drm/amd/display: Fix potential null-deref in dm_resume

[Why]
Fixing smatch error:
dm_resume() error: we previously assumed 'aconnector->dc_link' could be null

[How]
Check if dc_link null at the beginning of the loop,
so further checks can be dropped.

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Wayne Lin <Wayne.Lin@amd.com>
Acked-by: Jasdeep Dhillon <jdhillon@amd.com>
Signed-off-by: Roman Li <roman.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 6099b07..79c9327 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -2739,12 +2739,14 @@ static int dm_resume(void *handle)
        drm_for_each_connector_iter(connector, &iter) {
                aconnector = to_amdgpu_dm_connector(connector);
 
+               if (!aconnector->dc_link)
+                       continue;
+
                /*
                 * this is the case when traversing through already created
                 * MST connectors, should be skipped
                 */
-               if (aconnector->dc_link &&
-                   aconnector->dc_link->type == dc_connection_mst_branch)
+               if (aconnector->dc_link->type == dc_connection_mst_branch)
                        continue;
 
                mutex_lock(&aconnector->hpd_lock);