usb: dwc2: host: allocate qh before atomic enqueue

To avoid sleep while atomic bugs, allocate qh before calling
dwc2_hcd_urb_enqueue. qh pointer can be used directly now instead of
passing ep->hcpriv as double pointer.

Acked-by: John Youn <johnyoun@synopsys.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@intel.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/dwc2/hcd.c

@@ -359,7 +359,7 @@ void dwc2_hcd_stop(struct dwc2_hsotg *hsotg)
 
 /* Caller must hold driver lock */
 static int dwc2_hcd_urb_enqueue(struct dwc2_hsotg *hsotg,
-				struct dwc2_hcd_urb *urb, void **ep_handle,
+				struct dwc2_hcd_urb *urb, struct dwc2_qh *qh,
 				gfp_t mem_flags)
 {
 	struct dwc2_qtd *qtd;
@@ -391,8 +391,7 @@ static int dwc2_hcd_urb_enqueue(struct dwc2_hsotg *hsotg,
 		return -ENOMEM;
 
 	dwc2_hcd_qtd_init(qtd, urb);
-	retval = dwc2_hcd_qtd_add(hsotg, qtd, (struct dwc2_qh **)ep_handle,
-				  mem_flags);
+	retval = dwc2_hcd_qtd_add(hsotg, qtd, qh);
 	if (retval) {
 		dev_err(hsotg->dev,
 			"DWC OTG HCD URB Enqueue failed adding QTD. Error status %d\n",
@@ -2445,6 +2444,8 @@ static int _dwc2_hcd_urb_enqueue(struct usb_hcd *hcd, struct urb *urb,
 	u32 tflags = 0;
 	void *buf;
 	unsigned long flags;
+	struct dwc2_qh *qh;
+	bool qh_allocated = false;
 
 	if (dbg_urb(urb)) {
 		dev_vdbg(hsotg->dev, "DWC OTG HCD URB Enqueue\n");
@@ -2523,13 +2524,24 @@ static int _dwc2_hcd_urb_enqueue(struct usb_hcd *hcd, struct urb *urb,
 						 urb->iso_frame_desc[i].length);
 
 	urb->hcpriv = dwc2_urb;
+	qh = (struct dwc2_qh *) ep->hcpriv;
+	/* Create QH for the endpoint if it doesn't exist */
+	if (!qh) {
+		qh = dwc2_hcd_qh_create(hsotg, dwc2_urb, mem_flags);
+		if (!qh) {
+			retval = -ENOMEM;
+			goto fail0;
+		}
+		ep->hcpriv = qh;
+		qh_allocated = true;
+	}
 
 	spin_lock_irqsave(&hsotg->lock, flags);
 	retval = usb_hcd_link_urb_to_ep(hcd, urb);
 	if (retval)
 		goto fail1;
 
-	retval = dwc2_hcd_urb_enqueue(hsotg, dwc2_urb, &ep->hcpriv, mem_flags);
+	retval = dwc2_hcd_urb_enqueue(hsotg, dwc2_urb, qh, mem_flags);
 	if (retval)
 		goto fail2;
 
@@ -2549,6 +2561,17 @@ fail2:
 fail1:
 	spin_unlock_irqrestore(&hsotg->lock, flags);
 	urb->hcpriv = NULL;
+	if (qh_allocated) {
+		struct dwc2_qtd *qtd2, *qtd2_tmp;
+
+		ep->hcpriv = NULL;
+		dwc2_hcd_qh_unlink(hsotg, qh);
+		/* Free each QTD in the QH's QTD list */
+		list_for_each_entry_safe(qtd2, qtd2_tmp, &qh->qtd_list,
+							 qtd_list_entry)
+			dwc2_hcd_qtd_unlink_and_free(hsotg, qtd2, qh);
+		dwc2_hcd_qh_free(hsotg, qh);
+	}
 fail0:
 	kfree(dwc2_urb);
 

drivers/usb/dwc2/hcd.h

@@ -463,6 +463,9 @@ extern void dwc2_hcd_queue_transactions(struct dwc2_hsotg *hsotg,
 /* Schedule Queue Functions */
 /* Implemented in hcd_queue.c */
 extern void dwc2_hcd_init_usecs(struct dwc2_hsotg *hsotg);
+extern struct dwc2_qh *dwc2_hcd_qh_create(struct dwc2_hsotg *hsotg,
+					  struct dwc2_hcd_urb *urb,
+					  gfp_t mem_flags);
 extern void dwc2_hcd_qh_free(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh);
 extern int dwc2_hcd_qh_add(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh);
 extern void dwc2_hcd_qh_unlink(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh);
@@ -471,7 +474,7 @@ extern void dwc2_hcd_qh_deactivate(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh,
 
