USB: ch341: clean up line-status handling

Clean up line-status handling.

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

1 files changed, 14 insertions, 8 deletions

diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index f647dbdcb27d..9dd94a7e08b9 100644
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -444,24 +444,30 @@ static void ch341_update_line_status(struct usb_serial_port *port,
                                         unsigned char *data, size_t len)
 {
         struct ch341_private *priv = usb_get_serial_port_data(port);
+        struct tty_struct *tty;
         unsigned long flags;
-        u8 prev_line_status = priv->line_status;
+        u8 status;
+        u8 delta;
 
         if (len < 4)
                 return;
 
+        status = ~data[2] & CH341_BITS_MODEM_STAT;
+
         spin_lock_irqsave(&priv->lock, flags);
-        priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
-        if ((data[1] & CH341_MULT_STAT))
+        delta = status ^ priv->line_status;
+        priv->line_status = status;
+        if (data[1] & CH341_MULT_STAT)
                 priv->multi_status_change = 1;
         spin_unlock_irqrestore(&priv->lock, flags);
 
-        if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD) {
-                struct tty_struct *tty = tty_port_tty_get(&port->port);
-                if (tty)
+        if (delta & CH341_BIT_DCD) {
+                tty = tty_port_tty_get(&port->port);
+                if (tty) {
                         usb_serial_handle_dcd_change(port, tty,
-                                        priv->line_status & CH341_BIT_DCD);
-                tty_kref_put(tty);
+                                                status & CH341_BIT_DCD);
+                        tty_kref_put(tty);
+                }
         }
 
         wake_up_interruptible(&port->port.delta_msr_wait);