On 11/27/20 9:46 AM, Brian King wrote:

On 11/25/20 7:48 PM, Tyrel Datwyler wrote:

quoted

Allocate a set of Sub-CRQs in advance. During channel setup the client
and VIOS negotiate the number of queues the VIOS supports and the number
that the client desires to request. Its possible that the final channel
resources allocated is less than requested, but the client is still
responsible for sending handles for every queue it is hoping for.

Also, provide deallocation cleanup routines.

Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
---
 drivers/scsi/ibmvscsi/ibmvfc.c | 115 +++++++++++++++++++++++++++++++++
 drivers/scsi/ibmvscsi/ibmvfc.h |   1 +
 2 files changed, 116 insertions(+)

diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c
index 260b82e3cc01..571abdb48384 100644
--- a/drivers/scsi/ibmvscsi/ibmvfc.c
+++ b/drivers/scsi/ibmvscsi/ibmvfc.c

@@ -4983,6 +4983,114 @@ static int ibmvfc_init_crq(struct ibmvfc_host *vhost)
 	return retrc;
 }
 
+static int ibmvfc_register_scsi_channel(struct ibmvfc_host *vhost,
+				  int index)
+{
+	struct device *dev = vhost->dev;
+	struct vio_dev *vdev = to_vio_dev(dev);
+	struct ibmvfc_sub_queue *scrq = &vhost->scsi_scrqs.scrqs[index];
+	int rc = -ENOMEM;
+
+	ENTER;
+
+	scrq->msgs = (struct ibmvfc_sub_crq *)get_zeroed_page(GFP_KERNEL);
+	if (!scrq->msgs)
+		return rc;
+
+	scrq->size = PAGE_SIZE / sizeof(*scrq->msgs);
+	scrq->msg_token = dma_map_single(dev, scrq->msgs, PAGE_SIZE,
+					 DMA_BIDIRECTIONAL);
+
+	if (dma_mapping_error(dev, scrq->msg_token))
+		goto dma_map_failed;
+
+	rc = h_reg_sub_crq(vdev->unit_address, scrq->msg_token, PAGE_SIZE,
+			   &scrq->cookie, &scrq->hw_irq);
+
+	if (rc) {
+		dev_warn(dev, "Error registering sub-crq: %d\n", rc);
+		dev_warn(dev, "Firmware may not support MQ\n");
+		goto reg_failed;
+	}
+
+	scrq->hwq_id = index;
+	scrq->vhost = vhost;
+
+	LEAVE;
+	return 0;
+
+reg_failed:
+	dma_unmap_single(dev, scrq->msg_token, PAGE_SIZE, DMA_BIDIRECTIONAL);
+dma_map_failed:
+	free_page((unsigned long)scrq->msgs);
+	LEAVE;
+	return rc;
+}
+
+static void ibmvfc_deregister_scsi_channel(struct ibmvfc_host *vhost, int index)
+{
+	struct device *dev = vhost->dev;
+	struct vio_dev *vdev = to_vio_dev(dev);
+	struct ibmvfc_sub_queue *scrq = &vhost->scsi_scrqs.scrqs[index];
+	long rc;
+
+	ENTER;
+
+	do {
+		rc = plpar_hcall_norets(H_FREE_SUB_CRQ, vdev->unit_address,
+					scrq->cookie);
+	} while (rc == H_BUSY || H_IS_LONG_BUSY(rc));
+
+	if (rc)
+		dev_err(dev, "Failed to free sub-crq[%d]: rc=%ld\n", index, rc);
+
+	dma_unmap_single(dev, scrq->msg_token, PAGE_SIZE, DMA_BIDIRECTIONAL);
+	free_page((unsigned long)scrq->msgs);
+	LEAVE;
+}
+
+static int ibmvfc_init_sub_crqs(struct ibmvfc_host *vhost)
+{
+	int i, j;
+
+	ENTER;
+
+	vhost->scsi_scrqs.scrqs = kcalloc(vhost->client_scsi_channels,
+					  sizeof(*vhost->scsi_scrqs.scrqs),
+					  GFP_KERNEL);
+	if (!vhost->scsi_scrqs.scrqs)
+		return -1;
+
+	for (i = 0; i < vhost->client_scsi_channels; i++) {
+		if (ibmvfc_register_scsi_channel(vhost, i)) {
+			for (j = i; j > 0; j--)
+				ibmvfc_deregister_scsi_channel(vhost, j - 1);
+			kfree(vhost->scsi_scrqs.scrqs);
+			LEAVE;
+			return -1;
+		}
+	}
+
+	LEAVE;
+	return 0;
+}
+
+static void ibmvfc_release_sub_crqs(struct ibmvfc_host *vhost)
+{
+	int i;
+
+	ENTER;
+	if (!vhost->scsi_scrqs.scrqs)
+		return;
+
+	for (i = 0; i < vhost->client_scsi_channels; i++)
+		ibmvfc_deregister_scsi_channel(vhost, i);
+
+	vhost->scsi_scrqs.active_queues = 0;
+	kfree(vhost->scsi_scrqs.scrqs);

Do you want to NULL this out after you free it do you don't keep
a reference to a freed page around?

This isn't actually a page, but a dynamically allocated array of
ibmvfc_sub_queues, but it should be NULL'ed regardless.

-Tyrel

quoted

+	LEAVE;
+}
+
 /**
  * ibmvfc_free_mem - Free memory for vhost
  * @vhost:	ibmvfc host struct