linux.git/rust/kernel/alloc/kvec.rs, branch v6.12.80

rust: alloc: add missing invariant in Vec::set_len()

2025-06-19T13:32:09+00:00

[ Upstream commit fb1bf1067de979c89ae33589e0466d6ce0dde204 ]

When setting a new length, we have to justify that the set length
represents the exact number of elements stored in the vector.

Reviewed-by: Benno Lossin 
Reported-by: Alice Ryhl 
Closes: https://lore.kernel.org/rust-for-linux/20250311-iov-iter-v1-4-f6c9134ea824@google.com
Fixes: 2aac4cd7dae3 ("rust: alloc: implement kernel `Vec` type")
Link: https://lore.kernel.org/r/20250315154436.65065-2-dakr@kernel.org
Signed-off-by: Danilo Krummrich 
Signed-off-by: Sasha Levin

rust: allow Rust 1.87.0's `clippy::ptr_eq` lint

2025-05-18T06:24:57+00:00

commit a39f3087092716f2bd531d6fdc20403c3dc2a879 upstream.

Starting with Rust 1.87.0 (expected 2025-05-15) [1], Clippy may expand
the `ptr_eq` lint, e.g.:

    error: use `core::ptr::eq` when comparing raw pointers
       --> rust/kernel/list.rs:438:12
        |
    438 |         if self.first == item {
        |            ^^^^^^^^^^^^^^^^^^ help: try: `core::ptr::eq(self.first, item)`
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ptr_eq
        = note: `-D clippy::ptr-eq` implied by `-D warnings`
        = help: to override `-D warnings` add `#[allow(clippy::ptr_eq)]`

It is expected that a PR to relax the lint will be backported [2] by
the time Rust 1.87.0 releases, since the lint was considered too eager
(at least by default) [3].

Thus allow the lint temporarily just in case.

Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs).
Link: https://github.com/rust-lang/rust-clippy/pull/14339 [1]
Link: https://github.com/rust-lang/rust-clippy/pull/14526 [2]
Link: https://github.com/rust-lang/rust-clippy/issues/14525 [3]
Link: https://lore.kernel.org/r/20250502140237.1659624-3-ojeda@kernel.org
[ Converted to `allow`s since backport was confirmed. - Miguel ]
Signed-off-by: Miguel Ojeda 
Signed-off-by: Greg Kroah-Hartman

rust: alloc: implement `collect` for `IntoIter`

2025-03-13T12:01:45+00:00

commit 93e602310f87b7b515b86a8f919cc0799387e5c3 upstream.

Currently, we can't implement `FromIterator`. There are a couple of
issues with this trait in the kernel, namely:

  - Rust's specialization feature is unstable. This prevents us to
    optimize for the special case where `I::IntoIter` equals `Vec`'s
    `IntoIter` type.
  - We also can't use `I::IntoIter`'s type ID either to work around this,
    since `FromIterator` doesn't require this type to be `'static`.
  - `FromIterator::from_iter` does return `Self` instead of
    `Result`, hence we can't properly handle allocation
    failures.
  - Neither `Iterator::collect` nor `FromIterator::from_iter` can handle
    additional allocation flags.

Instead, provide `IntoIter::collect`, such that we can at least convert
`IntoIter` into a `Vec` again.

Reviewed-by: Alice Ryhl 
Reviewed-by: Benno Lossin 
Signed-off-by: Danilo Krummrich 
Link: https://lore.kernel.org/r/20241004154149.93856-19-dakr@kernel.org
[ Added newline in documentation, changed case of section to be
  consistent with an existing one, fixed typo. - Miguel ]
Signed-off-by: Miguel Ojeda 
Signed-off-by: Greg Kroah-Hartman

rust: alloc: implement `IntoIterator` for `Vec`

2025-03-13T12:01:45+00:00

commit 1d1d223aa3b37c34271aefc2706340d0843bfcb2 upstream.

Implement `IntoIterator` for `Vec`, `Vec`'s `IntoIter` type, as well as
`Iterator` for `IntoIter`.

`Vec::into_iter` disassembles the `Vec` into its raw parts; additionally,
`IntoIter` keeps track of a separate pointer, which is incremented
correspondingly as the iterator advances, while the length, or the count
of elements, is decremented.

This also means that `IntoIter` takes the ownership of the backing
buffer and is responsible to drop the remaining elements and free the
backing buffer, if it's dropped.

Reviewed-by: Alice Ryhl 
Reviewed-by: Benno Lossin 
Reviewed-by: Gary Guo 
Signed-off-by: Danilo Krummrich 
Link: https://lore.kernel.org/r/20241004154149.93856-18-dakr@kernel.org
[ Fixed typos. - Miguel ]
Signed-off-by: Miguel Ojeda 
Signed-off-by: Greg Kroah-Hartman

rust: alloc: implement kernel `Vec` type

2025-03-13T12:01:45+00:00

commit 2aac4cd7dae3d7bb0e0ddec2561b2ee4cbe6c8f6 upstream.

`Vec` provides a contiguous growable array type with contents allocated
with the kernel's allocators (e.g. `Kmalloc`, `Vmalloc` or `KVmalloc`).

In contrast to Rust's stdlib `Vec` type, the kernel `Vec` type considers
the kernel's GFP flags for all appropriate functions, always reports
allocation failures through `Result<_, AllocError>` and remains
independent from unstable features.

[ This patch starts using a new unstable feature, `inline_const`, but
  it was stabilized in Rust 1.79.0, i.e. the next version after the
  minimum one, thus it will not be an issue. - Miguel ]

Reviewed-by: Benno Lossin 
Reviewed-by: Gary Guo 
Signed-off-by: Danilo Krummrich 
Link: https://lore.kernel.org/r/20241004154149.93856-17-dakr@kernel.org
[ Cleaned `rustdoc` unescaped backtick warning, added a couple more
  backticks elsewhere, fixed typos, sorted `feature`s, rewrapped
  documentation lines. - Miguel ]
Signed-off-by: Miguel Ojeda 
Signed-off-by: Greg Kroah-Hartman