[PATCH v3 00/10] Allocation APIs

[Wedson Almeida Filho]

From: Wedson Almeida Filho <walmeida@xxxxxxxxxxxxx>

Revamp how we use the `alloc` crate.

We currently have a fork of the crate with changes to `Vec`; other
changes have been upstreamed (to the Rust project). This series removes
the fork and exposes all the functionality as extension traits.

Additionally, it also introduces allocation flag parameters to all
functions that may result in allocations (e.g., `Box::new`, `Arc::new`,
`Vec::push`, etc.) without the `try_` prefix -- the names are available
because we build `alloc` with `no_global_oom_handling`.

Lastly, the series also removes our reliance on the `allocator_api`
unstable feature.

Long term, we still want to make such functionality available in
upstream Rust, but this allows us to make progress now and reduces our
maintainance burden.

In summary:
1. Removes `alloc` fork
2. Removes use of `allocator_api` unstable feature
3. Introduces flags (e.g., GFP_KERNEL, GFP_ATOMIC) when allocating

---

Changes in v3:
- Rebased on top of the latest `rust-next` branch.
- Updated `krealloc_aligned` to use `Flags` instead of `bindings::gfp_t`.
- Added __GFP_ZERO to flags, as part of the previous change.
- Avoiding temporary stack value in `Box::new_uninit`.
- Implement `Box::new` using `Box::new_uninit` (so only one of them actually
  allocates).
- Added examples/tests to `VecExt` methods.
- Fixed bug in length in `extend_from_slice`
- Link to v2: https://lore.kernel.org/rust-for-linux/20240327023531.187880-1-wedsonaf@xxxxxxxxx/T/#t

Changes in v2:
- Updated description of `alloc` crate.
- Renamed vecext and boxext modules to vec_ext and box_ext.
- Added derive directive to `AllocError`.
- Updated safety comment in `BoxExt::new`.
- Updated `VecExt::push` and `VecExt::extend_from_slice` to use
  `spare_capacity_mut`
- Added directive to not compile `destructure` and `rebuild` when `test` or
  `testlib` are configured. Otherwise we have a warning because `push` and
  `extend_from_slice` don't use them anymore.
- Updated indentation in `Arc::new_uninit`
- Moved the removal of `TryReserveError` convesion to `Error` to patch 7, where
  usage of `TryReserveError` is actually removed.
- Link to v1: https://lore.kernel.org/rust-for-linux/20240325195418.166013-1-wedsonaf@xxxxxxxxx/T/#t

Wedson Almeida Filho (10):
  rust: kernel: move `allocator` module under `alloc`
  rust: alloc: introduce the `VecExt` trait
  kbuild: use the upstream `alloc` crate
  rust: alloc: remove our fork of the `alloc` crate
  rust: alloc: introduce allocation flags
  rust: alloc: introduce the `BoxExt` trait
  rust: alloc: update `VecExt` to take allocation flags
  rust: sync: update `Arc` and `UniqueArc` to take allocation flags
  rust: init: update `init` module to take allocation flags
  rust: kernel: remove usage of `allocator_api` unstable feature

 rust/Makefile                        |   16 +-
 rust/alloc/README.md                 |   36 -
 rust/alloc/alloc.rs                  |  452 ----
 rust/alloc/boxed.rs                  | 2463 -----------------
 rust/alloc/collections/mod.rs        |  160 --
 rust/alloc/lib.rs                    |  288 --
 rust/alloc/raw_vec.rs                |  611 -----
 rust/alloc/slice.rs                  |  890 -------
 rust/alloc/vec/drain.rs              |  255 --
 rust/alloc/vec/extract_if.rs         |  115 -
 rust/alloc/vec/into_iter.rs          |  454 ----
 rust/alloc/vec/is_zero.rs            |  204 --
 rust/alloc/vec/mod.rs                | 3683 --------------------------
 rust/alloc/vec/partial_eq.rs         |   49 -
 rust/alloc/vec/set_len_on_drop.rs    |   35 -
 rust/alloc/vec/spec_extend.rs        |  119 -
 rust/bindings/bindings_helper.h      |    3 +
 rust/kernel/alloc.rs                 |   74 +
 rust/kernel/{ => alloc}/allocator.rs |   17 +-
 rust/kernel/alloc/box_ext.rs         |   59 +
 rust/kernel/alloc/vec_ext.rs         |  176 ++
 rust/kernel/error.rs                 |   13 +-
 rust/kernel/init.rs                  |   57 +-
 rust/kernel/lib.rs                   |    5 +-
 rust/kernel/prelude.rs               |    2 +
 rust/kernel/str.rs                   |    6 +-
 rust/kernel/sync/arc.rs              |   50 +-
 rust/kernel/sync/condvar.rs          |    2 +-
 rust/kernel/sync/lock/mutex.rs       |    2 +-
 rust/kernel/sync/lock/spinlock.rs    |    2 +-
 rust/kernel/types.rs                 |    4 +-
 rust/kernel/workqueue.rs             |   14 +-
 samples/rust/rust_minimal.rs         |    6 +-
 samples/rust/rust_print.rs           |    4 +-
 scripts/generate_rust_analyzer.py    |    2 +-
 35 files changed, 405 insertions(+), 9923 deletions(-)
 delete mode 100644 rust/alloc/README.md
 delete mode 100644 rust/alloc/alloc.rs
 delete mode 100644 rust/alloc/boxed.rs
 delete mode 100644 rust/alloc/collections/mod.rs
 delete mode 100644 rust/alloc/lib.rs
 delete mode 100644 rust/alloc/raw_vec.rs
 delete mode 100644 rust/alloc/slice.rs
 delete mode 100644 rust/alloc/vec/drain.rs
 delete mode 100644 rust/alloc/vec/extract_if.rs
 delete mode 100644 rust/alloc/vec/into_iter.rs
 delete mode 100644 rust/alloc/vec/is_zero.rs
 delete mode 100644 rust/alloc/vec/mod.rs
 delete mode 100644 rust/alloc/vec/partial_eq.rs
 delete mode 100644 rust/alloc/vec/set_len_on_drop.rs
 delete mode 100644 rust/alloc/vec/spec_extend.rs
 create mode 100644 rust/kernel/alloc.rs
 rename rust/kernel/{ => alloc}/allocator.rs (86%)
 create mode 100644 rust/kernel/alloc/box_ext.rs
 create mode 100644 rust/kernel/alloc/vec_ext.rs


base-commit: 768409cff6cc89fe1194da880537a09857b6e4db
-- 
2.34.1