Claude review: drm: Make CONFIG_RUST_DRM_GEM_SHMEM_HELPER selectable from menuconfig

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

Patch Review

**Verdict: Adding `RUST` dependency is correct. Making it user-selectable is questionable.**

The change:
```diff
 config RUST_DRM_GEM_SHMEM_HELPER
-	bool
-	depends on DRM && MMU
+	bool "Rust GEM shmem helper functions"
+	depends on DRM && MMU && RUST
```

**Adding `depends on RUST`** — This is a correct fix. Rust code obviously cannot build without `CONFIG_RUST`. Good catch.

**Adding the description string to make it user-selectable** — This is problematic. The C counterpart `DRM_GEM_SHMEM_HELPER` is a hidden `tristate` with no description (line 262 of Kconfig: `tristate` with no prompt string). It follows the standard kernel pattern where helper/library Kconfig options are hidden and get enabled via `select` from the drivers that need them. Users don't manually enable helper code — drivers pull in what they need.

`RUST_DRM_GEM_SHMEM_HELPER` was designed to follow this same pattern: a hidden `bool` that a Rust DRM driver would `select`. Currently nothing selects it (no Rust DRM drivers in-tree yet), so making it user-selectable is presumably to allow testing. But this should be documented in the commit message — the current message doesn't explain *why* a user would want to manually enable a helper library that no driver uses.

If the intent is just testability, a better approach might be to keep it hidden and add a `RUST_DRM_KUNIT_TEST` or similar config that selects it, following the pattern used elsewhere in the kernel for testing infrastructure code.

**Additional concern:** The commit message says "Along side it's not dependent on rust" — this is grammatically unclear and should be "Additionally, it is not dependent on RUST" or similar. Minor, but commit messages are permanent documentation.

**Commit message nit:** The cover letter says "making it selectable from menuconfig" but doesn't explain the use case for a user manually enabling a helper library with no consumers.

---
Generated by Claude Code Patch Reviewer