USB: serial: cyberjack: use irqsave() in USB's complete callback

The USB completion callback does not disable interrupts while acquiring
the lock. We want to remove the local_irq_disable() invocation from
__usb_hcd_giveback_urb() and therefore it is required for the callback
handler to disable the interrupts while acquiring the lock.
The callback may be invoked either in IRQ or BH context depending on the
USB host controller.
Use the _irqsave() variant of the locking primitives.

Signed-off-by: John Ogness <[e-mail]>
Signed-off-by: Sebastian Andrzej Siewior <[e-mail]>
Signed-off-by: Johan Hovold <[e-mail]>

drivers/usb/serial/cyberjack.c

···
 	struct device *dev = &port->dev;
 	unsigned char *data = urb->transfer_buffer;
 	int status = urb->status;
+	unsigned long flags;
 	int result;
 
 	/* the urb might have been killed. */
···
 		/* This is a announcement of coming bulk_ins. */
 		unsigned short size = ((unsigned short)data[3]<<8)+data[2]+3;
 
-		spin_lock(&priv->lock);
+		spin_lock_irqsave(&priv->lock, flags);
 
 		old_rdtodo = priv->rdtodo;
 
 		if (old_rdtodo > SHRT_MAX - size) {
 			dev_dbg(dev, "To many bulk_in urbs to do.\n");
-			spin_unlock(&priv->lock);
+			spin_unlock_irqrestore(&priv->lock, flags);
 			goto resubmit;
 		}
 
···
 
 		dev_dbg(dev, "%s - rdtodo: %d\n", __func__, priv->rdtodo);
 
-		spin_unlock(&priv->lock);
+		spin_unlock_irqrestore(&priv->lock, flags);
 
 		if (!old_rdtodo) {
 			result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
···
 	struct cyberjack_private *priv = usb_get_serial_port_data(port);
 	struct device *dev = &port->dev;
 	unsigned char *data = urb->transfer_buffer;
+	unsigned long flags;
 	short todo;
 	int result;
 	int status = urb->status;
···
 		tty_flip_buffer_push(&port->port);
 	}
 
-	spin_lock(&priv->lock);
+	spin_lock_irqsave(&priv->lock, flags);
 
 	/* Reduce urbs to do by one. */
 	priv->rdtodo -= urb->actual_length;
···
 		priv->rdtodo = 0;
 	todo = priv->rdtodo;
 
-	spin_unlock(&priv->lock);
+	spin_unlock_irqrestore(&priv->lock, flags);
 
 	dev_dbg(dev, "%s - rdtodo: %d\n", __func__, todo);
 
···
 	struct cyberjack_private *priv = usb_get_serial_port_data(port);
 	struct device *dev = &port->dev;
 	int status = urb->status;
+	unsigned long flags;
 
 	set_bit(0, &port->write_urbs_free);
 	if (status) {
···
 		return;
 	}
 
-	spin_lock(&priv->lock);
+	spin_lock_irqsave(&priv->lock, flags);
 
 	/* only do something if we have more data to send */
 	if (priv->wrfilled) {
···
 	}
 
 exit:
-	spin_unlock(&priv->lock);
+	spin_unlock_irqrestore(&priv->lock, flags);
 	usb_serial_port_softint(port);
 }