[PATCH 0/3] Rust block device driver API and null block driver

[Andreas Hindborg]

From: Andreas Hindborg <a.hindborg@xxxxxxxxxxx>

Hi All!

I am happy to finally send the first _non_ RFC patches for the Rust block device
API.

This series provides an initial Rust block layer device driver API, and a very
minimal null block driver to exercise the API. The driver has only one mode of
operation and cannot be configured.

These patches are an updated and trimmed down version of the v2 RFC [1]. One of
the requests for the v2 RFC was to split the abstractions into smaller pieces
that are easier to review. This is the first part of the split patches.

A notable change in this patch set is that they no longer use the `ref` field of
the C `struct request` to manage lifetime of the request structure.

The removed features will be sent later, as their dependencies land upstream.

As mentioned before, I will gladly maintain this code if required.

Canges from RFC v2:

- Change request state tracking method
- Use a slice rather than a raw pointer for `RawWriter`
- Use typestate patttern for `GenDisk` to prevent mutation of non synchronized fields
- Remove per gendisk  private data support
- Remove per tag_set private data support
- Remove per hwctx private data support
- Remove per request private data support
- Remove use of `ARef::into_raw`
- Remove use of `Opaque::try_ffi_init`
- Remove map_queues support
- Remove bio iteration support
- Remove methods to fail requests
- Remove request introspection methods
- Remove module configuration via module parameters
- Remove timer completion support for Rust null block driver
- Remove memory backing support for Rust null block driver
- Remove soft-irq completion support for Rust null block driver

Thanks for all the feedback and comments on the earlier versions!

Best regards,
Andreas Hindborg

Link: https://lore.kernel.org/all/20240313110515.70088-1-nmi@xxxxxxxxxxxx/ [1]

Andreas Hindborg (3):
  rust: block: introduce `kernel::block::mq` module
  rust: block: add rnull, Rust null_blk implementation
  MAINTAINERS: add entry for Rust block device driver API

 MAINTAINERS                        |  14 ++
 drivers/block/Kconfig              |   9 ++
 drivers/block/Makefile             |   3 +
 drivers/block/rnull.rs             |  82 ++++++++++
 rust/bindings/bindings_helper.h    |   2 +
 rust/helpers.c                     |  16 ++
 rust/kernel/block.rs               |   5 +
 rust/kernel/block/mq.rs            | 109 +++++++++++++
 rust/kernel/block/mq/gen_disk.rs   | 205 ++++++++++++++++++++++++
 rust/kernel/block/mq/operations.rs | 245 +++++++++++++++++++++++++++++
 rust/kernel/block/mq/raw_writer.rs |  55 +++++++
 rust/kernel/block/mq/request.rs    | 227 ++++++++++++++++++++++++++
 rust/kernel/block/mq/tag_set.rs    |  93 +++++++++++
 rust/kernel/error.rs               |   5 +
 rust/kernel/lib.rs                 |   2 +
 scripts/Makefile.build             |   2 +-
 16 files changed, 1073 insertions(+), 1 deletion(-)
 create mode 100644 drivers/block/rnull.rs
 create mode 100644 rust/kernel/block.rs
 create mode 100644 rust/kernel/block/mq.rs
 create mode 100644 rust/kernel/block/mq/gen_disk.rs
 create mode 100644 rust/kernel/block/mq/operations.rs
 create mode 100644 rust/kernel/block/mq/raw_writer.rs
 create mode 100644 rust/kernel/block/mq/request.rs
 create mode 100644 rust/kernel/block/mq/tag_set.rs


base-commit: fec50db7033ea478773b159e0e2efb135270e3b7
-- 
2.44.0