[SCSI] fcoe, libfc: fix an libfc issue with queue ramp down in libfc

The cmd_per_lun value is used by scsi-ml as fall back lowest
queue_depth value but in case of libfc cmd_per_lun is set to
same value as max queue_depth = 32.

So this patch reduces cmd_per_lun value to 3 and configures
each lun with default max queue_depth 32 in fc_slave_alloc.
Signed-off-by: Vasu Dev <vasu.dev@intel.com>
Acked-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

drivers/scsi/fcoe/fcoe.c

@@ -137,7 +137,7 @@ static struct scsi_host_template fcoe_shost_template = {
 	.change_queue_depth = fc_change_queue_depth,
 	.change_queue_type = fc_change_queue_type,
 	.this_id = -1,
-	.cmd_per_lun = 32,
+	.cmd_per_lun = 3,
 	.can_queue = FCOE_MAX_OUTSTANDING_COMMANDS,
 	.use_clustering = ENABLE_CLUSTERING,
 	.sg_tablesize = SG_ALL,

drivers/scsi/libfc/fc_fcp.c

@@ -2033,18 +2033,16 @@ EXPORT_SYMBOL(fc_eh_host_reset);
 int fc_slave_alloc(struct scsi_device *sdev)
 {
 	struct fc_rport *rport = starget_to_rport(scsi_target(sdev));
-	int queue_depth;
 
 	if (!rport || fc_remote_port_chkready(rport))
 		return -ENXIO;
 
-	if (sdev->tagged_supported) {
-		if (sdev->host->hostt->cmd_per_lun)
-			queue_depth = sdev->host->hostt->cmd_per_lun;
-		else
-			queue_depth = FC_FCP_DFLT_QUEUE_DEPTH;
-		scsi_activate_tcq(sdev, queue_depth);
-	}
+	if (sdev->tagged_supported)
+		scsi_activate_tcq(sdev, FC_FCP_DFLT_QUEUE_DEPTH);
+	else
+		scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev),
+					FC_FCP_DFLT_QUEUE_DEPTH);
+
 	return 0;
 }
 EXPORT_SYMBOL(fc_slave_alloc);