Re: [PATCH 3/3] drm/dp_mst: Add __must_check to drm_dp_mst_topology_mgr_resume()

From: Daniel Vetter
Date: Tue Jan 08 2019 - 03:06:42 EST


On Mon, Jan 07, 2019 at 07:56:47PM -0500, Lyude Paul wrote:
> Since I've had to fix two cases of drivers not checking the return code
> from this function, let's make the compiler complain so this doesn't
> come up again in the future.
>
> Signed-off-by: Lyude Paul <lyude@xxxxxxxxxx>
> Cc: Jerry Zuo <Jerry.Zuo@xxxxxxx>
> Cc: Daniel Vetter <daniel@xxxxxxxx>
> ---
> drivers/gpu/drm/drm_dp_mst_topology.c | 3 ++-
> include/drm/drm_dp_mst_helper.h | 3 ++-
> 2 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
> index 2ab16c9e6243..13a7e497bfe2 100644
> --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> @@ -2226,7 +2226,8 @@ EXPORT_SYMBOL(drm_dp_mst_topology_mgr_suspend);
> * if the device fails this returns -1, and the driver should do
> * a full MST reprobe, in case we were undocked.
> */
> -int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr)
> +int __must_check

I think you need the must_check only in the header. With that fixed:

Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>

> +drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr)
> {
> int ret = 0;
>
> diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
> index 371cc2816477..4355b55d0081 100644
> --- a/include/drm/drm_dp_mst_helper.h
> +++ b/include/drm/drm_dp_mst_helper.h
> @@ -614,7 +614,8 @@ void drm_dp_mst_dump_topology(struct seq_file *m,
> struct drm_dp_mst_topology_mgr *mgr);
>
> void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr);
> -int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr);
> +int __must_check
> +drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr);
> struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
> struct drm_dp_mst_topology_mgr *mgr);
> int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
> --
> 2.20.1
>

--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch