[PATCH resent] drm/amd/display: Fix exception handling in dm_validate_stream_and_context()

[Markus Elfring]

Date: Sat, 18 Mar 2023 16:21:32 +0100

The label “cleanup” was used to jump to another pointer check despite of
the detail in the implementation of the function 
“dm_validate_stream_and_context”
that it was determined already that corresponding variables contained
still null pointers.

1. Thus return directly if
   * a null pointer was passed for the function parameter “stream”
     or
   * a call of the function “dc_create_plane_state” failed.

2. Use a more appropriate label instead.

3. Delete two questionable checks.

4. Omit extra initialisations (for the variables “dc_state” and 
“dc_plane_state”)
   which became unnecessary with this refactoring.


This issue was detected by using the Coccinelle software.

Fixes: 5468c36d628524effbb89a9503eb1a2318804759 ("drm/amd/display: Filter 
Invalid 420 Modes for HDMI TMDS")
Signed-off-by: Markus Elfring <elfr...@users.sourceforge.net>
---
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 20 ++++++++-----------
 1 file changed, 8 insertions(+), 12 deletions(-)

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 eeaeca8b51f4..3086613f5f5d 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -6426,19 +6426,19 @@ static enum dc_status 
dm_validate_stream_and_context(struct dc *dc,
                                                struct dc_stream_state *stream)
 {
        enum dc_status dc_result = DC_ERROR_UNEXPECTED;
-       struct dc_plane_state *dc_plane_state = NULL;
-       struct dc_state *dc_state = NULL;
+       struct dc_plane_state *dc_plane_state;
+       struct dc_state *dc_state;

        if (!stream)
-               goto cleanup;
+               return dc_result;

        dc_plane_state = dc_create_plane_state(dc);
        if (!dc_plane_state)
-               goto cleanup;
+               return dc_result;

        dc_state = dc_create_state(dc);
        if (!dc_state)
-               goto cleanup;
+               goto release_plane_state;

        /* populate stream to plane */
        dc_plane_state->src_rect.height  = stream->src.height;
@@ -6475,13 +6475,9 @@ static enum dc_status 
dm_validate_stream_and_context(struct dc *dc,
        if (dc_result == DC_OK)
                dc_result = dc_validate_global_state(dc, dc_state, true);

-cleanup:
-       if (dc_state)
-               dc_release_state(dc_state);
-
-       if (dc_plane_state)
-               dc_plane_state_release(dc_plane_state);
-
+       dc_release_state(dc_state);
+release_plane_state:
+       dc_plane_state_release(dc_plane_state);
        return dc_result;
 }

--
2.40.0