Re: [PATCH 01/36] serial: Add uart_rs485_config()

[Lukas Wunner]

On Mon, Jun 06, 2022 at 01:03:58PM +0300, Ilpo Järvinen wrote:
> A few serial drivers make a call to rs485_config() themselves (all
> these seem to relate to init). Convert them all to use a common helper
> which makes it easy to make adjustments on tasks related to it as
> serial_rs485 struct sanitization is going to be added.
[...]
 --- a/drivers/tty/serial/serial_core.c
> +++ b/drivers/tty/serial/serial_core.c
> @@ -1276,6 +1276,12 @@ static int uart_get_icount(struct tty_struct *tty,
>  	return 0;
>  }
>  
> +int uart_rs485_config(struct uart_port *port)
> +{
> +	return port->rs485_config(port, &port->rs485);
> +}
> +EXPORT_SYMBOL_GPL(uart_rs485_config);

Why doesn't this helper acquire the port spinlock, unlike
uart_set_rs485_config()?  Is this safe?  Do all callers hold the lock?
Do we need an assertion to verify the lock is held?

Thanks,

Lukas