staging: dwc2: fix dwc2_hcd_qtd_add()

The logic in dwc2_hcd_qtd_add() was a bit messy, and one of the
error exit paths was broken. Fix it up.
Signed-off-by: Paul Zimmerman <paulz@synopsys.com>
Tested-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/dwc2/hcd_queue.c

@@ -197,6 +197,9 @@ static struct dwc2_qh *dwc2_hcd_qh_create(struct dwc2_hsotg *hsotg,
 {
 	struct dwc2_qh *qh;
 
+	if (!urb->priv)
+		return NULL;
+
 	/* Allocate memory */
 	qh = kzalloc(sizeof(*qh), mem_flags);
 	if (!qh)
@@ -638,7 +641,7 @@ int dwc2_hcd_qtd_add(struct dwc2_hsotg *hsotg, struct dwc2_qtd *qtd,
 	struct dwc2_hcd_urb *urb = qtd->urb;
 	unsigned long flags;
 	int allocated = 0;
-	int retval = 0;
+	int retval;
 
 	/*
 	 * Get the QH which holds the QTD-list to insert to. Create QH if it
@@ -652,8 +655,19 @@ int dwc2_hcd_qtd_add(struct dwc2_hsotg *hsotg, struct dwc2_qtd *qtd,
 	}
 
 	spin_lock_irqsave(&hsotg->lock, flags);
+
 	retval = dwc2_hcd_qh_add(hsotg, *qh);
-	if (retval && allocated) {
+	if (retval)
+		goto fail;
+
+	qtd->qh = *qh;
+	list_add_tail(&qtd->qtd_list_entry, &(*qh)->qtd_list);
+	spin_unlock_irqrestore(&hsotg->lock, flags);
+
+	return 0;
+
+fail:
+	if (allocated) {
 		struct dwc2_qtd *qtd2, *qtd2_tmp;
 		struct dwc2_qh *qh_tmp = *qh;
 
@@ -668,8 +682,6 @@ int dwc2_hcd_qtd_add(struct dwc2_hsotg *hsotg, struct dwc2_qtd *qtd,
 		spin_unlock_irqrestore(&hsotg->lock, flags);
 		dwc2_hcd_qh_free(hsotg, qh_tmp);
 	} else {
-		qtd->qh = *qh;
-		list_add_tail(&qtd->qtd_list_entry, &(*qh)->qtd_list);
 		spin_unlock_irqrestore(&hsotg->lock, flags);
 	}