usb: dwc3: gadget: Avoid continuing preparing TRBs during teardown

Add checks similar to dwc3_gadget_ep_queue() before kicking off
transfers after getting an endpoint completion event.   Since cleaning
up completed requests will momentarily unlock dwc->lock, there is a
chance for a sequence like pullup disable to be executed.  This can
lead to preparing a TRB, which will be removed by the pullup disable
routine.
Signed-off-by: Wesley Cheng <wcheng@codeaurora.org>
Link: https://lore.kernel.org/r/1616146285-19149-2-git-send-email-wcheng@codeaurora.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/dwc3/gadget.c

@@ -2917,6 +2917,11 @@ static void dwc3_gadget_ep_cleanup_completed_requests(struct dwc3_ep *dep,
 static bool dwc3_gadget_ep_should_continue(struct dwc3_ep *dep)
 {
 	struct dwc3_request	*req;
+	struct dwc3		*dwc = dep->dwc;
+
+	if (!dep->endpoint.desc || !dwc->pullups_connected ||
+	    !dwc->connected)
+		return false;
 
 	if (!list_empty(&dep->pending_list))
 		return true;