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

From: Stephen Rothwell <[email-masked]>
Date: Thu, 11 Apr 2024 14:17:11 +1000

Hi all,

On Thu, 11 Apr 2024 13:57:35 +1000 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:
> 
>   9cf7ea2eeb74 ("serial: core: Clearing the circular buffer before NULLifying it")
> 
> from the tty.current tree and commit:
> 
>   1788cf6a91d9 ("tty: serial: switch from circ_buf to kfifo")
> 
> 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.
> 
> -- 
> Cheers,
> Stephen Rothwell
> 
> diff --cc drivers/tty/serial/serial_core.c
> index 2247efe97250,a78ded8c60b5..000000000000
> --- a/drivers/tty/serial/serial_core.c
> +++ b/drivers/tty/serial/serial_core.c
> @@@ -1788,9 -1773,9 +1773,10 @@@ static void uart_tty_port_shutdown(stru
>   	 * Free the transmit buffer.
>   	 */
>   	uart_port_lock_irq(uport);
>  +	uart_circ_clear(&state->xmit);
> - 	buf = state->xmit.buf;
> - 	state->xmit.buf = NULL;
> + 	buf = port->xmit_buf;
> + 	port->xmit_buf = NULL;
> + 	INIT_KFIFO(port->xmit_fifo);
>   	uart_port_unlock_irq(uport);
>   
>   	free_page((unsigned long)buf);

That didn't work :-(

So I have used the below resolution instead.
-- 
Cheers,
Stephen Rothwell

diff --cc drivers/tty/serial/serial_core.c
index 2247efe97250,a78ded8c60b5..000000000000
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@@ -1788,9 -1773,9 +1773,10 @@@ static void uart_tty_port_shutdown(stru
  	 * Free the transmit buffer.
  	 */
  	uart_port_lock_irq(uport);
- 	uart_circ_clear(&state->xmit);
- 	buf = state->xmit.buf;
- 	state->xmit.buf = NULL;
++	kfifo_reset(&state->port.xmit_fifo);
+ 	buf = port->xmit_buf;
+ 	port->xmit_buf = NULL;
+ 	INIT_KFIFO(port->xmit_fifo);
  	uart_port_unlock_irq(uport);
  
  	free_page((unsigned long)buf);