[SCSI] qla2xxx: Set host can_queue value based on available resources.

Tell the mid-layer that number of commands we can queue is the available
resources we have minus a small amount for internal commands.

Signed-off-by: Chad Dupuis <chad.dupuis@qlogic.com>
Signed-off-by: Saurav Kashyap <saurav.kashyap@qlogic.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/qla2xxx/qla_os.c

@@ -2561,10 +2561,6 @@ qla2x00_probe_one(struct pci_dev *pdev, const struct pci_device_id *id)
 
 	host = base_vha->host;
 	base_vha->req = req;
-	if (IS_QLAFX00(ha))
-		host->can_queue = QLAFX00_MAX_CANQUEUE;
-	else
-		host->can_queue = req->length + 128;
 	if (IS_QLA2XXX_MIDTYPE(ha))
 		base_vha->mgmt_svr_loop_id = 10 + base_vha->vp_idx;
 	else
@@ -2587,11 +2583,6 @@ qla2x00_probe_one(struct pci_dev *pdev, const struct pci_device_id *id)
 		if (!IS_QLA82XX(ha))
 			host->sg_tablesize = QLA_SG_ALL;
 	}
-	ql_dbg(ql_dbg_init, base_vha, 0x0032,
-	    "can_queue=%d, req=%p, "
-	    "mgmt_svr_loop_id=%d, sg_tablesize=%d.\n",
-	    host->can_queue, base_vha->req,
-	    base_vha->mgmt_svr_loop_id, host->sg_tablesize);
 	host->max_id = ha->max_fibre_devices;
 	host->cmd_per_lun = 3;
 	host->unique_id = host->host_no;
@@ -2707,6 +2698,16 @@ qla2x00_probe_one(struct pci_dev *pdev, const struct pci_device_id *id)
 		goto probe_failed;
 	}
 
+	if (IS_QLAFX00(ha))
+		host->can_queue = QLAFX00_MAX_CANQUEUE;
+	else
+		host->can_queue = req->num_outstanding_cmds - 10;
+
+	ql_dbg(ql_dbg_init, base_vha, 0x0032,
+	    "can_queue=%d, req=%p, mgmt_svr_loop_id=%d, sg_tablesize=%d.\n",
+	    host->can_queue, base_vha->req,
+	    base_vha->mgmt_svr_loop_id, host->sg_tablesize);
+
 	if (ha->mqenable) {
 		if (qla25xx_setup_mode(base_vha)) {
 			ql_log(ql_log_warn, base_vha, 0x00ec,