mei: mei_irq_thread_write_handler check for overflow

check for overflow when retrieving empty write slots

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/interrupt.c

@@ -1204,6 +1204,9 @@ static int mei_irq_thread_write_handler(struct mei_io_list *cmpl_list,
 		return 0;
 	}
 	*slots = mei_count_empty_write_slots(dev);
+	if (*slots <= 0)
+		return -EMSGSIZE;
+
 	/* complete all waiting for write CB */
 	dev_dbg(&dev->pdev->dev, "complete all waiting for write cb.\n");