Re: [RFC] usb: dwc: ep0: Use -ESHUTDOWN in dwc3_ep0_stall_restart

[Thinh Nguyen <Thinh.Nguyen@synopsys.com>]

On Wed, Nov 22, 2023, Uttkarsh Aggarwal wrote:
> Current implementation blocks the running operations when Plug-out and
> Plug-In is performed continuously, process gets stuck in
> dwc3_thread_interrupt().
> 
> Code Flow:
> 
> 	CPU1
> 
> 	->Gadget_start
> 	->dwc3_interrupt
> 	->dwc3_thread_interrupt
> 	->dwc3_process_event_buf
> 	->dwc3_process_event_entry
> 	->dwc3_endpoint_interrupt
> 	->dwc3_ep0_interrupt
> 	->dwc3_ep0_inspect_setup
> 	->dwc3_ep0_stall_and_restart
> 
> By this time if pending_list is not empty, it will get the next request
> on the given list and calls dwc3_gadget_giveback which will unmap request
> and call its complete() callback to notify upper layers that it has
> completed. Currently  dwc3_gadget_giveback status is set to-ECONNRESET,
> whereas it should be -ESHUTDOWN.
> 
> Cc: <stable@vger.kernel.org>
> Fixes: d742220b3577 ("usb: dwc3: ep0: giveback requests on stall_and_restart")
> Signed-off-by: Uttkarsh Aggarwal <quic_uaggarwa@quicinc.com>
> ---
>  drivers/usb/dwc3/ep0.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
> index b94243237293..8317fedda1c0 100644
> --- a/drivers/usb/dwc3/ep0.c
> +++ b/drivers/usb/dwc3/ep0.c
> @@ -238,7 +238,7 @@ void dwc3_ep0_stall_and_restart(struct dwc3 *dwc)
>  		struct dwc3_request	*req;
>  
>  		req = next_request(&dep->pending_list);
> -		dwc3_gadget_giveback(dep, req, -ECONNRESET);
> +		dwc3_gadget_giveback(dep, req, -ESHUTDOWN);

There are other conditions which should return -ECONNRESET (e.g. invalid
length, direction, got cancelled). For the particular condition that you
want for -ESHUTDOWN, I think you can use the dwc->connected field to
check for that.

BR,
Thinh

>  	}
>  
>  	dwc->eps[0]->trb_enqueue = 0;
> -- 
> 2.17.1
>