USB: serial: clean up chars_in_buffer

No need to grab disconnect mutex in chars_in_buffer now that no
sub-driver is or should be querying hardware buffers anymore. (They
should use wait_until_sent.)

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

1 files changed, 2 insertions, 9 deletions

diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 60caf9cb99f4..4753c005cfb6 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -359,20 +359,13 @@ static int serial_chars_in_buffer(struct tty_struct *tty)
 {
         struct usb_serial_port *port = tty->driver_data;
         struct usb_serial *serial = port->serial;
-        int count = 0;
 
         dev_dbg(tty->dev, "%s\n", __func__);
 
-        mutex_lock(&serial->disc_mutex);
-        /* if the device was unplugged then any remaining characters
-           fell out of the connector ;) */
         if (serial->disconnected)
-                count = 0;
-        else
-                count = serial->type->chars_in_buffer(tty);
-        mutex_unlock(&serial->disc_mutex);
+                return 0;
 
-        return count;
+        return serial->type->chars_in_buffer(tty);
 }
 
 static void serial_wait_until_sent(struct tty_struct *tty, int timeout)