Claude review: drm/gem: Stop exposing the racy/unsafe drm_gem_lru_remove() helper

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

Patch Review

This patch removes the public `drm_gem_lru_remove()` function entirely and inlines a safe version in `drm_gem_object_release()`. The key insight: at `drm_gem_object_release()` time, refcount is zero, meaning no other code path can concurrently change `obj->lru`, so it's safe to read `obj->lru` without the LRU lock, then acquire the lock to remove.

```c
+	if (obj->lru) {
+		guard(mutex)(obj->lru->lock);
+		drm_gem_lru_remove_locked(obj);
+	}
```

The `guard(mutex)` usage is appropriate — the scope-based locking will release the mutex at the end of the enclosing block (the `if` block).

The `drm_gem_lru_remove_locked()` static function is moved from its original location (near the other LRU helpers) up to just before `drm_gem_object_release()` so it's available at the call site. This is a code motion, not a change.

The removal of the declaration from `drm_gem.h`:

```c
-void drm_gem_lru_remove(struct drm_gem_object *obj);
```

This is correct. After patch 1 removes the only panthor call site, and this patch removes the function definition and the call in `drm_gem_object_release()`, there are no remaining callers. The cover letter notes MSM is the only other user of `drm_gem_lru`, but MSM doesn't use `drm_gem_lru_remove()` — it uses `drm_gem_lru_move_tail()` to move objects between LRUs, which is the safe pattern.

**One observation about EXPORT_SYMBOL:** The patch removes the `EXPORT_SYMBOL(drm_gem_lru_remove)` line along with the function. This is correct — no out-of-tree users should depend on this racy API.

No issues found. Patch is correct and a good cleanup.

**Summary:** All three patches are well-reasoned, correctly fix real races, and the series ordering is logical. The Reviewed-by tags from the reporter are present. This series looks good to merge. The only thing I'd flag is ensuring MSM is tested or at least audited that it doesn't call `drm_gem_lru_remove()` anywhere — which the cover letter already addresses by CC'ing MSM maintainers.

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Generated by Claude Code Patch Reviewer