usb: gadget: uvc: fix possible lockup in uvc gadget

If the pending buffers in the queue could not be pushed to the udc
endpoint we have to cancel the uvc_queue. Otherwise the gadget will get
stuck on this error. This patch calls uvc_queue_cancel if usb_ep_queue
failed.

Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/function/uvc_video.c

@@ -195,6 +195,7 @@ uvc_video_complete(struct usb_ep *ep, struct usb_request *req)
 		printk(KERN_INFO "Failed to queue request (%d).\n", ret);
 		usb_ep_set_halt(ep);
 		spin_unlock_irqrestore(&video->queue.irqlock, flags);
+		uvc_queue_cancel(queue, 0);
 		goto requeue;
 	}
 	spin_unlock_irqrestore(&video->queue.irqlock, flags);
@@ -281,6 +282,7 @@ error:
 static int
 uvc_video_pump(struct uvc_video *video)
 {
+	struct uvc_video_queue *queue = &video->queue;
 	struct usb_request *req;
 	struct uvc_buffer *buf;
 	unsigned long flags;
@@ -322,6 +324,7 @@ uvc_video_pump(struct uvc_video *video)
 			printk(KERN_INFO "Failed to queue request (%d)\n", ret);
 			usb_ep_set_halt(video->ep);
 			spin_unlock_irqrestore(&video->queue.irqlock, flags);
+			uvc_queue_cancel(queue, 0);
 			break;
 		}
 		spin_unlock_irqrestore(&video->queue.irqlock, flags);