Re: [PATCH v11 2/4] usb: add apis for offload usage tracking

[Greg KH <gregkh@linuxfoundation.org>]

On Tue, Apr 08, 2025 at 03:57:22AM +0000, Guan-Yu Lin wrote:
> --- a/include/linux/usb.h
> +++ b/include/linux/usb.h
> @@ -647,6 +647,7 @@ struct usb3_lpm_parameters {
>   *	parent->hub_delay + wHubDelay + tTPTransmissionDelay (40ns)
>   *	Will be used as wValue for SetIsochDelay requests.
>   * @use_generic_driver: ask driver core to reprobe using the generic driver.
> + * @offload_usage: number of offload activities happening on this usb device.
>   *
>   * Notes:
>   * Usbcore drivers should not set usbdev->state directly.  Instead use
> @@ -733,6 +734,8 @@ struct usb_device {
>  
>  	u16 hub_delay;
>  	unsigned use_generic_driver:1;
> +
> +	refcount_t offload_usage;

You now have 2 different "refcounts" for the same structure, which of
course is crazy and will do nothing but cause massive problems.

I know this isn't going to be used to "reference count" the structure,
and surely you don't need/want the atomic properties of a "real"
reference count, so why isn't this a simple integer?

thanks,

greg k-h