Subject: Re: linux-next: manual merge of the tty tree with the tty.current tree

From: Greg KH <[email-masked]>
Date: Wed, 4 Oct 2023 08:38:51 +0200

On Wed, Oct 04, 2023 at 01:14:32PM +1100, Stephen Rothwell wrote:
> Hi all,
> 
> On Wed, 4 Oct 2023 12:55:31 +1100 Stephen Rothwell <[email-masked]> wrote:
> >
> > Today's linux-next merge of the tty tree got a conflict in:
> > 
> >   drivers/tty/serial/serial_core.c
> > 
> > between commit:
> > 
> >   8679328eb859 ("serial: Reduce spinlocked portion of uart_rs485_config()")
> > 
> > from the tty.current tree and commit:
> > 
> >   559c7ff4e324 ("serial: core: Use port lock wrappers")
> > 
> > from the tty tree.
> > 
> > I fixed it up (see below) and can carry the fix as necessary. This
> > is now fixed as far as linux-next is concerned, but any non trivial
> > conflicts should be mentioned to your upstream maintainer when your tree
> > is submitted for merging.  You may also want to consider cooperating
> > with the maintainer of the conflicting tree to minimise any particularly
> > complex conflicts.
> 
> Not quite right :-(  This is what I used:
> 
> diff --cc drivers/tty/serial/serial_core.c
> index ca26a8aef2cb,b32bbd7aa3d3..ae1d6782ea0e
> --- a/drivers/tty/serial/serial_core.c
> +++ b/drivers/tty/serial/serial_core.c
> @@@ -1413,9 -1409,7 +1413,9 @@@ static int uart_rs485_config(struct uar
>   	uart_sanitize_serial_rs485(port, rs485);
>   	uart_set_rs485_termination(port, rs485);
>   
> - 	spin_lock_irqsave(&port->lock, flags);
> ++	uart_port_lock_irqsave(port, &flags);
>   	ret = port->rs485_config(port, NULL, rs485);
> - 	spin_unlock_irqrestore(&port->lock, flags);
> ++	uart_port_unlock_irqrestore(port, flags);
>   	if (ret)
>   		memset(rs485, 0, sizeof(*rs485));
>   
> @@@ -2480,12 -2474,13 +2480,12 @@@ int uart_resume_port(struct uart_drive
>   			if (ret == 0) {
>   				if (tty)
>   					uart_change_line_settings(tty, state, NULL);
>  +				uart_rs485_config(uport);
> - 				spin_lock_irq(&uport->lock);
> + 				uart_port_lock_irq(uport);
>   				if (!(uport->rs485.flags & SER_RS485_ENABLED))
>   					ops->set_mctrl(uport, uport->mctrl);
>  -				else
>  -					uart_rs485_config(uport);
>   				ops->start_tx(uport);
> - 				spin_unlock_irq(&uport->lock);
> + 				uart_port_unlock_irq(uport);
>   				tty_port_set_initialized(port, true);
>   			} else {
>   				/*
> @@@ -2592,10 -2587,10 +2592,10 @@@ uart_configure_port(struct uart_driver 
>   		port->mctrl &= TIOCM_DTR;
>   		if (!(port->rs485.flags & SER_RS485_ENABLED))
>   			port->ops->set_mctrl(port, port->mctrl);
> - 		spin_unlock_irqrestore(&port->lock, flags);
>  -		else
>  -			uart_rs485_config(port);
> + 		uart_port_unlock_irqrestore(port, flags);
>   
>  +		uart_rs485_config(port);
>  +
>   		/*
>   		 * If this driver supports console, and it hasn't been
>   		 * successfully registered yet, try to re-register it.
> 
> 
> -- 
> Cheers,
> Stephen Rothwell

Thanks, looks good, I'll use this when I resolve the merge conflict when
it hits my branches.

greg k-h