[PATCH v7 0/6] rust: DebugFS Bindings

[Matthew Maurer <mmaurer@google.com>]

This series provides safe DebugFS bindings for Rust, with a sample
module using them.

Signed-off-by: Matthew Maurer <mmaurer@google.com>
---
Changes in v7:
- Rewrote `entry::Entry` -> `Entry`
- Use `c_int` and `c_void` from kernel prelude rather than core
- Removed unnecessary `display_open` cast
- Switched from `Deref` + an explicit box to `ForeignOwnable` for
  attaching owned data.
- Made `&'static` and `&'static mut` implement `ForeignOwnable`
- Swapped "driver" to "module" in sample code
- Link to v6: https://lore.kernel.org/r/20250618-debugfs-rust-v6-0-72cae211b133@google.com

Changes in v6:
- Replaced explicit lifetimes with children keeping their parents alive.
- Added support for attaching owned data.
- Removed recomendation to only keep root handles and handles you want
  to delete around.
- Refactored some code into separate files to improve clarity.
- Link to v5: https://lore.kernel.org/r/20250505-debugfs-rust-v5-0-3e93ce7bb76e@google.com

Changes in v5:
- Made Dir + File wrappers around Entry
- All functions return owning handles. To discard without drop, use
  `forget`. To keep a handle without drop, use `ManuallyDrop`.
- Fixed bugs around `not(CONFIG_DEBUG_FS)`
- Removed unnecessary `addr_of!`
- Link to v4: https://lore.kernel.org/r/20250502-debugfs-rust-v4-0-788a9c6c2e77@google.com

Changes in v4:
- Remove SubDir, replace with type-level constant.
- Add lifetime to Dir to prevent subdirectories and files from outliving
  their parents and triggering an Oops when accessed.
- Split unsafe blocks with two calls into two blocks
- Access `private` field through direct pointer dereference, avoiding
  creation of a reference to it.
- Notably not changed - owning/non-owning handle defaults. The best read
  I had from the thread was to continue with this mode, but I'm willing
  to change if need be.
- Comment changes
  - More comment markdown
  - Remove scopes from examples
  - Put `as_ptr` properties into a `# Guarantees` section.
- Link to v3: https://lore.kernel.org/r/20250501-debugfs-rust-v3-0-850869fab672@google.com

Changes in v3:
- Split `Dir` into `Dir`/`SubDir`/`File` to improve API.
- Add "." to end of all comments.
- Convert INVARIANT to # Invariants on types.
- Add backticks everywhere I found variables/types in my comments.
- Promoted invariant comment to doc comment.
- Extended sample commenting to make it clearer what is happening.
- Link to v2: https://lore.kernel.org/r/20250430-debugfs-rust-v2-0-2e8d3985812b@google.com

Changes in v2:
- Drop support for builder / pinned bindings in initial series
- Remove `ARef` usage to abstract the dentry nature of handles
- Remove error handling to discourage users from caring whether DebugFS
  is enabled.
- Support CONFIG_DEBUG_FS=n while leaving the API available
- Fixed mistaken decimal/octal mixup
- Doc/comment cleanup
- Link to v1: https://lore.kernel.org/r/20250429-debugfs-rust-v1-0-6b6e7cb7929f@google.com

---
Matthew Maurer (6):
      rust: debugfs: Bind DebugFS directory creation
      rust: debugfs: Bind file creation for long-lived Display
      rust: types: Support &'static and &'static mut ForeignOwnable
      rust: debugfs: Support arbitrary owned backing for File
      rust: debugfs: Support format hooks
      rust: samples: Add debugfs sample

 MAINTAINERS                         |   3 +
 rust/bindings/bindings_helper.h     |   1 +
 rust/kernel/debugfs.rs              | 268 ++++++++++++++++++++++++++++++++++++
 rust/kernel/debugfs/display_file.rs | 155 +++++++++++++++++++++
 rust/kernel/debugfs/entry.rs        |  66 +++++++++
 rust/kernel/lib.rs                  |   1 +
 rust/kernel/types.rs                |  58 ++++++++
 samples/rust/Kconfig                |  11 ++
 samples/rust/Makefile               |   1 +
 samples/rust/rust_debugfs.rs        |  76 ++++++++++
 10 files changed, 640 insertions(+)
---
base-commit: bd243cb5d922cc6343007a3f3918c8d1970541d2
change-id: 20250428-debugfs-rust-3cd5c97eb7d1

Best regards,
-- 
Matthew Maurer <mmaurer@google.com>