Re: [PATCH v3] usbip: Don't submit special requests twice

[Greg Kroah-Hartman]

On Fri, Dec 01, 2023 at 12:10:13AM +0100, Simon Holesch wrote:
> Skip submitting URBs, when identical requests were already sent in
> tweak_special_requests(). Instead call the completion handler directly
> to return the result of the URB.
> 
> Even though submitting those requests twice should be harmless, there
> are USB devices that react poorly to some duplicated requests.
> 
> One example is the ChipIdea controller implementation in U-Boot: The
> second SET_CONFIURATION request makes U-Boot disable and re-enable all
> endpoints. Re-enabling an endpoint in the ChipIdea controller, however,
> was broken until U-Boot commit b272c8792502 ("usb: ci: Fix gadget
> reinit").
> 
> Signed-off-by: Simon Holesch <simon@xxxxxxxxxx>
> ---
> 
> Changes in v3:
> - handle errors in tweak_* routines: send URB if tweaking fails
> 
> Changes in v2:
> - explain change in commit message
> 
> Thanks again for the feedback!
> 
>  drivers/usb/usbip/stub_rx.c | 73 +++++++++++++++++++++++--------------
>  1 file changed, 46 insertions(+), 27 deletions(-)
> 
> diff --git a/drivers/usb/usbip/stub_rx.c b/drivers/usb/usbip/stub_rx.c
> index fc01b31bbb87..76a6f46b8676 100644
> --- a/drivers/usb/usbip/stub_rx.c
> +++ b/drivers/usb/usbip/stub_rx.c
> @@ -144,53 +144,62 @@ static int tweak_set_configuration_cmd(struct urb *urb)
>  	if (err && err != -ENODEV)
>  		dev_err(&sdev->udev->dev, "can't set config #%d, error %d\n",
>  			config, err);
> -	return 0;
> +	return err;
>  }
>  
>  static int tweak_reset_device_cmd(struct urb *urb)
>  {
>  	struct stub_priv *priv = (struct stub_priv *) urb->context;
>  	struct stub_device *sdev = priv->sdev;
> +	int err;
>  
>  	dev_info(&urb->dev->dev, "usb_queue_reset_device\n");
>  
> -	if (usb_lock_device_for_reset(sdev->udev, NULL) < 0) {
> +	err = usb_lock_device_for_reset(sdev->udev, NULL)

You didn't actually build this change, so how was it tested?

{sigh}

greg k-h