V4L/DVB (7689): pvrusb2-dvb: Rework module tear-down

Rather than making an explicit call to tear down the pvrusb2-dvb
module, use the callback in the pvr2_channel structure.  This has the
advantage that now tear-down only happens when it makes sense.  The
previous implementation had scenarios where it was possible for the
tear-down call to happen without a prior initialization.
Signed-off-by: Mike Isely <isely@pobox.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

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

@@ -386,30 +386,37 @@ static int pvr2_dvb_frontend_exit(struct pvr2_dvb_adapter *adap)
 	return 0;
 }
 
+static void pvr2_dvb_done(struct pvr2_dvb_adapter *adap)
+{
+	pvr2_dvb_stream_end(adap);
+	pvr2_dvb_frontend_exit(adap);
+	pvr2_dvb_adapter_exit(adap);
+	pvr2_channel_done(&adap->channel);
+}
+
+static void pvr2_dvb_internal_check(struct pvr2_channel *chp)
+{
+	struct pvr2_dvb_adapter *adap;
+	adap = container_of(chp, struct pvr2_dvb_adapter, channel);
+	if (!adap->channel.mc_head->disconnect_flag) return;
+	pvr2_dvb_done(adap);
+}
+
 int pvr2_dvb_init(struct pvr2_context *pvr)
 {
 	int ret = 0;
 	struct pvr2_dvb_adapter *adap;
 	adap = &pvr->hdw->dvb;
-	adap->init = !0;
 	pvr2_channel_init(&adap->channel, pvr);
+	adap->channel.check_func = pvr2_dvb_internal_check;
 	init_waitqueue_head(&adap->buffer_wait_data);
 	mutex_init(&pvr->hdw->dvb.lock);
 	ret = pvr2_dvb_adapter_init(&pvr->hdw->dvb);
 	if (ret < 0) goto fail;
 	ret = pvr2_dvb_frontend_init(&pvr->hdw->dvb);
+	return ret;
 fail:
+	pvr2_channel_done(&adap->channel);
 	return ret;
 }
 
-int pvr2_dvb_exit(struct pvr2_context *pvr)
-{
-	struct pvr2_dvb_adapter *adap;
-	adap = &pvr->hdw->dvb;
-	if (!adap->init) return 0;
-	pvr2_dvb_stream_end(adap);
-	pvr2_dvb_frontend_exit(adap);
-	pvr2_dvb_adapter_exit(adap);
-	pvr2_channel_done(&adap->channel);
-	return 0;
-}

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

@@ -27,7 +27,6 @@ struct pvr2_dvb_adapter {
 
 	unsigned int		digital_up:1;
 	unsigned int		stream_run:1;
-	unsigned int		init:1;
 
 	wait_queue_head_t	buffer_wait_data;
 	char			*buffer_storage[PVR2_DVB_BUFFER_COUNT];
@@ -39,6 +38,5 @@ struct pvr2_dvb_props {
 };
 
 int pvr2_dvb_init(struct pvr2_context *pvr);
-int pvr2_dvb_exit(struct pvr2_context *pvr);
 
 #endif /* __PVRUSB2_DVB_H__ */

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

@@ -99,9 +99,6 @@ static void pvr_disconnect(struct usb_interface *intf)
 
 	pvr2_trace(PVR2_TRACE_INIT,"pvr_disconnect(pvr=%p) BEGIN",pvr);
 
-#ifdef CONFIG_VIDEO_PVRUSB2_DVB
-	pvr2_dvb_exit(pvr);
-#endif
 	usb_set_intfdata (intf, NULL);
 	pvr2_context_disconnect(pvr);