Re: [WIP PATCH 02/15] drm/dp_mst: Refactor drm_dp_update_payload_part1()

[Daniel Vetter]

On Thu, Dec 13, 2018 at 08:25:31PM -0500, Lyude Paul wrote:
> There should be no functional changes here

Would be good to explain what you did refactor here, instead of me trying
to reconstruct it from the patch. Especially pre-coffee that helps :-)
> 
> Signed-off-by: Lyude Paul <lyude@xxxxxxxxxx>
> Cc: Juston Li <juston.li@xxxxxxxxx>
> ---
>  drivers/gpu/drm/drm_dp_mst_topology.c | 71 ++++++++++++++++-----------
>  1 file changed, 42 insertions(+), 29 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
> index 9b1b5c9b1fa0..2ab16c9e6243 100644
> --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> @@ -1879,39 +1879,48 @@ int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
>  
>  	mutex_lock(&mgr->payload_lock);
>  	for (i = 0; i < mgr->max_payloads; i++) {
> +		struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i];
> +		struct drm_dp_payload *payload = &mgr->payloads[i];
> +
>  		/* solve the current payloads - compare to the hw ones
>  		   - update the hw view */
>  		req_payload.start_slot = cur_slots;
> -		if (mgr->proposed_vcpis[i]) {
> -			port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
> +		if (vcpi) {
> +			port = container_of(vcpi, struct drm_dp_mst_port,
> +					    vcpi);
>  			port = drm_dp_get_validated_port_ref(mgr, port);
>  			if (!port) {
>  				mutex_unlock(&mgr->payload_lock);
>  				return -EINVAL;
>  			}
> -			req_payload.num_slots = mgr->proposed_vcpis[i]->num_slots;
> -			req_payload.vcpi = mgr->proposed_vcpis[i]->vcpi;
> +			req_payload.num_slots = vcpi->num_slots;
> +			req_payload.vcpi = vcpi->vcpi;
>  		} else {
>  			port = NULL;
>  			req_payload.num_slots = 0;
>  		}
>  
> -		mgr->payloads[i].start_slot = req_payload.start_slot;
> +		payload->start_slot = req_payload.start_slot;
>  		/* work out what is required to happen with this payload */
> -		if (mgr->payloads[i].num_slots != req_payload.num_slots) {
> +		if (payload->num_slots != req_payload.num_slots) {
>  
>  			/* need to push an update for this payload */
>  			if (req_payload.num_slots) {
> -				drm_dp_create_payload_step1(mgr, mgr->proposed_vcpis[i]->vcpi, &req_payload);
> -				mgr->payloads[i].num_slots = req_payload.num_slots;
> -				mgr->payloads[i].vcpi = req_payload.vcpi;
> -			} else if (mgr->payloads[i].num_slots) {
> -				mgr->payloads[i].num_slots = 0;
> -				drm_dp_destroy_payload_step1(mgr, port, mgr->payloads[i].vcpi, &mgr->payloads[i]);
> -				req_payload.payload_state = mgr->payloads[i].payload_state;
> -				mgr->payloads[i].start_slot = 0;
> +				drm_dp_create_payload_step1(mgr, vcpi->vcpi,
> +							    &req_payload);
> +				payload->num_slots = req_payload.num_slots;
> +				payload->vcpi = req_payload.vcpi;
> +
> +			} else if (payload->num_slots) {
> +				payload->num_slots = 0;
> +				drm_dp_destroy_payload_step1(mgr, port,
> +							     payload->vcpi,
> +							     payload);
> +				req_payload.payload_state =
> +					payload->payload_state;
> +				payload->start_slot = 0;
>  			}
> -			mgr->payloads[i].payload_state = req_payload.payload_state;
> +			payload->payload_state = req_payload.payload_state;
>  		}
>  		cur_slots += req_payload.num_slots;
>  
> @@ -1920,22 +1929,26 @@ int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
>  	}
>  
>  	for (i = 0; i < mgr->max_payloads; i++) {
> -		if (mgr->payloads[i].payload_state == DP_PAYLOAD_DELETE_LOCAL) {
> -			DRM_DEBUG_KMS("removing payload %d\n", i);
> -			for (j = i; j < mgr->max_payloads - 1; j++) {
> -				memcpy(&mgr->payloads[j], &mgr->payloads[j + 1], sizeof(struct drm_dp_payload));
> -				mgr->proposed_vcpis[j] = mgr->proposed_vcpis[j + 1];
> -				if (mgr->proposed_vcpis[j] && mgr->proposed_vcpis[j]->num_slots) {
> -					set_bit(j + 1, &mgr->payload_mask);
> -				} else {
> -					clear_bit(j + 1, &mgr->payload_mask);
> -				}
> -			}
> -			memset(&mgr->payloads[mgr->max_payloads - 1], 0, sizeof(struct drm_dp_payload));
> -			mgr->proposed_vcpis[mgr->max_payloads - 1] = NULL;
> -			clear_bit(mgr->max_payloads, &mgr->payload_mask);
> +		if (mgr->payloads[i].payload_state != DP_PAYLOAD_DELETE_LOCAL)
> +			continue;
> +
> +		DRM_DEBUG_KMS("removing payload %d\n", i);
> +		for (j = i; j < mgr->max_payloads - 1; j++) {
> +			mgr->payloads[j] = mgr->payloads[j + 1];
> +			mgr->proposed_vcpis[j] = mgr->proposed_vcpis[j + 1];
>  
> +			if (mgr->proposed_vcpis[j] &&
> +			    mgr->proposed_vcpis[j]->num_slots) {
> +				set_bit(j + 1, &mgr->payload_mask);
> +			} else {
> +				clear_bit(j + 1, &mgr->payload_mask);
> +			}
>  		}
> +
> +		memset(&mgr->payloads[mgr->max_payloads - 1], 0,
> +		       sizeof(struct drm_dp_payload));
> +		mgr->proposed_vcpis[mgr->max_payloads - 1] = NULL;
> +		clear_bit(mgr->max_payloads, &mgr->payload_mask);

With the commit message improved to mention
- Add local variables in the first loop
- Early continue to reduce 1 indent in the 2nd loop

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

>  	}
>  	mutex_unlock(&mgr->payload_lock);
>  
> -- 
> 2.19.2
> 

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