linux-kernel - Re: [PATCH] serial: core: Revert port

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Date:   Wed, 9 Aug 2023 14:16:57 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Tony Lindgren <tony@...mide.com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jirislaby@...nel.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Andy Shevchenko <andriy.shevchenko@...el.com>,
        Dhruva Gole <d-gole@...com>,
        Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,
        John Ogness <john.ogness@...utronix.de>,
        Johan Hovold <johan@...nel.org>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Vignesh Raghavendra <vigneshr@...com>,
        linux-kernel@...r.kernel.org, linux-serial@...r.kernel.org,
        Guenter Roeck <groeck7@...il.com>
Subject: Re: [PATCH] serial: core: Revert port_id use

On 8/8/23 22:26, Tony Lindgren wrote:
> Hi,
> 
> * Guenter Roeck <linux@...ck-us.net> [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@...il.com>
>>> Signed-off-by: Tony Lindgren <tony@...mide.com>
>>
>> Tested-by: Guenter Roeck <linux@...ck-us.net>
> 
> 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@...ck-us.net>

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);
>   }
>