RE: [PATCH rtw-next] wifi: rtw89: usb: Avoid crash with dynamically added device ID

[Ping-Ke Shih <pkshih@realtek.com>]

Bitterblue Smith <rtl8821cerfe2@gmail.com> wrote:
> Adding a device ID via sysfs causes a crash when the device is plugged
> in, because the driver_info pointer is null.

I don't know about this before. Does it looks like?

   echo "1234 5678" | sudo tee /sys/bus/usb/drivers/my_driver/new_id

> 
> Add a wrapper around rtw89_usb_probe() in each driver to check if
> driver_info is null and provide a reasonable default value for it.
> 
> Signed-off-by: Bitterblue Smith <rtl8821cerfe2@gmail.com>

Acked-by: Ping-Ke Shih <pkshih@realtek.com>

I'd give my acked-by in advance. But you still can consider my opinion below.

> ---
> The PCI side has the same problem, but new device IDs are a lot less
> likely there.

Thanks for the info.

[...]

> +static int rtw8851bu_probe(struct usb_interface *intf,
> +                          const struct usb_device_id *id)
> +{
> +       const struct rtw89_driver_info *info;
> +
> +       if (id->driver_info)
> +               info = (const struct rtw89_driver_info *)id->driver_info;
> +       else
> +               info = &rtw89_8851bu_info;
> +
> +       return rtw89_usb_probe(intf, info);
> +}
> +

If you want to simply specific probe(), here might be 

static int rtw8851bu_probe(struct usb_interface *intf,
                           const struct usb_device_id *id)
{
        return rtw89_usb_probe(intf, id, &rtw89_8851bu_info);
}

Then

int rtw89_usb_probe(struct usb_interface *intf,
                    const struct usb_device_id *id,
                    const struct rtw89_driver_info *default_info)
{
        ...

        info = (const struct rtw89_driver_info *)id->driver_info;
        if (!info)
                info = default_info;
}