USB: ch341: fix TIOCMIWAIT and disconnect

Use tty-port modem-status-change wait queue on which processes are woken
up at hangup and disconnect.

Currently a process waiting on modem-status changes will not be woken on
device disconnect as wake up was only done in dtr_rts which isn't
guaranteed to be called (e.g. if HUPCL is not set).

Also remove the redundant wake-up call from dtr_rts.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 2 insertions, 3 deletions

diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index 1a97985df782..c2a4171ab9cb 100644
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -296,7 +296,6 @@ static void ch341_dtr_rts(struct usb_serial_port *port, int on)
                 priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
         spin_unlock_irqrestore(&priv->lock, flags);
         ch341_set_handshake(port->serial->dev, priv->line_control);
-        wake_up_interruptible(&port->delta_msr_wait);
 }
 
 static void ch341_close(struct usb_serial_port *port)
@@ -489,7 +488,7 @@ static void ch341_read_int_callback(struct urb *urb)
                         tty_kref_put(tty);
                 }
 
-                wake_up_interruptible(&port->delta_msr_wait);
+                wake_up_interruptible(&port->port.delta_msr_wait);
         }
 
 exit:
@@ -516,7 +515,7 @@ static int ch341_tiocmiwait(struct tty_struct *tty, unsigned long arg)
         spin_unlock_irqrestore(&priv->lock, flags);
 
         while (!multi_change) {
-                interruptible_sleep_on(&port->delta_msr_wait);
+                interruptible_sleep_on(&port->port.delta_msr_wait);
                 /* see if a signal did it */
                 if (signal_pending(current))
                         return -ERESTARTSYS;