drm/display/dp_mst: Don't validate port refs in drm_dp_check_and_send_link_address()

Drive-by cleanup, we don't need to validate the port references here as we
already previously went through the effort of refactoring things such that
we're guaranteed to be able to access ->mstb and ->port safely from
drm_dp_check_and_send_link_address(), since the only two places in the
codebase that drop an MST reference in such a way that it would remove it
from the topology are both protected under probe_lock.

Thanks for that, past Lyude!

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Wayne Lin <Wayne.Lin@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220602201757.30431-2-lyude@redhat.com

diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index a57f095..b546385 100644 (file)
--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
@@ -2667,24 +2667,14 @@ static int drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *mg
        }
 
        list_for_each_entry(port, &mstb->ports, next) {
-               struct drm_dp_mst_branch *mstb_child = NULL;
-
-               if (port->input || !port->ddps)
+               if (port->input || !port->ddps || !port->mstb)
                        continue;
 
-               if (port->mstb)
-                       mstb_child = drm_dp_mst_topology_get_mstb_validated(
-                           mgr, port->mstb);
-
-               if (mstb_child) {
-                       ret = drm_dp_check_and_send_link_address(mgr,
-                                                                mstb_child);
-                       drm_dp_mst_topology_put_mstb(mstb_child);
-                       if (ret == 1)
-                               changed = true;
-                       else if (ret < 0)
-                               return ret;
-               }
+               ret = drm_dp_check_and_send_link_address(mgr, port->mstb);
+               if (ret == 1)
+                       changed = true;
+               else if (ret < 0)
+                       return ret;
        }
 
        return changed;