drm/amd/display: Check otg_master pointer before use it

Coverity highlighted that the parameter otg_master is referenced before
the if condition that validates it, which means that the code might have
some attempt to access a null pointer. This commit addresses this issue
by moving the pointer verification to the beginning of the function and
initializing all the values right after it.

Acked-by: Zaeem Mohamed <zaeem.mohamed@amd.com>
Signed-off-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_resource.c b/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
index 7894d3e52a2768d30ca9b77c218dca2b2dbb3c8d..e047ea4ff3aa16a3d7180819b789edf8775f98e8 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_resource.c
@@ -2077,15 +2077,23 @@ int resource_get_odm_slice_index(const struct pipe_ctx *pipe_ctx)
 int resource_get_odm_slice_dst_width(struct pipe_ctx *otg_master,
                bool is_last_segment)
 {
-       const struct dc_crtc_timing *timing = &otg_master->stream->timing;
-       int count = resource_get_odm_slice_count(otg_master);
-       int h_active = timing->h_addressable +
-                       timing->h_border_left +
-                       timing->h_border_right;
-       int width = h_active / count;
+       const struct dc_crtc_timing *timing;
+       int count;
+       int h_active;
+       int width;
        bool two_pixel_alignment_required = false;
 
-       if (otg_master && otg_master->stream_res.tg && otg_master->stream)
+       if (!otg_master || !otg_master->stream)
+               return 0;
+
+       timing = &otg_master->stream->timing;
+       count = resource_get_odm_slice_count(otg_master);
+       h_active = timing->h_addressable +
+                  timing->h_border_left +
+                  timing->h_border_right;
+       width = h_active / count;
+
+       if (otg_master->stream_res.tg && otg_master->stream)
                two_pixel_alignment_required = otg_master->stream_res.tg->funcs->is_two_pixels_per_container(timing);
 
        if ((width % 2) && two_pixel_alignment_required)