[PATCH v5 19/20] drm/dp_mst: Check payload count in drm_dp_mst_atomic_check()

[Daniel Vetter]

On Tue, Jan 08, 2019 at 07:35:16PM -0500, Lyude Paul wrote:
> It occurred to me that we never actually check this! So let's start
> doing that.
> 
> Signed-off-by: Lyude Paul <lyude at redhat.com>
> Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> Cc: David Airlie <airlied at redhat.com>
> Cc: Jerry Zuo <Jerry.Zuo at amd.com>
> Cc: Harry Wentland <harry.wentland at amd.com>
> Cc: Juston Li <juston.li at intel.com>

Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>

> ---
>  drivers/gpu/drm/drm_dp_mst_topology.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
> index fc778c6d487e..41cf814207bf 100644
> --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> @@ -3650,7 +3650,7 @@ drm_dp_mst_atomic_check_topology_state(struct drm_dp_mst_topology_mgr *mgr,
>  				       struct drm_dp_mst_topology_state *mst_state)
>  {
>  	struct drm_dp_vcpi_allocation *vcpi;
> -	int avail_slots = 63;
> +	int avail_slots = 63, payload_count = 0;
>  
>  	list_for_each_entry(vcpi, &mst_state->vcpis, next) {
>  		/* Releasing VCPI is always OK-even if the port is gone */
> @@ -3670,6 +3670,12 @@ drm_dp_mst_atomic_check_topology_state(struct drm_dp_mst_topology_mgr *mgr,
>  					 avail_slots + vcpi->vcpi);
>  			return -ENOSPC;
>  		}
> +
> +		if (++payload_count > mgr->max_payloads) {
> +			DRM_DEBUG_ATOMIC("[MST MGR:%p] state %p has too many payloads (max=%d)\n",
> +					 mgr, mst_state, mgr->max_payloads);
> +			return -EINVAL;
> +		}
>  	}
>  	DRM_DEBUG_ATOMIC("[MST MGR:%p] mst state %p VCPI avail=%d used=%d\n",
>  			 mgr, mst_state, avail_slots,
> -- 
> 2.20.1
> 

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