[PATCH 04/12] drm/amd/display: Add NULL-checks in dml2 assigned pipe search

[Roman.Li]

From: Allen Pan <allen....@amd.com>

[Why]
NULL-deref regression after:
"drm/amd/display: Fix dml2 assigned pipe search"

[How]
Add verification for potential NULLs

Fixes: 133e813d5044 ("drm/amd/display: Fix dml2 assigned pipe search")

Reviewed-by: Charlene Liu <charlene....@amd.com>
Reviewed-by: Nicholas Kazlauskas <nicholas.kazlaus...@amd.com>
Acked-by: Roman Li <roman...@amd.com>
Signed-off-by: Gabe Teeger <gabe.tee...@amd.com>
Signed-off-by: Allen Pan <allen....@amd.com>
---
 .../display/dc/dml2/dml2_dc_resource_mgmt.c   | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dml2/dml2_dc_resource_mgmt.c 
b/drivers/gpu/drm/amd/display/dc/dml2/dml2_dc_resource_mgmt.c
index a0ce681b26c6..a52c594e1ba4 100644
--- a/drivers/gpu/drm/amd/display/dc/dml2/dml2_dc_resource_mgmt.c
+++ b/drivers/gpu/drm/amd/display/dc/dml2/dml2_dc_resource_mgmt.c
@@ -146,19 +146,24 @@ static unsigned int find_pipes_assigned_to_plane(struct 
dml2_context *ctx,
        for (i = 0; i < ctx->config.dcn_pipe_count; i++) {
                struct pipe_ctx *pipe = &state->res_ctx.pipe_ctx[i];
 
-               if (!pipe->stream)
+               if (!pipe->plane_state || !pipe->stream)
                        continue;
 
                get_plane_id(ctx, state, pipe->plane_state, 
pipe->stream->stream_id,
                                        
ctx->v20.scratch.dml_to_dc_pipe_mapping.dml_pipe_idx_to_plane_index[pipe->pipe_idx],
                                        &plane_id_assigned_to_pipe);
-               if (pipe->plane_state && plane_id_assigned_to_pipe == plane_id 
&& !pipe->top_pipe && !pipe->prev_odm_pipe) {
+               if (plane_id_assigned_to_pipe == plane_id && 
!pipe->prev_odm_pipe
+                               && (!pipe->top_pipe || 
pipe->top_pipe->plane_state != pipe->plane_state)) {
                        while (pipe) {
-                               struct pipe_ctx *mpo_pipe = pipe;
-
-                               while (mpo_pipe) {
-                                       pipes[num_found++] = mpo_pipe->pipe_idx;
-                                       mpo_pipe = mpo_pipe->bottom_pipe;
+                               struct pipe_ctx *mpc_pipe = pipe;
+
+                               while (mpc_pipe) {
+                                       pipes[num_found++] = mpc_pipe->pipe_idx;
+                                       mpc_pipe = mpc_pipe->bottom_pipe;
+                                       if (!mpc_pipe)
+                                               break;
+                                       if (mpc_pipe->plane_state != 
pipe->plane_state)
+                                               mpc_pipe = NULL;
                                }
                                pipe = pipe->next_odm_pipe;
                        }
-- 
2.34.1