linux-kernel - Re: [net-next v4 3/8] net: wwan: core: split port unregister and stop

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Message-ID: <CAFEp6-3Ctq5h2r-grJ4UGW-EZnkaM0s_AtsAQjH=pe8XabRH1A@mail.gmail.com>
Date: Tue, 6 Jan 2026 21:34:40 +0100
From: Loic Poulain <loic.poulain@....qualcomm.com>
To: Slark Xiao <slark_xiao@....com>
Cc: ryazanov.s.a@...il.com, johannes@...solutions.net, andrew+netdev@...n.ch,
        davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
        pabeni@...hat.com, mani@...nel.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [net-next v4 3/8] net: wwan: core: split port unregister and stop

On Mon, Jan 5, 2026 at 11:21 AM Slark Xiao <slark_xiao@....com> wrote:
>
> From: Sergey Ryazanov <ryazanov.s.a@...il.com>
>
> Upcoming GNSS (NMEA) port type support requires exporting it via the
> GNSS subsystem. On another hand, we still need to do basic WWAN core
> work: call the port stop operation, purge queues, release the parent
> WWAN device, etc. To reuse as much code as possible, split the port
> unregistering function into the deregistration of a regular WWAN port
> device, and the common port tearing down code.
>
> In order to keep more code generic, break the device_unregister() call
> into device_del() and put_device(), which release the port memory
> uniformly.
>
> Signed-off-by: Sergey Ryazanov <ryazanov.s.a@...il.com>

Reviewed-by: Loic Poulain <loic.poulain@....qualcomm.com>


> ---
>  drivers/net/wwan/wwan_core.c | 23 ++++++++++++++++++-----
>  1 file changed, 18 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/net/wwan/wwan_core.c b/drivers/net/wwan/wwan_core.c
> index edee5ff48f28..c735b9830e6e 100644
> --- a/drivers/net/wwan/wwan_core.c
> +++ b/drivers/net/wwan/wwan_core.c
> @@ -476,6 +476,18 @@ static int wwan_port_register_wwan(struct wwan_port *port)
>         return 0;
>  }
>
> +/* Unregister a regular WWAN port (e.g. AT, MBIM, etc) */
> +static void wwan_port_unregister_wwan(struct wwan_port *port)
> +{
> +       struct wwan_device *wwandev = to_wwan_dev(port->dev.parent);
> +
> +       dev_set_drvdata(&port->dev, NULL);
> +
> +       dev_info(&wwandev->dev, "port %s disconnected\n", dev_name(&port->dev));
> +
> +       device_del(&port->dev);
> +}
> +
>  struct wwan_port *wwan_create_port(struct device *parent,
>                                    enum wwan_port_type type,
>                                    const struct wwan_port_ops *ops,
> @@ -536,18 +548,19 @@ void wwan_remove_port(struct wwan_port *port)
>         struct wwan_device *wwandev = to_wwan_dev(port->dev.parent);
>
>         mutex_lock(&port->ops_lock);
> -       if (port->start_count)
> +       if (port->start_count) {
>                 port->ops->stop(port);
> +               port->start_count = 0;
> +       }
>         port->ops = NULL; /* Prevent any new port operations (e.g. from fops) */
>         mutex_unlock(&port->ops_lock);
>
>         wake_up_interruptible(&port->waitqueue);
> -
>         skb_queue_purge(&port->rxq);
> -       dev_set_drvdata(&port->dev, NULL);
>
> -       dev_info(&wwandev->dev, "port %s disconnected\n", dev_name(&port->dev));
> -       device_unregister(&port->dev);
> +       wwan_port_unregister_wwan(port);
> +
> +       put_device(&port->dev);
>
>         /* Release related wwan device */
>         wwan_remove_dev(wwandev);
> --
> 2.25.1
>