From: Kieran Bingham <kieran.bingham+renesas@xxxxxxxxxxxxxxxx> Return NULL, if a null entity is parsed for it's v4l2_subdev Signed-off-by: Kieran Bingham <kieran.bingham+renesas@xxxxxxxxxxxxxxxx> --- Not sure if this patch ever made it out of my mailbox: Here's the respin with the parameter evaluated only once. v4: - Improve macro usage to evaluate ent only once include/media/v4l2-subdev.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h index a40760174797..0f92ebd2d710 100644 --- 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)) -- 2.7.4