USB: ch341: refactor line-status handling

Refactor line-status handling.

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

1 files changed, 28 insertions, 23 deletions

diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index 8908760cca9f..f647dbdcb27d 100644
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -440,6 +440,33 @@ static int ch341_tiocmset(struct tty_struct *tty,
         return ch341_set_handshake(port->serial->dev, control);
 }
 
+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);
+        unsigned long flags;
+        u8 prev_line_status = priv->line_status;
+
+        if (len < 4)
+                return;
+
+        spin_lock_irqsave(&priv->lock, flags);
+        priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
+        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)
+                        usb_serial_handle_dcd_change(port, tty,
+                                        priv->line_status & CH341_BIT_DCD);
+                tty_kref_put(tty);
+        }
+
+        wake_up_interruptible(&port->port.delta_msr_wait);
+}
+
 static void ch341_read_int_callback(struct urb *urb)
 {
         struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
@@ -466,29 +493,7 @@ static void ch341_read_int_callback(struct urb *urb)
 
         usb_serial_debug_data(&port->dev, __func__,
                               urb->actual_length, urb->transfer_buffer);
-
-        if (actual_length >= 4) {
-                struct ch341_private *priv = usb_get_serial_port_data(port);
-                unsigned long flags;
-                u8 prev_line_status = priv->line_status;
-
-                spin_lock_irqsave(&priv->lock, flags);
-                priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
-                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)
-                                usb_serial_handle_dcd_change(port, tty,
-                                            priv->line_status & CH341_BIT_DCD);
-                        tty_kref_put(tty);
-                }
-
-                wake_up_interruptible(&port->port.delta_msr_wait);
-        }
-
+        ch341_update_line_status(port, data, actual_length);
 exit:
         status = usb_submit_urb(urb, GFP_ATOMIC);
         if (status)