scsi: ibmvfc: Add handlers to drain and complete Sub-CRQ responses

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.

Link: https://lore.kernel.org/r/20210114203148.246656-10-tyreld@linux.ibm.com
Reviewed-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ibmvscsi/ibmvfc.c

@@ -3485,6 +3485,92 @@ static int ibmvfc_toggle_scrq_irq(struct ibmvfc_queue *scrq, int enable)
 	return rc;
 }
 
+static void ibmvfc_handle_scrq(struct ibmvfc_crq *crq, struct ibmvfc_host *vhost,
+			       struct list_head *evt_doneq)
+{
+	struct ibmvfc_event *evt = (struct ibmvfc_event *)be64_to_cpu(crq->ioba);
+
+	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(&evt->queue->evt_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;
+	}
+
+	spin_lock(&evt->queue->l_lock);
+	list_move_tail(&evt->queue_list, evt_doneq);
+	spin_unlock(&evt->queue->l_lock);
+}
+
+static struct ibmvfc_crq *ibmvfc_next_scrq(struct ibmvfc_queue *scrq)
+{
+	struct ibmvfc_crq *crq;
+
+	crq = &scrq->msgs.scrq[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_queue *scrq)
+{
+	struct ibmvfc_crq *crq;
+	struct ibmvfc_event *evt, *temp;
+	unsigned long flags;
+	int done = 0;
+	LIST_HEAD(evt_doneq);
+
+	spin_lock_irqsave(scrq->q_lock, flags);
+	while (!done) {
+		while ((crq = ibmvfc_next_scrq(scrq)) != NULL) {
+			ibmvfc_handle_scrq(crq, scrq->vhost, &evt_doneq);
+			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, &evt_doneq);
+			crq->valid = 0;
+			wmb();
+		} else
+			done = 1;
+	}
+	spin_unlock_irqrestore(scrq->q_lock, flags);
+
+	list_for_each_entry_safe(evt, temp, &evt_doneq, queue_list) {
+		del_timer(&evt->timer);
+		list_del(&evt->queue_list);
+		ibmvfc_trc_end(evt);
+		evt->done(evt);
+	}
+}
+
 /**
  * ibmvfc_init_tgt - Set the next init job step for the target
  * @tgt:		ibmvfc target struct