Claude review: drm/sched: Remove redundant entity->rq initialization and checks

[Claude Code Review Bot <claude-review@example.com>]

Patch Review

**sched_entity.c — removal of `entity->rq = NULL` in init:**

Correct. The function does `memset(entity, 0, sizeof(struct drm_sched_entity))` at line 125 (which already zeroes `rq`), and then immediately sets `entity->rq = &sched_list[0]->rq` at line 138. The explicit NULL assignment is doubly redundant.

**sched_entity.c — removal of `!entity->rq` check in `drm_sched_entity_kill()`:**

Correct. After successful init, `entity->rq` is always non-NULL, and no code path sets it to NULL afterwards (confirmed by grep — the only `entity->rq = NULL` in the scheduler was the one being removed in init).

**sched_entity.c — removal of `!entity->rq` check in `drm_sched_entity_flush()`:**

Correct, and the refactoring to move the `sched` variable initialization to the declaration is clean:

```c
-	struct drm_gpu_scheduler *sched;
+	struct drm_gpu_scheduler *sched =
+		container_of(entity->rq, typeof(*sched), rq);
```

This is safe since the early-return that guarded it is no longer needed.

**sched_main.c — removal of `!entity->rq` check in `drm_sched_job_init()`:**

Correct. As noted in the commit message, the error path's `dev_err(job->sched->dev, ...)` was buggy — `job->sched` is uninitialized at that point (only set in `drm_sched_job_arm()`), and even the `memset(job, 0, sizeof(*job))` runs *after* this check. If this dead code ever executed, it would dereference garbage memory rather than printing a useful diagnostic.

**Minor issue — stale kdoc:** The function comment for `drm_sched_job_init()` (lines 579–582 in the current tree) contains:

```c
 * WARNING: amdgpu abuses &drm_sched.ready to signal when the hardware
 * has died, which can mean that there's no valid runqueue for a @entity.
 * This function returns -ENOENT in this case (which probably should be -EIO as
 * a more meanigful return value).
```

After this patch, `drm_sched_job_init()` no longer returns `-ENOENT` at all. This WARNING should be removed or updated in the same patch to avoid a misleading kdoc comment.

**Verdict:** Patch is correct. The one piece of feedback is to also clean up the now-stale WARNING in the `drm_sched_job_init()` kdoc.

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