linux.git/rust/kernel/bitfield.rs, branch v7.2-rc1 Linux kernel source tree rust: bitfield: mark `Debug` impl as `#[inline]` 2026-06-16T23:32:56+00:00 Gary Guo gary@garyguo.net 2026-06-11T19:05:54+00:00 f09d2312d1d44a8b8c9d3bfd33acfe930a6d8250 A `Debug` impl is for debugging and is normally not used, and therefore should ideally not be code-generated unless used. However, Rust has no way of knowing if a dependent crate is going to use the trait impl or not, so unless it is marked as `#[inline]`, it will be code-generated in the defining crate (as it is not generic). Mark the impl generated by bitfield macro `#[inline]`, so they do not stay in the binary unless used. This reduces nova-core.o .text by 17% (from 151922 bytes to 125676 bytes). Signed-off-by: Gary Guo <gary@garyguo.net> Fixes: b7b8b4ccdad4 ("rust: extract `bitfield!` macro from `register!`") Acked-by: Alexandre Courbot <acourbot@nvidia.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://patch.msgid.link/20260611190555.2298991-1-gary@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org> 
A `Debug` impl is for debugging and is normally not used, and therefore
should ideally not be code-generated unless used. However, Rust has no way
of knowing if a dependent crate is going to use the trait impl or not, so
unless it is marked as `#[inline]`, it will be code-generated in the
defining crate (as it is not generic).

Mark the impl generated by bitfield macro `#[inline]`, so they do not stay
in the binary unless used.

This reduces nova-core.o .text by 17% (from 151922 bytes to 125676 bytes).

Signed-off-by: Gary Guo <gary@garyguo.net>
Fixes: b7b8b4ccdad4 ("rust: extract `bitfield!` macro from `register!`")
Acked-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20260611190555.2298991-1-gary@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
rust: bitfield: Add KUnit tests for bitfield 2026-06-09T02:13:07+00:00 Joel Fernandes joelagnelf@nvidia.com 2026-06-06T12:43:05+00:00 7f502747bc0019acf40d620b50a98b62851fa0cc Add KUnit tests to make sure the macro is working correctly. The unit tests are put behind the new `RUST_BITFIELD_KUNIT_TEST` Kconfig option. Acked-by: Danilo Krummrich <dakr@kernel.org> Reviewed-by: Eliot Courtney <ecourtney@nvidia.com> Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com> [acourbot: - Use a consistent test axis where each test focuses on a single thing. - Rename members to generic name including range for readability. - Add test exercising `try_with`. - Add test checking that unallocated bits are left untouched. ] Co-developed-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Reviewed-by: Yury Norov <ynorov@nvidia.com> Link: https://patch.msgid.link/20260606-bitfield-v5-2-b92188820914@nvidia.com [ Prefixed test suite name with `rust_` as mentioned. Markdown-formatted a few comments with Markdown. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org> 
Add KUnit tests to make sure the macro is working correctly. The unit
tests are put behind the new `RUST_BITFIELD_KUNIT_TEST` Kconfig option.

Acked-by: Danilo Krummrich <dakr@kernel.org>
Reviewed-by: Eliot Courtney <ecourtney@nvidia.com>
Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
[acourbot:
- Use a consistent test axis where each test focuses on a single thing.
- Rename members to generic name including range for readability.
- Add test exercising `try_with`.
- Add test checking that unallocated bits are left untouched.
]
Co-developed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Yury Norov <ynorov@nvidia.com>
Link: https://patch.msgid.link/20260606-bitfield-v5-2-b92188820914@nvidia.com
[ Prefixed test suite name with `rust_` as mentioned. Markdown-formatted
  a few comments with Markdown. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
rust: extract `bitfield!` macro from `register!` 2026-06-09T02:12:51+00:00 Alexandre Courbot acourbot@nvidia.com 2026-06-06T12:43:04+00:00 b7b8b4ccdad45a59aafa5cfc32a51fe1ee5cb680 Extract the bitfield-defining part of the `register!` macro into an independent macro used to define bitfield types with bounds-checked accessors. Each field is represented as a `Bounded` of the appropriate bit width, ensuring field values are never silently truncated. Fields can optionally be converted to/from custom types, either fallibly or infallibly. Appropriate documentation is also added, and a MAINTAINERS entry created for the new module. Two minor fixups are also applied: the private accessors are inlined, and a couple of missing fully qualified types in the macro are fixed. Acked-by: Yury Norov <ynorov@nvidia.com> Acked-by: Danilo Krummrich <dakr@kernel.org> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Reviewed-by: Yury Norov <ynorov@nvidia.com> Link: https://patch.msgid.link/20260606-bitfield-v5-1-b92188820914@nvidia.com [ Added some more intra-doc links. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org> 
Extract the bitfield-defining part of the `register!` macro into an
independent macro used to define bitfield types with bounds-checked
accessors.

Each field is represented as a `Bounded` of the appropriate bit width,
ensuring field values are never silently truncated.

Fields can optionally be converted to/from custom types, either fallibly
or infallibly.

Appropriate documentation is also added, and a MAINTAINERS entry created
for the new module.

Two minor fixups are also applied: the private accessors are inlined,
and a couple of missing fully qualified types in the macro are fixed.

Acked-by: Yury Norov <ynorov@nvidia.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Yury Norov <ynorov@nvidia.com>
Link: https://patch.msgid.link/20260606-bitfield-v5-1-b92188820914@nvidia.com
[ Added some more intra-doc links. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>