USB: pl2303: clean up line-status handling

Clean up line-status handling somewhat.
Get tty-reference only when actually needed.

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

diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c
index 9951dfddc784aec97a218ad7a290fc95dd293ca0..11de1f169308be4ae0eb9c13b5086bf6d06478a3 100644 (file)
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -808,7 +808,8 @@ static void pl2303_update_line_status(struct usb_serial_port *port,
        struct tty_struct *tty;
        unsigned long flags;
        unsigned int status_idx = UART_STATE_INDEX;
-       u8 prev_line_status;
+       u8 status;
+       u8 delta;
 
        if (spriv->quirks & PL2303_QUIRK_UART_STATE_IDX0)
                status_idx = 0;
@@ -816,24 +817,27 @@ static void pl2303_update_line_status(struct usb_serial_port *port,
        if (actual_length < status_idx + 1)
                return;
 
+       status = data[status_idx];
+
        /* Save off the uart status for others to look at */
        spin_lock_irqsave(&priv->lock, flags);
-       prev_line_status = priv->line_status;
-       priv->line_status = data[status_idx];
+       delta = priv->line_status ^ status;
+       priv->line_status = status;
        spin_unlock_irqrestore(&priv->lock, flags);
 
-       if (priv->line_status & UART_BREAK_ERROR)
+       if (status & UART_BREAK_ERROR)
                usb_serial_handle_break(port);
 
        wake_up_interruptible(&port->port.delta_msr_wait);
 
-       tty = tty_port_tty_get(&port->port);
-       if (!tty)
-               return;
-       if ((priv->line_status ^ prev_line_status) & UART_DCD)
-               usb_serial_handle_dcd_change(port, tty,
-                               priv->line_status & UART_DCD);
-       tty_kref_put(tty);
+       if (delta & UART_DCD) {
+               tty = tty_port_tty_get(&port->port);
+               if (tty) {
+                       usb_serial_handle_dcd_change(port, tty,
+                                                       status & UART_DCD);
+                       tty_kref_put(tty);
+               }
+       }
 }
 
 static void pl2303_read_int_callback(struct urb *urb)