Re: [PATCH 1/1] USB-SERIAL : Changing usb_serial_generic_open prototype

[Johan Hovold <johan@kernel.org>]

On Sat, May 30, 2015 at 06:47:20PM +0530, Abhishek Bist wrote:
> While designing a usb to uart converter driver open function I am using
> usb_serial_generic_open, but wouldn't find need to pass tty as an argument.
> As it is not performing any task for further significance.
> 	So, This patch proposed a change in usb_serial_generic_open 
> function prototype which has struct tty_struct as a first argument.
> 
> usb_serial_generic_open(struct tty_struct *tty, 
> 	struct usb_serial_port *port);
> 
> Signed-off-by: Abhishek Bist <ishubist@gmail.com>
 
> diff --git a/include/linux/usb/serial.h b/include/linux/usb/serial.h
> index 704a1ab..c8ed44a 100644
> --- a/include/linux/usb/serial.h
> +++ b/include/linux/usb/serial.h
> @@ -318,8 +318,7 @@ static inline void usb_serial_console_disconnect(struct usb_serial *serial) {}
>  /* Functions needed by other parts of the usbserial core */
>  extern struct usb_serial_port *usb_serial_port_get_by_minor(unsigned int minor);
>  extern void usb_serial_put(struct usb_serial *serial);
> -extern int usb_serial_generic_open(struct tty_struct *tty,
> -	struct usb_serial_port *port);
> +extern int usb_serial_generic_open(struct usb_serial_port *port);
>  extern int usb_serial_generic_write_start(struct usb_serial_port *port,
>  							gfp_t mem_flags);
>  extern int usb_serial_generic_write(struct tty_struct *tty,

This does not work as usb_serial_generic_open is the default driver
callback.

If you had compile tested your patch you would have seen the following
warning:

linux/drivers/usb/serial/usb-serial.c: In function 'usb_serial_operations_init':
linux/drivers/usb/serial/usb-serial.c:1318:19: warning: assignment from incompatible pointer type
    type->function = usb_serial_generic_##function; \
                   ^
linux/drivers/usb/serial/usb-serial.c:1326:2: note: in expansion of macro 'set_to_generic_if_null'
  set_to_generic_if_null(device, open);
  ^

Johan