Grab disconnect mutex in chars_in_buffer before checking disconnected flag or calling driver specific function.
This allows subdrivers to query any hardware buffer status without having to handle the locking themselves. Signed-off-by: Johan Hovold <[email protected]> --- drivers/usb/serial/usb-serial.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c index 64bda13..0a17f59 100644 --- a/drivers/usb/serial/usb-serial.c +++ b/drivers/usb/serial/usb-serial.c @@ -361,15 +361,21 @@ static int serial_write_room(struct tty_struct *tty) 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 - port %d\n", __func__, port->number); + mutex_lock(&serial->disc_mutex); /* if the device was unplugged then any remaining characters fell out of the connector ;) */ - if (port->serial->disconnected) - return 0; - /* pass on to the driver specific version of this function */ - return port->serial->type->chars_in_buffer(tty); + if (serial->disconnected) + count = 0; + else + count = serial->type->chars_in_buffer(tty); + mutex_unlock(&serial->disc_mutex); + + return count; } static void serial_throttle(struct tty_struct *tty) -- 1.8.1 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
