Re: [PATCH] tty/serial_core: Introduce lock mechanism for RS485

[One Thousand Gnomes]

> @@ -1154,8 +1154,16 @@ static int uart_get_icount(struct tty_struct *tty,
>  static int uart_get_rs485_config(struct uart_port *port,
>  			 struct serial_rs485 __user *rs485)
>  {
> -	if (copy_to_user(rs485, &port->rs485, sizeof(port->rs485)))
> +	unsigned long flags;
> +	int ret;
> +
> +	spin_lock_irqsave(&port->lock, flags);
> +	ret = copy_to_user(rs485, &port->rs485, sizeof(port->rs485));
> +	spin_unlock_irqrestore(&port->lock, flags);

Looks good apart from this bit.. The copy needs to go to a temporary
before the lock is taken otherwise we may sleep on a pagefault with irqs
off

Alan
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