1 files changed, 15 insertions, 13 deletions

diff --git a/drivers/usb/serial/visor.c b/drivers/usb/serial/visor.c
index 1aa5d20a5d99..ad1f9232292d 100644
--- a/drivers/usb/serial/visor.c
+++ b/drivers/usb/serial/visor.c
@@ -513,7 +513,8 @@ static void visor_read_bulk_callback(struct urb *urb)
                         tty_kref_put(tty);
                 }
                 spin_lock(&priv->lock);
-                priv->bytes_in += available_room;
+                if (tty)
+                        priv->bytes_in += available_room;
 
         } else {
                 spin_lock(&priv->lock);
@@ -582,12 +583,11 @@ static void visor_throttle(struct tty_struct *tty)
 {
         struct usb_serial_port *port = tty->driver_data;
         struct visor_private *priv = usb_get_serial_port_data(port);
-        unsigned long flags;
 
         dbg("%s - port %d", __func__, port->number);
-        spin_lock_irqsave(&priv->lock, flags);
+        spin_lock_irq(&priv->lock);
         priv->throttled = 1;
-        spin_unlock_irqrestore(&priv->lock, flags);
+        spin_unlock_irq(&priv->lock);
 }
 
 
@@ -595,21 +595,23 @@ static void visor_unthrottle(struct tty_struct *tty)
 {
         struct usb_serial_port *port = tty->driver_data;
         struct visor_private *priv = usb_get_serial_port_data(port);
-        unsigned long flags;
-        int result;
+        int result, was_throttled;
 
         dbg("%s - port %d", __func__, port->number);
-        spin_lock_irqsave(&priv->lock, flags);
+        spin_lock_irq(&priv->lock);
         priv->throttled = 0;
+        was_throttled = priv->actually_throttled;
         priv->actually_throttled = 0;
-        spin_unlock_irqrestore(&priv->lock, flags);
+        spin_unlock_irq(&priv->lock);
 
-        port->read_urb->dev = port->serial->dev;
-        result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
-        if (result)
-                dev_err(&port->dev,
-                        "%s - failed submitting read urb, error %d\n",
+        if (was_throttled) {
+                port->read_urb->dev = port->serial->dev;
+                result = usb_submit_urb(port->read_urb, GFP_KERNEL);
+                if (result)
+                        dev_err(&port->dev,
+                                "%s - failed submitting read urb, error %d\n",
                                                         __func__, result);
+        }
 }
 
 static int palm_os_3_probe(struct usb_serial *serial,