linux-kernel - [PATCH 06/13] ibmvfc: add handlers to drain and complete Sub-CRQ responses

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Message-Id: <20201126014824.123831-7-tyreld@linux.ibm.com>
Date:   Wed, 25 Nov 2020 19:48:17 -0600
From:   Tyrel Datwyler <tyreld@...ux.ibm.com>
To:     james.bottomley@...senpartnership.com
Cc:     martin.petersen@...cle.com, linux-scsi@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        brking@...ux.ibm.com, Tyrel Datwyler <tyreld@...ux.ibm.com>
Subject: [PATCH 06/13] 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.

Signed-off-by: Tyrel Datwyler <tyreld@...ux.ibm.com>
---
 drivers/scsi/ibmvscsi/ibmvfc.c | 72 ++++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)

diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c
index 6eaedda4917a..a8730522920e 100644
--- a/drivers/scsi/ibmvscsi/ibmvfc.c
+++ b/drivers/scsi/ibmvscsi/ibmvfc.c
@@ -3371,6 +3371,78 @@ 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);
+
+	switch (crq->valid) {
+	case IBMVFC_CRQ_CMD_RSP:
+		break;
+	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);
+	evt->done(evt);
+}
+
+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;
+	int done = 0;
+
+	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;
+	}
+}
+
 /**
  * ibmvfc_init_tgt - Set the next init job step for the target
  * @tgt:		ibmvfc target struct
-- 
2.27.0