USB: visor: fix trivial accounting bug in visor driver

usb:usbserial:visor: fix accounting in error case

data not pushed to the tty layer due to an error mustn't be counted

Signed-off-by: Oliver Neukum <oliver@neukum.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/usb/serial/visor.c b/drivers/usb/serial/visor.c
index 1aa5d20a5d99..8e2d6dd9add0 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);