usb: gadget: uvc: stop pump thread on video disable

Since the uvc-video gadget driver is using the v4l2 interface,
the streamon and streamoff can be triggered at any times. To ensure
that the pump worker will be closed as soon the userspace is
calling streamoff we synchronize the state of the gadget ensuring
the pump worker to bail out.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Link: https://lore.kernel.org/r/20230911140530.2995138-2-m.grzeschik@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/function/uvc_video.c

@@ -384,13 +384,14 @@ static void uvcg_video_pump(struct work_struct *work)
 	struct uvc_video_queue *queue = &video->queue;
 	/* video->max_payload_size is only set when using bulk transfer */
 	bool is_bulk = video->max_payload_size;
+	struct uvc_device *uvc = video->uvc;
 	struct usb_request *req = NULL;
 	struct uvc_buffer *buf;
 	unsigned long flags;
 	bool buf_done;
 	int ret;
 
-	while (video->ep->enabled) {
+	while (video->ep->enabled && uvc->state == UVC_STATE_STREAMING) {
 		/*
 		 * Retrieve the first available USB request, protected by the
 		 * request lock.
@@ -488,6 +489,7 @@ static void uvcg_video_pump(struct work_struct *work)
  */
 int uvcg_video_enable(struct uvc_video *video, int enable)
 {
+	struct uvc_device *uvc = video->uvc;
 	unsigned int i;
 	int ret;
 
@@ -498,6 +500,8 @@ int uvcg_video_enable(struct uvc_video *video, int enable)
 	}
 
 	if (!enable) {
+		uvc->state = UVC_STATE_CONNECTED;
+
 		cancel_work_sync(&video->pump);
 		uvcg_queue_cancel(&video->queue, 0);
 
@@ -523,6 +527,8 @@ int uvcg_video_enable(struct uvc_video *video, int enable)
 		video->encode = video->queue.use_sg ?
 			uvc_video_encode_isoc_sg : uvc_video_encode_isoc;
 
+	uvc->state = UVC_STATE_STREAMING;
+
 	video->req_int_count = 0;
 
 	queue_work(video->async_wq, &video->pump);