usb: dwc3: gadget: Give back staled requests

If a request is dequeued, the transfer is cancelled. Give back all
the started requests.

In most scenarios, the function driver dequeues all requests of a
transfer when there's a failure. If the function driver follows this,
then it's fine. If not, then we'd be skipping TRBs at different points
within the dequeue and enqueue pointers, making dequeue/enqueue pointers
useless. To enforce and make sure that we're properly skipping TRBs,
cancel all the started requests and give back all the cancelled requests
to the function drivers.

Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index d90a8a5..a99152e 100644 (file)
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1560,6 +1560,11 @@ static int dwc3_gadget_ep_dequeue(struct usb_ep *ep,
 
        spin_lock_irqsave(&dwc->lock, flags);
 
+       list_for_each_entry(r, &dep->cancelled_list, list) {
+               if (r == req)
+                       goto out0;
+       }
+
        list_for_each_entry(r, &dep->pending_list, list) {
                if (r == req)
                        break;
@@ -1571,13 +1576,21 @@ static int dwc3_gadget_ep_dequeue(struct usb_ep *ep,
                                break;
                }
                if (r == req) {
+                       struct dwc3_request *t;
+
                        /* wait until it is processed */
                        dwc3_stop_active_transfer(dep, true, true);
 
                        if (!r->trb)
                                goto out0;
 
-                       dwc3_gadget_move_cancelled_request(req);
+                       /*
+                        * Remove any started request if the transfer is
+                        * cancelled.
+                        */
+                       list_for_each_entry_safe(r, t, &dep->started_list, list)
+                               dwc3_gadget_move_cancelled_request(r);
+
                        if (dep->flags & DWC3_EP_TRANSFER_STARTED)
                                goto out0;
                        else