USB: more serial drivers writing after disconnect

this covers the rest of the obvious cases by using the flags
and locks to guard against disconnect which were introduced
in the earlier patch against mos7720.

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

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index 2c142bb04fe1..90dcc625f70d 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -1198,7 +1198,8 @@ static void ftdi_close (struct usb_serial_port *port, struct file *filp)
 
         dbg("%s", __FUNCTION__);
 
-        if (c_cflag & HUPCL){
+        mutex_lock(&port->serial->disc_mutex);
+        if (c_cflag & HUPCL && !port->serial->disconnected){
                 /* Disable flow control */
                 if (usb_control_msg(port->serial->dev,
                                     usb_sndctrlpipe(port->serial->dev, 0),
@@ -1212,6 +1213,7 @@ static void ftdi_close (struct usb_serial_port *port, struct file *filp)
                 /* drop RTS and DTR */
                 clear_mctrl(port, TIOCM_DTR | TIOCM_RTS);
         } /* Note change no line if hupcl is off */
+        mutex_unlock(&port->serial->disc_mutex);
 
         /* cancel any scheduled reading */
         cancel_delayed_work(&priv->rx_work);