Re: [PATCH] serial: core: Revert port_id use

[Guenter Roeck <linux@xxxxxxxxxxxx>]

On 8/8/23 22:26, Tony Lindgren wrote:
> Hi,
>
> * Guenter Roeck <linux@xxxxxxxxxxxx> [230806 13:19]:
> > On Sun, Aug 06, 2023 at 09:20:50AM +0300, Tony Lindgren wrote:
> > > Guenter reports boot issues with duplicate sysfs entries for multiport
> > > drivers. Let's go back to using port->line for now to fix the regression.
> > >
> > > With this change, the serial core port device names are not correct for the
> > > hardware specific 8250 single port drivers, but that's a cosmetic issue for
> > > now.
> > >
> > > Fixes: d962de6ae51f ("serial: core: Fix serial core port id to not use port->line")
> > > Reported-by: Guenter Roeck <groeck7@xxxxxxxxx>
> > > Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
> >
> > Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx>
>
> Thanks for testing.
>
> Guenter, care to also test the patch below on top of this fix and
> see if things still behave for you?
>
> I'll send a proper patch assuming things test fine.

Patch below works for me.

Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx>

Guenter

> Regagrds,
>
> Tony
>
> 8< --------------------
> diff --git a/drivers/tty/serial/serial_base.h b/drivers/tty/serial/serial_base.h
> --- a/drivers/tty/serial/serial_base.h
> +++ b/drivers/tty/serial/serial_base.h
> @@ -16,6 +16,7 @@ struct device;
>   
>   struct serial_ctrl_device {
>   	struct device dev;
> +	struct ida ida;
>   };
>   
>   struct serial_port_device {
> diff --git a/drivers/tty/serial/serial_base_bus.c b/drivers/tty/serial/serial_base_bus.c
> --- a/drivers/tty/serial/serial_base_bus.c
> +++ b/drivers/tty/serial/serial_base_bus.c
> @@ -10,6 +10,7 @@
>   
>   #include <linux/container_of.h>
>   #include <linux/device.h>
> +#include <linux/idr.h>
>   #include <linux/module.h>
>   #include <linux/serial_core.h>
>   #include <linux/slab.h>
> @@ -112,6 +113,8 @@ struct serial_ctrl_device *serial_base_ctrl_add(struct uart_port *port,
>   	if (!ctrl_dev)
>   		return ERR_PTR(-ENOMEM);
>   
> +	ida_init(&ctrl_dev->ida);
> +
>   	err = serial_base_device_init(port, &ctrl_dev->dev,
>   				      parent, &serial_ctrl_type,
>   				      serial_base_ctrl_release,
> @@ -142,16 +145,31 @@ struct serial_port_device *serial_base_port_add(struct uart_port *port,
>   						struct serial_ctrl_device *ctrl_dev)
>   {
>   	struct serial_port_device *port_dev;
> +	unsigned int min = 0, max = ~0U;
>   	int err;
>   
>   	port_dev = kzalloc(sizeof(*port_dev), GFP_KERNEL);
>   	if (!port_dev)
>   		return ERR_PTR(-ENOMEM);
>   
> +	/* Device driver specified port_id vs automatic assignment? */
> +	if (port->port_id) {
> +		min = port->port_id;
> +		max = port->port_id;
> +	}
> +
> +	err = ida_alloc_range(&ctrl_dev->ida, min, max, GFP_KERNEL);
> +	if (err < 0) {
> +		kfree(port_dev);
> +		return ERR_PTR(err);
> +	}
> +
> +	port->port_id = err;
> +
>   	err = serial_base_device_init(port, &port_dev->dev,
>   				      &ctrl_dev->dev, &serial_port_type,
>   				      serial_base_port_release,
> -				      port->ctrl_id, port->line);
> +				      port->ctrl_id, port->port_id);
>   	if (err)
>   		goto err_put_device;
>   
> @@ -165,16 +183,24 @@ struct serial_port_device *serial_base_port_add(struct uart_port *port,
>   
>   err_put_device:
>   	put_device(&port_dev->dev);
> +	ida_free(&ctrl_dev->ida, port->port_id);
>   
>   	return ERR_PTR(err);
>   }
>   
>   void serial_base_port_device_remove(struct serial_port_device *port_dev)
>   {
> +	struct serial_ctrl_device *ctrl_dev;
> +	struct device *parent;
> +
>   	if (!port_dev)
>   		return;
>   
> +	parent = port_dev->dev.parent;
> +	ctrl_dev = to_serial_base_ctrl_device(parent);
> +
>   	device_del(&port_dev->dev);
> +	ida_free(&ctrl_dev->ida, port_dev->port->port_id);
>   	put_device(&port_dev->dev);
>   }
>