[PATCH v2 4/4] rust: make `build_assert` module the home of related macros
From: Gary Guo <gary@kernel.org>
Date: 2026-03-16 15:08:30
Also in:
driver-core, lkml, rust-for-linux
Subsystem:
atomic infrastructure, device i/o & irq [rust], dma mapping & scatterlist api [rust], ethernet phy library [rust], locking primitives, rust, rust [num], rust [sync], the rest, xarray api [rust] · Maintainers:
Will Deacon, Peter Zijlstra, Boqun Feng, Danilo Krummrich, Alice Ryhl, Daniel Almeida, FUJITA Tomonori, Ingo Molnar, Miguel Ojeda, Alexandre Courbot, Gary Guo, Linus Torvalds, Tamir Duberstein, Andreas Hindborg
From: Gary Guo <gary@garyguo.net> Given the macro scoping rules, all macros are rendered 3 times, in the module, in the top-level of kernel crate, and in the prelude. Add `#[doc(no_inline)]` to the prelude so it just shows up as re-export. Add `#[doc(hidden)]` to the macro definition and `#[doc(inline)]` to the re-export inside `build_assert` module so the top-level items are hidden. Signed-off-by: Gary Guo <gary@garyguo.net> --- rust/kernel/build_assert.rs | 19 ++++++++++++------- rust/kernel/dma.rs | 6 ++++-- rust/kernel/io/resource.rs | 2 +- rust/kernel/ioctl.rs | 2 +- rust/kernel/net/phy/reg.rs | 8 +++++--- rust/kernel/num/bounded.rs | 2 +- rust/kernel/prelude.rs | 3 ++- rust/kernel/sync/atomic/predefine.rs | 3 +-- rust/kernel/sync/locked_by.rs | 2 +- rust/kernel/sync/refcount.rs | 8 +++++--- rust/kernel/xarray.rs | 6 ++++-- 11 files changed, 37 insertions(+), 24 deletions(-)
diff --git a/rust/kernel/build_assert.rs b/rust/kernel/build_assert.rs
index acdfcbeb73f3..5d671761c446 100644
--- a/rust/kernel/build_assert.rs
+++ b/rust/kernel/build_assert.rs@@ -61,15 +61,16 @@ //! symbols and linker errors, it is not developer friendly to debug, so it is recommended to avoid it //! and prefer other two assertions where possible. +#[doc(inline)] pub use crate::{ - build_assert, + build_assert_macro as build_assert, build_error, const_assert, static_assert, // }; #[doc(hidden)] -pub use build_error::build_error; +pub use build_error::build_error as build_error_fn; /// Static assert (i.e. compile-time assert). ///
@@ -105,6 +106,7 @@ /// static_assert!(f(40) == 42, "f(x) must add 2 to the given input."); /// ``` #[macro_export] +#[doc(hidden)] macro_rules! static_assert { ($condition:expr $(,$arg:literal)?) => { const _: () = ::core::assert!($condition $(,$arg)?);
@@ -133,6 +135,7 @@ macro_rules! static_assert { /// } /// ``` #[macro_export] +#[doc(hidden)] macro_rules! const_assert { ($condition:expr $(,$arg:literal)?) => { const { ::core::assert!($condition $(,$arg)?) };
@@ -157,12 +160,13 @@ macro_rules! const_assert { /// // foo(usize::MAX); // Fails to compile. /// ``` #[macro_export] +#[doc(hidden)] macro_rules! build_error { () => {{ - $crate::build_assert::build_error("") + $crate::build_assert::build_error_fn("") }}; ($msg:expr) => {{ - $crate::build_assert::build_error($msg) + $crate::build_assert::build_error_fn($msg) }}; }
@@ -196,15 +200,16 @@ macro_rules! build_error { /// const _: () = const_bar(2); /// ``` #[macro_export] -macro_rules! build_assert { +#[doc(hidden)] +macro_rules! build_assert_macro { ($cond:expr $(,)?) => {{ if !$cond { - $crate::build_assert::build_error(concat!("assertion failed: ", stringify!($cond))); + $crate::build_assert::build_error_fn(concat!("assertion failed: ", stringify!($cond))); } }}; ($cond:expr, $msg:expr) => {{ if !$cond { - $crate::build_assert::build_error($msg); + $crate::build_assert::build_error_fn($msg); } }}; }
diff --git a/rust/kernel/dma.rs b/rust/kernel/dma.rs
index a396f8435739..bef3f33cf2ea 100644
--- a/rust/kernel/dma.rs
+++ b/rust/kernel/dma.rs@@ -5,12 +5,14 @@ //! C header: [`include/linux/dma-mapping.h`](srctree/include/linux/dma-mapping.h) use crate::{ - bindings, build_assert, device, + bindings, + build_assert::build_assert, + device, device::{Bound, Core}, error::{to_result, Result}, prelude::*, sync::aref::ARef, - transmute::{AsBytes, FromBytes}, + transmute::{AsBytes, FromBytes}, // }; use core::ptr::NonNull;
diff --git a/rust/kernel/io/resource.rs b/rust/kernel/io/resource.rs
index b7ac9faf141d..9cb18ce1c479 100644
