Re: [PATCH 09/26] drm/dp_mst: Remove huge conditional in drm_dp_mst_handle_up_req()

[Daniel Vetter]

On Wed, Jul 17, 2019 at 09:42:32PM -0400, Lyude Paul wrote:
> Which reduces indentation and makes this function more legible.

Indeed, nice one.

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


> 
> Cc: Juston Li <juston.li@xxxxxxxxx>
> Cc: Imre Deak <imre.deak@xxxxxxxxx>
> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> Cc: Harry Wentland <hwentlan@xxxxxxx>
> Signed-off-by: Lyude Paul <lyude@xxxxxxxxxx>
> ---
>  drivers/gpu/drm/drm_dp_mst_topology.c | 90 +++++++++++++--------------
>  1 file changed, 45 insertions(+), 45 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
> index 57c9c605ee17..b867a2e8f779 100644
> --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> @@ -3126,7 +3126,9 @@ static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
>  
>  static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
>  {
> -	int ret = 0;
> +	struct drm_dp_sideband_msg_req_body msg;
> +	struct drm_dp_mst_branch *mstb = NULL;
> +	bool seqno;
>  
>  	if (!drm_dp_get_one_sb_msg(mgr, true)) {
>  		memset(&mgr->up_req_recv, 0,
> @@ -3134,62 +3136,60 @@ static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
>  		return 0;
>  	}
>  
> -	if (mgr->up_req_recv.have_eomt) {
> -		struct drm_dp_sideband_msg_req_body msg;
> -		struct drm_dp_mst_branch *mstb = NULL;
> -		bool seqno;
> -
> -		if (!mgr->up_req_recv.initial_hdr.broadcast) {
> -			mstb = drm_dp_get_mst_branch_device(mgr,
> -							    mgr->up_req_recv.initial_hdr.lct,
> -							    mgr->up_req_recv.initial_hdr.rad);
> -			if (!mstb) {
> -				DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->up_req_recv.initial_hdr.lct);
> -				memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
> -				return 0;
> -			}
> -		}
> +	if (!mgr->up_req_recv.have_eomt)
> +		return 0;
>  
> -		seqno = mgr->up_req_recv.initial_hdr.seqno;
> -		drm_dp_sideband_parse_req(&mgr->up_req_recv, &msg);
> +	if (!mgr->up_req_recv.initial_hdr.broadcast) {
> +		mstb = drm_dp_get_mst_branch_device(mgr,
> +						    mgr->up_req_recv.initial_hdr.lct,
> +						    mgr->up_req_recv.initial_hdr.rad);
> +		if (!mstb) {
> +			DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->up_req_recv.initial_hdr.lct);
> +			memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
> +			return 0;
> +		}
> +	}
>  
> -		if (msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
> -			drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, msg.req_type, seqno, false);
> +	seqno = mgr->up_req_recv.initial_hdr.seqno;
> +	drm_dp_sideband_parse_req(&mgr->up_req_recv, &msg);
>  
> -			if (!mstb)
> -				mstb = drm_dp_get_mst_branch_device_by_guid(mgr, msg.u.conn_stat.guid);
> +	if (msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
> +		drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, msg.req_type, seqno, false);
>  
> -			if (!mstb) {
> -				DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->up_req_recv.initial_hdr.lct);
> -				memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
> -				return 0;
> -			}
> +		if (!mstb)
> +			mstb = drm_dp_get_mst_branch_device_by_guid(mgr, msg.u.conn_stat.guid);
>  
> -			drm_dp_update_port(mstb, &msg.u.conn_stat);
> +		if (!mstb) {
> +			DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->up_req_recv.initial_hdr.lct);
> +			memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
> +			return 0;
> +		}
>  
> -			DRM_DEBUG_KMS("Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: %d\n", msg.u.conn_stat.port_number, msg.u.conn_stat.legacy_device_plug_status, msg.u.conn_stat.displayport_device_plug_status, msg.u.conn_stat.message_capability_status, msg.u.conn_stat.input_port, msg.u.conn_stat.peer_device_type);
> -			drm_kms_helper_hotplug_event(mgr->dev);
> +		drm_dp_update_port(mstb, &msg.u.conn_stat);
>  
> -		} else if (msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
> -			drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, msg.req_type, seqno, false);
> -			if (!mstb)
> -				mstb = drm_dp_get_mst_branch_device_by_guid(mgr, msg.u.resource_stat.guid);
> +		DRM_DEBUG_KMS("Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: %d\n", msg.u.conn_stat.port_number, msg.u.conn_stat.legacy_device_plug_status, msg.u.conn_stat.displayport_device_plug_status, msg.u.conn_stat.message_capability_status, msg.u.conn_stat.input_port, msg.u.conn_stat.peer_device_type);
> +		drm_kms_helper_hotplug_event(mgr->dev);
>  
> -			if (!mstb) {
> -				DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->up_req_recv.initial_hdr.lct);
> -				memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
> -				return 0;
> -			}
> +	} else if (msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
> +		drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, msg.req_type, seqno, false);
> +		if (!mstb)
> +			mstb = drm_dp_get_mst_branch_device_by_guid(mgr, msg.u.resource_stat.guid);
>  
> -			DRM_DEBUG_KMS("Got RSN: pn: %d avail_pbn %d\n", msg.u.resource_stat.port_number, msg.u.resource_stat.available_pbn);
> +		if (!mstb) {
> +			DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->up_req_recv.initial_hdr.lct);
> +			memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
> +			return 0;
>  		}
>  
> -		if (mstb)
> -			drm_dp_mst_topology_put_mstb(mstb);
> -
> -		memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
> +		DRM_DEBUG_KMS("Got RSN: pn: %d avail_pbn %d\n", msg.u.resource_stat.port_number, msg.u.resource_stat.available_pbn);
>  	}
> -	return ret;
> +
> +	if (mstb)
> +		drm_dp_mst_topology_put_mstb(mstb);
> +
> +	memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
> +
> +	return 0;
>  }
>  
>  /**
> -- 
> 2.21.0
> 

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