[SCSI] fnic: fnic Driver Tuneables Exposed through CLI

Introduced module params to provide dynamic way of configuring
queue depth.

Added support to get max io throttle count through UCSM to
configure maximum outstanding IOs supported by fnic and push
that value to scsi mid-layer.

  Supported IO throttle values:

  UCSM IO THROTTLE VALUE        FNIC MAX OUTSTANDING IOS
  ------------------------------------------------------
        16 (Default)                    2048
        <= 256                          256
        > 256                           <ucsm value>

Signed-off-by: Hiral Patel <hiralpat@cisco.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 21 insertions, 8 deletions

diff --git a/drivers/scsi/fnic/fnic_main.c b/drivers/scsi/fnic/fnic_main.c
index 835a9cdbac8b..bbf81ea3a252 100644
--- a/drivers/scsi/fnic/fnic_main.c
+++ b/drivers/scsi/fnic/fnic_main.c
@@ -74,6 +74,10 @@ module_param(fnic_trace_max_pages, uint, S_IRUGO|S_IWUSR);
 MODULE_PARM_DESC(fnic_trace_max_pages, "Total allocated memory pages "
 					"for fnic trace buffer");
 
+static unsigned int fnic_max_qdepth = FNIC_DFLT_QUEUE_DEPTH;
+module_param(fnic_max_qdepth, uint, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(fnic_max_qdepth, "Queue depth to report for each LUN");
+
 static struct libfc_function_template fnic_transport_template = {
 	.frame_send = fnic_send,
 	.lport_set_port_id = fnic_set_port_id,
@@ -91,7 +95,7 @@ static int fnic_slave_alloc(struct scsi_device *sdev)
 	if (!rport || fc_remote_port_chkready(rport))
 		return -ENXIO;
 
-	scsi_activate_tcq(sdev, FNIC_DFLT_QUEUE_DEPTH);
+	scsi_activate_tcq(sdev, fnic_max_qdepth);
 	return 0;
 }
 
@@ -552,13 +556,6 @@ static int fnic_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 	host->transportt = fnic_fc_transport;
 
-	err = scsi_init_shared_tag_map(host, FNIC_MAX_IO_REQ);
-	if (err) {
-		shost_printk(KERN_ERR, fnic->lport->host,
-			     "Unable to alloc shared tag map\n");
-		goto err_out_free_hba;
-	}
-
 	/* Setup PCI resources */
 	pci_set_drvdata(pdev, fnic);
 
@@ -671,6 +668,22 @@ static int fnic_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 			     "aborting.\n");
 		goto err_out_dev_close;
 	}
+
+	/* Configure Maximum Outstanding IO reqs*/
+	if (fnic->config.io_throttle_count != FNIC_UCSM_DFLT_THROTTLE_CNT_BLD) {
+		host->can_queue = min_t(u32, FNIC_MAX_IO_REQ,
+					max_t(u32, FNIC_MIN_IO_REQ,
+					fnic->config.io_throttle_count));
+	}
+	fnic->fnic_max_tag_id = host->can_queue;
+
+	err = scsi_init_shared_tag_map(host, fnic->fnic_max_tag_id);
+	if (err) {
+		shost_printk(KERN_ERR, fnic->lport->host,
+			  "Unable to alloc shared tag map\n");
+		goto err_out_dev_close;
+	}
+
 	host->max_lun = fnic->config.luns_per_tgt;
 	host->max_id = FNIC_MAX_FCP_TARGET;
 	host->max_cmd_len = FCOE_MAX_CMD_LEN;