[SCSI] fnic: Kernel panic while running sh/nosh with max lun cfg

Kernel panics due to NULL lport while executing the log message because
of synchronization issues between libfc and scsi transport fc. Checking
for NULL pointers at the beginning of this routine would resolve the issue
from kernel panic point of view.

Signed-off-by: Sesidhar Baddel <[e-mail]>
Signed-off-by: Hiral Patel <[e-mail]>
Signed-off-by: James Bottomley <[e-mail]>

drivers/scsi/fnic/fnic_scsi.c

···
 	unsigned long flags;
 	struct scsi_cmnd *sc;
 	struct scsi_lun fc_lun;
-	struct fc_rport_libfc_priv *rdata = rport->dd_data;
-	struct fc_lport *lport = rdata->local_port;
-	struct fnic *fnic = lport_priv(lport);
+	struct fc_rport_libfc_priv *rdata;
+	struct fc_lport *lport;
+	struct fnic *fnic;
 	struct fc_rport *cmd_rport;
 	enum fnic_ioreq_state old_ioreq_state;
 
+	if (!rport) {
+		printk(KERN_ERR "fnic_terminate_rport_io: rport is NULL\n");
+		return;
+	}
+	rdata = rport->dd_data;
+
+	if (!rdata) {
+		printk(KERN_ERR "fnic_terminate_rport_io: rdata is NULL\n");
+		return;
+	}
+	lport = rdata->local_port;
+
+	if (!lport) {
+		printk(KERN_ERR "fnic_terminate_rport_io: lport is NULL\n");
+		return;
+	}
+	fnic = lport_priv(lport);
 	FNIC_SCSI_DBG(KERN_DEBUG,
 		      fnic->lport->host, "fnic_terminate_rport_io called"
 		      " wwpn 0x%llx, wwnn0x%llx, rport 0x%p, portid 0x%06x\n",