linux.git/rust/kernel/alloc/kvec.rs, branch v7.3-rc2

rust: alloc: add Vec::zeroed method

2026-08-05T23:22:14+00:00

Add a constructor for kernel Vec that allocates a vector of a given length
with all elements zero-initialized. Memory is allocated with the __GFP_ZERO
flag, matching the existing KBox::zeroed() pattern.

Signed-off-by: Timur Tabi 
Reviewed-by: Alexandre Courbot 
Tested-by: Alexandre Courbot 
Link: https://patch.msgid.link/20260731201017.2580713-2-ttabi@nvidia.com
Co-developed-by: Danilo Krummrich 
Signed-off-by: Danilo Krummrich

rust: tests: add Kconfig for KUnit test

2026-06-08T00:30:33+00:00

There are 6 individual Rust KUnit test suites (plus the doctests one). All
the tests are compiled unconditionally now, which adds ~200 kB to the
kernel image for me on x86_64. As Rust matures, this bloating will
inevitably grow.

Add Kconfig.test which includes a RUST_KUNIT_TESTS menu, and all
individual tests under it.

As usual, new tests are all enabled if KUNIT_ALL_TESTS=y.

Suggested-by: Alice Ryhl 
Signed-off-by: Yury Norov 
Reviewed-by: David Gow 
Acked-by: Gary Guo 
Link: https://patch.msgid.link/20260417031531.315281-3-ynorov@nvidia.com
[ Fixed capitalization. Used singular for "API" for consistency.
  Reworded to clarify these are suites and that there exists
  the doctests one (which is the biggest at the moment by
  far). - Miguel ]
Signed-off-by: Miguel Ojeda

rust: alloc: cleanup doctest imports to "kernel vertical" style

2026-05-20T15:34:17+00:00

Change all imports in the alloc module's doctests to use the "kernel
vertical" import style [1].

While at it, drop imports that are automatically included in doctests.

Link: https://docs.kernel.org/rust/coding-guidelines.html#imports [1]
Reviewed-by: Eliot Courtney 
Link: https://patch.msgid.link/20260513190946.619810-2-dakr@kernel.org
Signed-off-by: Danilo Krummrich

rust: alloc: cleanup imports and use "kernel vertical" style

2026-05-20T15:34:17+00:00

Change all imports in the alloc module to use the "kernel vertical"
import style [1].

While at it, drop unnecessary imports covered by prelude::*.

Link: https://docs.kernel.org/rust/coding-guidelines.html#imports [1]
Reviewed-by: Eliot Courtney 
Link: https://patch.msgid.link/20260513190946.619810-1-dakr@kernel.org
Signed-off-by: Danilo Krummrich

rust: alloc: fix `Vec::extend_with` SAFETY comment

2026-05-12T12:00:20+00:00

Fix an incorrect operator in the SAFETY comment, changing `<` to `<=`,
since `Vec::reserve` guarantees capacity for exactly n additional elements,
so the equal case should be included.

Signed-off-by: Hsiu Che Yu 
Reviewed-by: Alexandre Courbot 
Fixes: 2aac4cd7dae3d ("rust: alloc: implement kernel `Vec` type")
Link: https://patch.msgid.link/18fc8eee2f057a6bfbcadae156d1d0b7c40d0077.1777111268.git.yu.whisper.personal@gmail.com
Signed-off-by: Danilo Krummrich

rust: alloc: add doc test for `Vec::extend_with`

2026-05-12T12:00:03+00:00

Add a doc test for `Vec::extend_with` demonstrating basic usage and the
zero-length case.

Signed-off-by: Hsiu Che Yu 
Reviewed-by: Alexandre Courbot 
Tested-by: Alexandre Courbot 
Link: https://patch.msgid.link/a02bc604cde78ba505441a5555400e6f575e8a8a.1777111268.git.yu.whisper.personal@gmail.com
Signed-off-by: Danilo Krummrich

rust: alloc: fix assert in `Vec::reserve` doc test

2026-05-12T11:56:12+00:00

The assert in the doctest used `>= 10`, which only checks that the
capacity can hold `additional` elements, ignoring the existing length
of `v`. The correct check should ensure there is room for `additional`
*extra* elements on top of what is already in the vector.

Fix the assert to use `>= v.len() + 10` so the example accurately
reflects the actual semantics of the function.

Reported-by: Miguel Ojeda 
Closes: https://lore.kernel.org/rust-for-linux/CANiq72nkXWhjK9iFRrhGtkMZGsvNE_zVsu4JnxaFRfxWL7RRdg@mail.gmail.com/
Fixes: 2aac4cd7dae3d ("rust: alloc: implement kernel `Vec` type")
Signed-off-by: Hsiu Che Yu 
Reviewed-by: Alice Ryhl 
Reviewed-by: Alexandre Courbot 
Link: https://patch.msgid.link/20260427-doctest-kvec-reserve-v1-1-0623abcd9c2e@gmail.com
Signed-off-by: Danilo Krummrich

rust: alloc: add KUnit tests for KVVec shrink_to

2026-02-27T05:37:53+00:00

Add comprehensive KUnit tests for the shrink_to method for KVVec.
The tests verify:
- Basic shrinking from multiple pages to fewer pages with data integrity
  preservation
- Empty vector shrinking to zero capacity
- No-op behavior when shrinking to a larger capacity than current
- Respect for min_capacity parameter when larger than vector length
These tests ensure that the shrinking logic correctly identifies when
memory can be reclaimed (by freeing at least one page) and that data
integrity is maintained throughout shrink operations.

Reviewed-by: Alice Ryhl 
Acked-by: Danilo Krummrich 
Signed-off-by: Shivam Kalra 
Link: https://patch.msgid.link/20260216-binder-shrink-vec-v3-v6-2-ece8e8593e53@zohomail.in
Signed-off-by: Greg Kroah-Hartman

rust: kvec: implement shrink_to for KVVec

2026-02-27T05:37:53+00:00

Implement shrink_to method specifically for `KVVec` (i.e.,
`Vec`). `shrink_to` reduces the vector's capacity to a
specified minimum.

For kmalloc-backed allocations, the method delegates to realloc(),
letting the allocator decide whether shrinking is worthwhile. For
vmalloc-backed allocations (detected via is_vmalloc_addr), shrinking
only occurs if at least one page of memory can be freed, using an
explicit alloc+copy+free since vrealloc does not yet support in-place
shrinking.

A TODO note marks this for future replacement with a generic shrink_to
for all allocators that uses A::realloc() once the underlying allocators
properly support shrinking via realloc.

Suggested-by: Alice Ryhl 
Suggested-by: Danilo Krummrich 
Reviewed-by: Alice Ryhl 
Acked-by: Danilo Krummrich 
Signed-off-by: Shivam Kalra 
Link: https://patch.msgid.link/20260216-binder-shrink-vec-v3-v6-1-ece8e8593e53@zohomail.in
Signed-off-by: Greg Kroah-Hartman

rust: alloc: employ a trailing comment to keep vertical layout

2025-10-16T22:56:20+00:00

Apply the formatting guidelines introduced in the previous commit to
make the file `rustfmt`-clean again.

Reviewed-by: Benno Lossin 
Signed-off-by: Miguel Ojeda