[PATCH v2 0/4] rust: DebugFS Bindings

[Matthew Maurer <mmaurer@google.com>]

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

This series currently only supports referencing `'static` lifetime
objects, because we need to know the objects outlive the DebugFS files.
A subsequent series may be able to relax this.

A few points that might be worth discussing on the API here:

1. The handles returned by directory and file creation currently remove
   themselves when they go out of scope. This behavior can be suppressed
   via `.keep()`. We could flip it to the other sense, and require that
   a returned handle be *explicitly* upconverted to get removed on drop.
   If we did this, we could consider making a different default for
   `subdir` vs `Dir::new`. The downside of doing this would be more
   complex types in the interface.
2. File creation currently returns a handle to preserve expressiveness
   (the ability to delete a file without deleting the directory it's
   in). I see (e.g. in ceph) explicit deletion of files, but this
   appears to be legacy code from before `recursive_remove` as opposed
   to wanting manual deletion. We could choose not to provide a handle
   here.

Signed-off-by: Matthew Maurer <mmaurer@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 (4):
      rust: debugfs: Bind DebugFS directory creation
      rust: debugfs: Bind file creation for long-lived Display
      rust: debugfs: Support format hooks
      rust: samples: Add debugfs sample

 MAINTAINERS                     |   2 +
 rust/bindings/bindings_helper.h |   1 +
 rust/kernel/debugfs.rs          | 345 ++++++++++++++++++++++++++++++++++++++++
 rust/kernel/lib.rs              |   1 +
 samples/rust/Kconfig            |  11 ++
 samples/rust/Makefile           |   1 +
 samples/rust/rust_debugfs.rs    |  37 +++++
 7 files changed, 398 insertions(+)
---
base-commit: b6a7783d306baf3150ac54cd5124f6e85dd375b0
change-id: 20250428-debugfs-rust-3cd5c97eb7d1

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