler wrote:
>> The logic for iterating over the Sub-CRQ responses is similiar to that
>> of the primary CRQ. Add the necessary handlers for processing those
>> responses.
>>
>> Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
>> ---
>> drivers/scsi/ibmvscsi/ibmvfc.c | 80 ++++++++++++++++++++++++++++++++++
>> 1 file changed, 80 insertions(+)
>>
>> diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c
>> index e082935f56cf..b61ae1df21e5 100644
>> --- a/drivers/scsi/ibmvscsi/ibmvfc.c
>> +++ b/drivers/scsi/ibmvscsi/ibmvfc.c
>> @@ -3381,6 +3381,86 @@ static int ibmvfc_toggle_scrq_irq(struct ibmvfc_sub_queue *scrq, int enable)
>> return rc;
>> }
>>
>> +static void ibmvfc_handle_scrq(struct ibmvfc_crq *crq, struct ibmvfc_host *vhost)
>> +{
>> + struct ibmvfc_event *evt = (struct ibmvfc_event *)be64_to_cpu(crq->ioba);
>> + unsigned long flags;
>> +
>> + switch (crq->valid) {
>> + case IBMVFC_CRQ_CMD_RSP:
>> + break;
>> + case IBMVFC_CRQ_XPORT_EVENT:
>> + return;
>> + default:
>> + dev_err(vhost->dev, "Got and invalid message type 0x%02x\n", crq->valid);
>> + return;
>> + }
>> +
>> + /* The only kind of payload CRQs we should get are responses to
>> + * things we send. Make sure this response is to something we
>> + * actually sent
>> + */
>> + if (unlikely(!ibmvfc_valid_event(&vhost->pool, evt))) {
>> + dev_err(vhost->dev, "Returned correlation_token 0x%08llx is invalid!\n",
>> + crq->ioba);
>> + return;
>> + }
>> +
>> + if (unlikely(atomic_read(&evt->free))) {
>> + dev_err(vhost->dev, "Received duplicate correlation_token 0x%08llx!\n",
>> + crq->ioba);
>> + return;
>> + }
>> +
>> + del_timer(&evt->timer);
>> + list_del(&evt->queue);
>> + ibmvfc_trc_end(evt);> + spin_unlock_irqrestore(vhost->host->host_lock, flags);
>
> You can't do this here... You are grabbing the host lock in ibmvfc_drain_sub_crq
> and saving the irqflags to a local in that function, then doing a spin_unlock_irqrestore
> and restoring irqflags using an uninitialized local in this function...
>
> I'm assuming this will get sorted out with the locking changes we've been discussing off-list...

Correct, moving to per-queue locks and flags stored in the queue struct.

-Tyrel

>
>
>> + evt->done(evt);
>> + spin_lock_irqsave(vhost->host->host_lock, flags);
>> +}
>> +
>> +static struct ibmvfc_crq *ibmvfc_next_scrq(struct ibmvfc_sub_queue *scrq)
>> +{
>> + struct ibmvfc_crq *crq;
>> +
>> + crq = &scrq->msgs[scrq->cur].crq;
>> + if (crq->valid & 0x80) {
>> + if (++scrq->cur == scrq->size)
>> + scrq->cur = 0;
>> + rmb();
>> + } else
>> + crq = NULL;
>> +
>> + return crq;
>> +}
>> +
>> +static void ibmvfc_drain_sub_crq(struct ibmvfc_sub_queue *scrq)
>> +{
>> + struct ibmvfc_crq *crq;
>> + unsigned long flags;
>> + int done = 0;
>> +
>> + spin_lock_irqsave(scrq->vhost->host->host_lock, flags);
>> + while (!done) {
>> + while ((crq = ibmvfc_next_scrq(scrq)) != NULL) {
>> + ibmvfc_handle_scrq(crq, scrq->vhost);
>> + crq->valid = 0;
>> + wmb();
>> + }
>> +
>> + ibmvfc_toggle_scrq_irq(scrq, 1);
>> + if ((crq = ibmvfc_next_scrq(scrq)) != NULL) {
>> + ibmvfc_toggle_scrq_irq(scrq, 0);
>> + ibmvfc_handle_scrq(crq, scrq->vhost);
>> + crq->valid = 0;
>> + wmb();
>> + } else
>> + done = 1;
>> + }
>> + spin_unlock_irqrestore(scrq->vhost->host->host_lock, flags);
>> +}
>> +
>> /**
>> * ibmvfc_init_tgt - Set the next init job step for the target
>> * @tgt: ibmvfc target struct
>>
>
>