V4L/DVB (7708): pvrusb2-dvb: Fix stuck thread on streaming abort

If the device fails to stream, the feed thread will block forever
waiting for buffers.  But while in this state it was not looking for
an exit condition from the driver DVB interface.  This caused the
thread to jam.  Implement a new stop flag (which will be set
appropriately) to tell the thread to stop.
Signed-off-by: Mike Isely <isely@pobox.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/video/pvrusb2/pvrusb2-dvb.c

@@ -41,6 +41,7 @@ static int pvr2_dvb_feed_func(struct pvr2_dvb_adapter *adap)
 	stream = adap->channel.stream->stream;
 
 	for (;;) {
+		if (adap->feed_thread_stop) break;
 		if (kthread_should_stop()) break;
 
 		/* Not sure about this... */
@@ -70,10 +71,12 @@ static int pvr2_dvb_feed_func(struct pvr2_dvb_adapter *adap)
 		}
 
 
-		/* Wait until more buffers become available. */
+		/* Wait until more buffers become available or we're
+		   told not to wait any longer. */
 		ret = wait_event_interruptible(
 		    adap->buffer_wait_data,
-		    pvr2_stream_get_ready_count(stream) > 0);
+		    (pvr2_stream_get_ready_count(stream) > 0) ||
+		    adap->feed_thread_stop);
 		if (ret < 0) break;
 	}
 
@@ -107,6 +110,8 @@ static void pvr2_dvb_stream_end(struct pvr2_dvb_adapter *adap)
 	struct pvr2_stream *stream;
 
 	if (adap->thread) {
+		adap->feed_thread_stop = !0;
+		pvr2_dvb_notify(adap);
 		kthread_stop(adap->thread);
 		adap->thread = NULL;
 	}
@@ -177,6 +182,7 @@ static int pvr2_dvb_stream_do_start(struct pvr2_dvb_adapter *adap)
 		if (ret < 0) return ret;
 	}
 
+	adap->feed_thread_stop = 0;
 	adap->thread = kthread_run(pvr2_dvb_feed_thread, adap, "pvrusb2-dvb");
 
 	if (IS_ERR(adap->thread)) {

drivers/media/video/pvrusb2/pvrusb2-dvb.h

@@ -28,6 +28,7 @@ struct pvr2_dvb_adapter {
 	unsigned int		stream_run:1;
 
 	wait_queue_head_t	buffer_wait_data;
+	int			feed_thread_stop;
 	char			*buffer_storage[PVR2_DVB_BUFFER_COUNT];
 };