From: Arnd Bergmann <arnd@arndb.de>

The newly added function is used from a loadable module, so it has
to be exported the same way as the other function in this file:

ERROR: modpost: "serial_8250_warn_need_ioport" [drivers/tty/serial/8250/8250_pci.ko] undefined!

Fixes: 7c7e6c8924e7 ("tty: serial: handle HAS_IOPORT dependencies")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
The build regression is currently part of my asm-generic tree, so I've
applied this fixup on top.

 drivers/tty/serial/8250/8250_pcilib.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/tty/serial/8250/8250_pcilib.c b/drivers/tty/serial/8250/8250_pcilib.c
index ec4d04177802..3bdccf76f71d 100644
--- a/drivers/tty/serial/8250/8250_pcilib.c
+++ b/drivers/tty/serial/8250/8250_pcilib.c
@@ -19,6 +19,7 @@ int serial_8250_warn_need_ioport(struct pci_dev *dev)
 
 	return -ENXIO;
 }
+EXPORT_SYMBOL_NS_GPL(serial_8250_warn_need_ioport, SERIAL_8250_PCI);
 
 int serial8250_pci_setup_port(struct pci_dev *dev, struct uart_8250_port *port,
 		   u8 bar, unsigned int offset, int regshift)
-- 
2.39.5

On Tue, 2024-10-29 at 15:27 +0000, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> The newly added function is used from a loadable module, so it has
> to be exported the same way as the other function in this file:
> 
> ERROR: modpost: "serial_8250_warn_need_ioport" [drivers/tty/serial/8250/8250_pci.ko] undefined!
> 
> Fixes: 7c7e6c8924e7 ("tty: serial: handle HAS_IOPORT dependencies")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> The build regression is currently part of my asm-generic tree, so I've
> applied this fixup on top.
> 
>  drivers/tty/serial/8250/8250_pcilib.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/tty/serial/8250/8250_pcilib.c b/drivers/tty/serial/8250/8250_pcilib.c
> index ec4d04177802..3bdccf76f71d 100644
> --- a/drivers/tty/serial/8250/8250_pcilib.c
> +++ b/drivers/tty/serial/8250/8250_pcilib.c
> @@ -19,6 +19,7 @@ int serial_8250_warn_need_ioport(struct pci_dev *dev)
>  
>  	return -ENXIO;
>  }
> +EXPORT_SYMBOL_NS_GPL(serial_8250_warn_need_ioport, SERIAL_8250_PCI);
>  
>  int serial8250_pci_setup_port(struct pci_dev *dev, struct uart_8250_port *port,
>  		   u8 bar, unsigned int offset, int regshift)

Looks like I forgot to try the last version plus the temporarily
removed !S390 with allmodconfig instead of allyesconfig. 

Thanks for the fix!

Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com>