Claude review: drm/ttm: Extract code for attempting allocation in a place

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

Patch Review

Good refactoring that cleanly separates allocation-at-a-place logic into `ttm_bo_alloc_at_place()`. The `struct ttm_bo_alloc_state` is well-designed for the extensions coming in later patches.

The return code semantics are well documented:

```c
+ * Returns:
+ * -EBUSY: No space available, but allocation should be retried with ttm_bo_evict_alloc.
+ * -ENOSPC: No space available, allocation should not be retried.
+ * -ERESTARTSYS: An interruptible sleep was interrupted by a signal.
```

The error handling translation in `ttm_bo_alloc_at_place` correctly maps `-EAGAIN` (charge failure) to either `-EBUSY` or `-ENOSPC` based on `may_evict`, and the caller handles all three cases (`-ENOSPC` → continue, `-EBUSY` → try evict, other → return). This is equivalent to the original inline code.

The movement of `limit_pool` from `ttm_bo_evict_walk` to `ttm_bo_alloc_state` (accessed via pointer) is a clean design that avoids duplication and sets up well for patch 6.

No issues.

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Generated by Claude Code Patch Reviewer