USB: make sure usb serial drivers don't flush to logically disconnected devices

[safe/jmp/linux-2.6] / drivers / usb / serial / mct_u232.c

diff --git a/drivers/usb/serial/mct_u232.c b/drivers/usb/serial/mct_u232.c
index 88b2074..fc1cea4 100644 (file)
--- a/drivers/usb/serial/mct_u232.c
+++ b/drivers/usb/serial/mct_u232.c
@@ -487,21 +487,22 @@ error:
 static void mct_u232_close (struct usb_serial_port *port, struct file *filp)
 {
        unsigned int c_cflag;
-       unsigned long flags;
        unsigned int control_state;
        struct mct_u232_private *priv = usb_get_serial_port_data(port);
        dbg("%s port %d", __FUNCTION__, port->number);
 
        if (port->tty) {
                c_cflag = port->tty->termios->c_cflag;
-               if (c_cflag & HUPCL) {
-                  /* drop DTR and RTS */
-                  spin_lock_irqsave(&priv->lock, flags);
-                  priv->control_state &= ~(TIOCM_DTR | TIOCM_RTS);
-                  control_state = priv->control_state;
-                  spin_unlock_irqrestore(&priv->lock, flags);
-                  mct_u232_set_modem_ctrl(port->serial, control_state);
+               mutex_lock(&port->serial->disc_mutex);
+               if (c_cflag & HUPCL && !port->serial->disconnected) {
+                       /* drop DTR and RTS */
+                       spin_lock_irq(&priv->lock);
+                       priv->control_state &= ~(TIOCM_DTR | TIOCM_RTS);
+                       control_state = priv->control_state;
+                       spin_unlock_irq(&priv->lock);
+                       mct_u232_set_modem_ctrl(port->serial, control_state);
                }
+               mutex_unlock(&port->serial->disc_mutex);
        }