[media] v4l: subdev: tolerate null in media_entity_to_v4l2_subdev

Return NULL, if a null entity is parsed for it's v4l2_subdev

Currently, the callers of media_entity_to_v4l2_subdev() need to
make sure that the subdev is non-NULL, for example, when it is
obtained from media_entity_remote_pad().

As this is a recurring pattern, add the check at the macro in order
to avoid additional checks at the callers.

Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index a407601..0f92ebd 100644 (file)
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -826,8 +826,15 @@ struct v4l2_subdev {
        struct v4l2_subdev_platform_data *pdata;
 };
 
-#define media_entity_to_v4l2_subdev(ent) \
-       container_of(ent, struct v4l2_subdev, entity)
+#define media_entity_to_v4l2_subdev(ent)                               \
+({                                                                     \
+       typeof(ent) __me_sd_ent = (ent);                                \
+                                                                       \
+       __me_sd_ent ?                                                   \
+               container_of(__me_sd_ent, struct v4l2_subdev, entity) : \
+               NULL;                                                   \
+})
+
 #define vdev_to_v4l2_subdev(vdev) \
        ((struct v4l2_subdev *)video_get_drvdata(vdev))