--- a/rust/kernel/io/resource.rs
+++ b/rust/kernel/io/resource.rs@@ -229,7 +229,7 @@ impl Flags { // Always inline to optimize out error path of `build_assert`. #[inline(always)] const fn new(value: u32) -> Self { - crate::build_assert!(value as u64 <= c_ulong::MAX as u64); + crate::build_assert::build_assert!(value as u64 <= c_ulong::MAX as u64); Flags(value as c_ulong) } }
diff --git a/rust/kernel/ioctl.rs b/rust/kernel/ioctl.rs
index 2fc7662339e5..5bb5b48cf949 100644
--- a/rust/kernel/ioctl.rs
+++ b/rust/kernel/ioctl.rs@@ -6,7 +6,7 @@ #![expect(non_snake_case)] -use crate::build_assert; +use crate::build_assert::build_assert; /// Build an ioctl number, analogous to the C macro of the same name. #[inline(always)]
diff --git a/rust/kernel/net/phy/reg.rs b/rust/kernel/net/phy/reg.rs
index a7db0064cb7d..80e22c264ea8 100644
--- a/rust/kernel/net/phy/reg.rs
+++ b/rust/kernel/net/phy/reg.rs@@ -9,9 +9,11 @@ //! defined in IEEE 802.3. use super::Device; -use crate::build_assert; -use crate::error::*; -use crate::uapi; +use crate::{ + build_assert::build_assert, + error::*, + uapi, // +}; mod private { /// Marker that a trait cannot be implemented outside of this crate
diff --git a/rust/kernel/num/bounded.rs b/rust/kernel/num/bounded.rs
index 54d0ce3ba595..c09abfab1ce2 100644
--- a/rust/kernel/num/bounded.rs
+++ b/rust/kernel/num/bounded.rs@@ -364,7 +364,7 @@ pub fn try_new(value: T) -> Option<Self> { // Always inline to optimize out error path of `build_assert`. #[inline(always)] pub fn from_expr(expr: T) -> Self { - crate::build_assert!( + crate::build_assert::build_assert!( fits_within(expr, N), "Requested value larger than maximal representable value." );
diff --git a/rust/kernel/prelude.rs b/rust/kernel/prelude.rs
index 6a54597fa0a2..baf8f6a94ea1 100644
--- a/rust/kernel/prelude.rs
+++ b/rust/kernel/prelude.rs@@ -29,7 +29,8 @@ pub use pin_init::{init, pin_data, pin_init, pinned_drop, InPlaceWrite, Init, PinInit, Zeroable}; -pub use super::{ +#[doc(no_inline)] +pub use crate::build_assert::{ build_assert, build_error, const_assert,
diff --git a/rust/kernel/sync/atomic/predefine.rs b/rust/kernel/sync/atomic/predefine.rs
index 67a0406d3ea4..77f4a5c91a80 100644
--- a/rust/kernel/sync/atomic/predefine.rs
+++ b/rust/kernel/sync/atomic/predefine.rs@@ -2,8 +2,7 @@ //! Pre-defined atomic types -use crate::static_assert; -use core::mem::{align_of, size_of}; +use crate::prelude::*; // Ensure size and alignment requirements are checked. static_assert!(size_of::<bool>() == size_of::<i8>());
diff --git a/rust/kernel/sync/locked_by.rs b/rust/kernel/sync/locked_by.rs
index 61f100a45b35..fb4a1430b3b4 100644
--- a/rust/kernel/sync/locked_by.rs
+++ b/rust/kernel/sync/locked_by.rs@@ -3,7 +3,7 @@ //! A wrapper for data protected by a lock that does not wrap it. use super::{lock::Backend, lock::Lock}; -use crate::build_assert; +use crate::build_assert::build_assert; use core::{cell::UnsafeCell, mem::size_of, ptr}; /// Allows access to some data to be serialised by a lock that does not wrap it.
diff --git a/rust/kernel/sync/refcount.rs b/rust/kernel/sync/refcount.rs
index 6c7ae8b05a0b..23a5d201f343 100644
--- a/rust/kernel/sync/refcount.rs
+++ b/rust/kernel/sync/refcount.rs@@ -4,9 +4,11 @@ //! //! C header: [`include/linux/refcount.h`](srctree/include/linux/refcount.h) -use crate::build_assert; -use crate::sync::atomic::Atomic; -use crate::types::Opaque; +use crate::{ + build_assert::build_assert, + sync::atomic::Atomic, + types::Opaque, // +}; /// Atomic reference counter. ///
diff --git a/rust/kernel/xarray.rs b/rust/kernel/xarray.rs
index a49d6db28845..50b9feca7f10 100644
--- a/rust/kernel/xarray.rs
+++ b/rust/kernel/xarray.rs@@ -5,10 +5,12 @@ //! C header: [`include/linux/xarray.h`](srctree/include/linux/xarray.h) use crate::{ - alloc, bindings, build_assert, + alloc, + bindings, + build_assert::build_assert, error::{Error, Result}, ffi::c_void, - types::{ForeignOwnable, NotThreadSafe, Opaque}, + types::{ForeignOwnable, NotThreadSafe, Opaque}, // }; use core::{iter, marker::PhantomData, pin::Pin, ptr::NonNull}; use pin_init::{pin_data, pin_init, pinned_drop, PinInit};
--
2.51.2