 extern void dwc2_hcd_qtd_init(struct dwc2_qtd *qtd, struct dwc2_hcd_urb *urb);
 extern int dwc2_hcd_qtd_add(struct dwc2_hsotg *hsotg, struct dwc2_qtd *qtd,
-			    struct dwc2_qh **qh, gfp_t mem_flags);
+			    struct dwc2_qh *qh);
 
 /* Unlinks and frees a QTD */
 static inline void dwc2_hcd_qtd_unlink_and_free(struct dwc2_hsotg *hsotg,

drivers/usb/dwc2/hcd_queue.c

@@ -191,7 +191,7 @@ static void dwc2_qh_init(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh,
  *
  * Return: Pointer to the newly allocated QH, or NULL on error
  */
-static struct dwc2_qh *dwc2_hcd_qh_create(struct dwc2_hsotg *hsotg,
+struct dwc2_qh *dwc2_hcd_qh_create(struct dwc2_hsotg *hsotg,
 					  struct dwc2_hcd_urb *urb,
 					  gfp_t mem_flags)
 {
@@ -767,57 +767,32 @@ void dwc2_hcd_qtd_init(struct dwc2_qtd *qtd, struct dwc2_hcd_urb *urb)
  *
  * @hsotg:        The DWC HCD structure
  * @qtd:          The QTD to add
- * @qh:           Out parameter to return queue head
- * @atomic_alloc: Flag to do atomic alloc if needed
+ * @qh:           Queue head to add qtd to
  *
  * Return: 0 if successful, negative error code otherwise
  *
- * Finds the correct QH to place the QTD into. If it does not find a QH, it
- * will create a new QH. If the QH to which the QTD is added is not currently
- * scheduled, it is placed into the proper schedule based on its EP type.
+ * If the QH to which the QTD is added is not currently scheduled, it is placed
+ * into the proper schedule based on its EP type.
  */
 int dwc2_hcd_qtd_add(struct dwc2_hsotg *hsotg, struct dwc2_qtd *qtd,
-		     struct dwc2_qh **qh, gfp_t mem_flags)
+		     struct dwc2_qh *qh)
 {
-	struct dwc2_hcd_urb *urb = qtd->urb;
-	int allocated = 0;
 	int retval;
 
-	/*
-	 * Get the QH which holds the QTD-list to insert to. Create QH if it
-	 * doesn't exist.
-	 */
-	if (*qh == NULL) {
-		*qh = dwc2_hcd_qh_create(hsotg, urb, mem_flags);
-		if (*qh == NULL)
-			return -ENOMEM;
-		allocated = 1;
+	if (unlikely(!qh)) {
+		dev_err(hsotg->dev, "%s: Invalid QH\n", __func__);
+		retval = -EINVAL;
+		goto fail;
 	}
 
-	retval = dwc2_hcd_qh_add(hsotg, *qh);
+	retval = dwc2_hcd_qh_add(hsotg, qh);
 	if (retval)
 		goto fail;
 
-	qtd->qh = *qh;
-	list_add_tail(&qtd->qtd_list_entry, &(*qh)->qtd_list);
+	qtd->qh = qh;
+	list_add_tail(&qtd->qtd_list_entry, &qh->qtd_list);
 
 	return 0;
-
 fail:
-	if (allocated) {
-		struct dwc2_qtd *qtd2, *qtd2_tmp;
-		struct dwc2_qh *qh_tmp = *qh;
-
-		*qh = NULL;
-		dwc2_hcd_qh_unlink(hsotg, qh_tmp);
-
-		/* Free each QTD in the QH's QTD list */
-		list_for_each_entry_safe(qtd2, qtd2_tmp, &qh_tmp->qtd_list,
-					 qtd_list_entry)
-			dwc2_hcd_qtd_unlink_and_free(hsotg, qtd2, qh_tmp);
-
-		dwc2_hcd_qh_free(hsotg, qh_tmp);
-	}
-
 	return retval;
 }