diff --git a/drivers/usb/serial/digi_acceleport.c b/drivers/usb/serial/digi_acceleport.c
index ae410c4678ea..5f9c6e46bee5 100644
--- a/drivers/usb/serial/digi_acceleport.c
+++ b/drivers/usb/serial/digi_acceleport.c
@@ -1405,19 +1405,19 @@ static void digi_close(struct usb_serial_port *port, struct file *filp)
 	unsigned char buf[32];
 	struct tty_struct *tty = port->tty;
 	struct digi_port *priv = usb_get_serial_port_data(port);
-	unsigned long flags = 0;
 
 	dbg("digi_close: TOP: port=%d, open_count=%d",
 		priv->dp_port_num, port->open_count);
 
+	mutex_lock(&port->serial->disc_mutex);
 	/* if disconnected, just clear flags */
-	if (!usb_get_intfdata(port->serial->interface))
+	if (port->serial->disconnected)
 		goto exit;
 
 	/* do cleanup only after final close on this port */
-	spin_lock_irqsave(&priv->dp_port_lock, flags);
+	spin_lock_irq(&priv->dp_port_lock);
 	priv->dp_in_close = 1;
-	spin_unlock_irqrestore(&priv->dp_port_lock, flags);
+	spin_unlock_irq(&priv->dp_port_lock);
 
 	/* tell line discipline to process only XON/XOFF */
 	tty->closing = 1;
@@ -1482,11 +1482,12 @@ static void digi_close(struct usb_serial_port *port, struct file *filp)
 	}
 	tty->closing = 0;
 exit:
-	spin_lock_irqsave(&priv->dp_port_lock, flags);
+	spin_lock_irq(&priv->dp_port_lock);
 	priv->dp_write_urb_in_use = 0;
 	priv->dp_in_close = 0;
 	wake_up_interruptible(&priv->dp_close_wait);
-	spin_unlock_irqrestore(&priv->dp_port_lock, flags);
+	spin_unlock_irq(&priv->dp_port_lock);
+	mutex_unlock(&port->serial->disc_mutex);
 	dbg("digi_close: done");
 }
 
diff --git a/drivers/usb/serial/oti6858.c b/drivers/usb/serial/oti6858.c
index db725aaf7d19..a3847d6c946e 100644
--- a/drivers/usb/serial/oti6858.c
+++ b/drivers/usb/serial/oti6858.c
@@ -649,7 +649,7 @@ static void oti6858_close(struct usb_serial_port *port, struct file *filp)
 		set_current_state(TASK_INTERRUPTIBLE);
 		if (oti6858_buf_data_avail(priv->buf) == 0
 		|| timeout == 0 || signal_pending(current)
-		|| !usb_get_intfdata(port->serial->interface))	/* disconnect */
+		|| port->serial->disconnected)
 			break;
 		spin_unlock_irqrestore(&priv->lock, flags);
 		timeout = schedule_timeout(timeout);
diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c
index ac3d8765f482..ae3ec1a64008 100644
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -667,7 +667,7 @@ static void pl2303_close(struct usb_serial_port *port, struct file *filp)
 		set_current_state(TASK_INTERRUPTIBLE);
 		if (pl2303_buf_data_avail(priv->buf) == 0 ||
 		    timeout == 0 || signal_pending(current) ||
-		    !usb_get_intfdata(port->serial->interface))	/* disconnect */
+		    port->serial->disconnected)
 			break;
 		spin_unlock_irqrestore(&priv->lock, flags);
 		timeout = schedule_timeout(timeout);
diff --git a/drivers/usb/serial/ti_usb_3410_5052.c b/drivers/usb/serial/ti_usb_3410_5052.c
index 70f56c8aef99..b517f93352ec 100644
--- a/drivers/usb/serial/ti_usb_3410_5052.c
+++ b/drivers/usb/serial/ti_usb_3410_5052.c
@@ -1493,11 +1493,10 @@ static void ti_drain(struct ti_port *tport, unsigned long timeout, int flush)
 	struct ti_device *tdev = tport->tp_tdev;
 	struct usb_serial_port *port = tport->tp_port;
 	wait_queue_t wait;
-	unsigned long flags;
 
 	dbg("%s - port %d", __FUNCTION__, port->number);
 
-	spin_lock_irqsave(&tport->tp_lock, flags);
+	spin_lock_irq(&tport->tp_lock);
 
 	/* wait for data to drain from the buffer */
 	tdev->td_urb_error = 0;
@@ -1508,11 +1507,11 @@ static void ti_drain(struct ti_port *tport, unsigned long timeout, int flush)
 		if (ti_buf_data_avail(tport->tp_write_buf) == 0
 		|| timeout == 0 || signal_pending(current)
 		|| tdev->td_urb_error
-		|| !usb_get_intfdata(port->serial->interface))  /* disconnect */
+		|| port->serial->disconnected)  /* disconnect */
 			break;
-		spin_unlock_irqrestore(&tport->tp_lock, flags);
+		spin_unlock_irq(&tport->tp_lock);
 		timeout = schedule_timeout(timeout);
-		spin_lock_irqsave(&tport->tp_lock, flags);
+		spin_lock_irq(&tport->tp_lock);
 	}
 	set_current_state(TASK_RUNNING);
 	remove_wait_queue(&tport->tp_write_wait, &wait);
@@ -1521,19 +1520,23 @@ static void ti_drain(struct ti_port *tport, unsigned long timeout, int flush)
 	if (flush)
 		ti_buf_clear(tport->tp_write_buf);
 
-	spin_unlock_irqrestore(&tport->tp_lock, flags);
+	spin_unlock_irq(&tport->tp_lock);
 
+	mutex_lock(&port->serial->disc_mutex);
 	/* wait for data to drain from the device */
 	/* wait for empty tx register, plus 20 ms */
 	timeout += jiffies;
 	tport->tp_lsr &= ~TI_LSR_TX_EMPTY;
 	while ((long)(jiffies - timeout) < 0 && !signal_pending(current)
 	&& !(tport->tp_lsr&TI_LSR_TX_EMPTY) && !tdev->td_urb_error
-	&& usb_get_intfdata(port->serial->interface)) {  /* not disconnected */
+	&& !port->serial->disconnected) {
 		if (ti_get_lsr(tport))
 			break;
+		mutex_unlock(&port->serial->disc_mutex);
 		msleep_interruptible(20);
+		mutex_lock(&port->serial->disc_mutex);
 	}
+	mutex_unlock(&port->serial->disc_mutex);
 }