[media] s5p-fimc: Prevent race conditions during subdevs registration

Make sure when fimc and fimc-lite capture video node is registered
it has valid pipeline_ops assigned to it. Otherwise when a video
node is opened right after is was registered there, might be an
attempt to use ops that are just being assigned, after function
v4l2_device_register_subdev() returns.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/platform/s5p-fimc/fimc-capture.c

@@ -1774,9 +1774,13 @@ static int fimc_capture_subdev_registered(struct v4l2_subdev *sd)
 	if (ret)
 		return ret;
 
+	fimc->pipeline_ops = v4l2_get_subdev_hostdata(sd);
+
 	ret = fimc_register_capture_device(fimc, sd->v4l2_dev);
-	if (ret)
+	if (ret) {
 		fimc_unregister_m2m_device(fimc);
+		fimc->pipeline_ops = NULL;
+	}
 
 	return ret;
 }
@@ -1793,6 +1797,7 @@ static void fimc_capture_subdev_unregistered(struct v4l2_subdev *sd)
 	if (video_is_registered(&fimc->vid_cap.vfd)) {
 		video_unregister_device(&fimc->vid_cap.vfd);
 		media_entity_cleanup(&fimc->vid_cap.vfd.entity);
+		fimc->pipeline_ops = NULL;
 	}
 	kfree(fimc->vid_cap.ctx);
 	fimc->vid_cap.ctx = NULL;

drivers/media/platform/s5p-fimc/fimc-lite.c

@@ -1263,10 +1263,12 @@ static int fimc_lite_subdev_registered(struct v4l2_subdev *sd)
 		return ret;
 
 	video_set_drvdata(vfd, fimc);
+	fimc->pipeline_ops = v4l2_get_subdev_hostdata(sd);
 
 	ret = video_register_device(vfd, VFL_TYPE_GRABBER, -1);
 	if (ret < 0) {
 		media_entity_cleanup(&vfd->entity);
+		fimc->pipeline_ops = NULL;
 		return ret;
 	}
 
@@ -1285,6 +1287,7 @@ static void fimc_lite_subdev_unregistered(struct v4l2_subdev *sd)
 	if (video_is_registered(&fimc->vfd)) {
 		video_unregister_device(&fimc->vfd);
 		media_entity_cleanup(&fimc->vfd.entity);
+		fimc->pipeline_ops = NULL;
 	}
 }
 

drivers/media/platform/s5p-fimc/fimc-mdevice.c

@@ -352,6 +352,7 @@ static int fimc_register_callback(struct device *dev, void *p)
 
 	sd = &fimc->vid_cap.subdev;
 	sd->grp_id = FIMC_GROUP_ID;
+	v4l2_set_subdev_hostdata(sd, (void *)&fimc_pipeline_ops);
 
 	ret = v4l2_device_register_subdev(&fmd->v4l2_dev, sd);
 	if (ret) {
@@ -360,7 +361,6 @@ static int fimc_register_callback(struct device *dev, void *p)
 		return ret;
 	}
 
-	fimc->pipeline_ops = &fimc_pipeline_ops;
 	fmd->fimc[fimc->id] = fimc;
 	return 0;
 }
@@ -375,6 +375,7 @@ static int fimc_lite_register_callback(struct device *dev, void *p)
 		return 0;
 
 	fimc->subdev.grp_id = FLITE_GROUP_ID;
+	v4l2_set_subdev_hostdata(&fimc->subdev, (void *)&fimc_pipeline_ops);
 
 	ret = v4l2_device_register_subdev(&fmd->v4l2_dev, &fimc->subdev);
 	if (ret) {
@@ -384,7 +385,6 @@ static int fimc_lite_register_callback(struct device *dev, void *p)
 		return ret;
 	}
 
-	fimc->pipeline_ops = &fimc_pipeline_ops;
 	fmd->fimc_lite[fimc->index] = fimc;
 	return 0;
 }