drm/amd/display: Stop amdgpu_dm initialize when link nums greater than max_links

commit cf8b16857db702ceb8d52f9219a4613363e2b1cf upstream.

[Why]
Coverity report OVERRUN warning. There are
only max_links elements within dc->links. link
count could up to AMDGPU_DM_MAX_DISPLAY_INDEX 31.

[How]
Make sure link count less than max_links.

Reviewed-by: Harry Wentland <[email protected]>
Acked-by: Tom Chung <[email protected]>
Signed-off-by: Hersen Wu <[email protected]>
Tested-by: Daniel Wheeler <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>
[Minor conflict resolved due to code context change. And the macro MAX_LINKS
 is introduced by Commit 60df5628144b ("drm/amd/display: handle invalid
 connector indices") after 6.10. So here we still use the original array
 length MAX_PIPES * 2]
Signed-off-by: Jianqi Ren <[email protected]>
Signed-off-by: He Zhe <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: Hersen Wu

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -4499,17 +4499,17 @@ static int amdgpu_dm_initialize_drm_device(struct amdgpu_device *adev)
 		}
 	}
 
+	if (link_cnt > (MAX_PIPES * 2)) {
+		DRM_ERROR(
+			"KMS: Cannot support more than %d display indexes\n",
+				MAX_PIPES * 2);
+		goto fail;
+	}
+
 	/* loops over all connectors on the board */
 	for (i = 0; i < link_cnt; i++) {
 		struct dc_link *link = NULL;
 
-		if (i > AMDGPU_DM_MAX_DISPLAY_INDEX) {
-			DRM_ERROR(
-				"KMS: Cannot support more than %d display indexes\n",
-					AMDGPU_DM_MAX_DISPLAY_INDEX);
-			continue;
-		}
-
 		aconnector = kzalloc(sizeof(*aconnector), GFP_KERNEL);
 		if (!aconnector)
 			goto fail;