[PATCH RESEND] rust: replace `build_assert!` with `const_assert!`
From: Mohamad Alsadhan <hidden>
Date: 2026-05-23 12:28:42
Also in:
lkml, rust-for-linux
Subsystem:
dma mapping & scatterlist api [rust], i2c subsystem [rust], locking primitives, rust, the rest, xarray api [rust] · Maintainers:
Danilo Krummrich, Igor Korotin, Peter Zijlstra, Ingo Molnar, Will Deacon, Boqun Feng, Miguel Ojeda, Linus Torvalds, Tamir Duberstein, Andreas Hindborg
Several Rust assertions currently use the `build_assert!` macro
despite their conditions only depending on type parameters or const
generics, not runtime values.
Replace these with the more appropriate `const_assert!` macro which
should trigger earlier in the compilation pipeline. This is possible
since commit 560a7a9b9 ("rust: add `const_assert!` macro").
These changes were identified by my PR to klint (see link), which
added a new lint that suggests to use stronger build-time assertion
forms when possible.
No functional change intended.
Link: https://github.com/Rust-for-Linux/klint/pull/14
Acked-by: Tamir Duberstein <tamird@kernel.org>
Signed-off-by: Mohamad Alsadhan <redacted>
---
rust/kernel/dma.rs | 4 ++--
rust/kernel/i2c.rs | 2 +-
rust/kernel/list/arc.rs | 2 +-
rust/kernel/sync/locked_by.rs | 8 ++++----
rust/kernel/xarray.rs | 4 ++--
5 files changed, 10 insertions(+), 10 deletions(-)
diff --git a/rust/kernel/dma.rs b/rust/kernel/dma.rs
index 909d56fd5..deacfc719 100644
--- a/rust/kernel/dma.rs
+++ b/rust/kernel/dma.rs@@ -5,7 +5,7 @@ //! C header: [`include/linux/dma-mapping.h`](srctree/include/linux/dma-mapping.h) use crate::{ - bindings, build_assert, device, + bindings, device, device::{Bound, Core}, error::{to_result, Result}, prelude::*,
@@ -401,7 +401,7 @@ pub fn alloc_attrs( gfp_flags: kernel::alloc::Flags, dma_attrs: Attrs, ) -> Result<CoherentAllocation<T>> { - build_assert!( + const_assert!( core::mem::size_of::<T>() > 0, "It doesn't make sense for the allocated type to be a ZST" );
diff --git a/rust/kernel/i2c.rs b/rust/kernel/i2c.rs
index 7b908f0c5..55b763189 100644
--- a/rust/kernel/i2c.rs
+++ b/rust/kernel/i2c.rs@@ -110,7 +110,7 @@ unsafe fn register( name: &'static CStr, module: &'static ThisModule, ) -> Result { - build_assert!( + const_assert!( T::ACPI_ID_TABLE.is_some() || T::OF_ID_TABLE.is_some() || T::I2C_ID_TABLE.is_some(), "At least one of ACPI/OF/Legacy tables must be present when registering an i2c driver" );
diff --git a/rust/kernel/list/arc.rs b/rust/kernel/list/arc.rs
index e10824239..b57cec64f 100644
--- a/rust/kernel/list/arc.rs
+++ b/rust/kernel/list/arc.rs@@ -252,7 +252,7 @@ pub fn pair_from_pin_unique<const ID2: u64>( where T: ListArcSafe<ID2>, { - build_assert!(ID != ID2); + const_assert!(ID != ID2); // SAFETY: We have a `UniqueArc`, so there is no `ListArc`. unsafe { <T as ListArcSafe<ID>>::on_create_list_arc_from_unique(unique.as_mut()) };
diff --git a/rust/kernel/sync/locked_by.rs b/rust/kernel/sync/locked_by.rs
index 61f100a45..5d043e661 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::const_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.
@@ -100,7 +100,7 @@ impl<T, U> LockedBy<T, U> { /// memory location*, the data becomes accessible again: none of this affects memory safety /// because in any case at most one thread (or CPU) can access the protected data at a time. pub fn new<B: Backend>(owner: &Lock<U, B>, data: T) -> Self { - build_assert!( + const_assert!( size_of::<Lock<U, B>>() > 0, "The lock type cannot be a ZST because it may be impossible to distinguish instances" );
@@ -126,7 +126,7 @@ pub fn access<'a>(&'a self, owner: &'a U) -> &'a T where T: Sync, { - build_assert!( + const_assert!( size_of::<U>() > 0, "`U` cannot be a ZST because `owner` wouldn't be unique" );
@@ -155,7 +155,7 @@ pub fn access<'a>(&'a self, owner: &'a U) -> &'a T /// Panics if `owner` is different from the data protected by the lock used in /// [`new`](LockedBy::new). pub fn access_mut<'a>(&'a self, owner: &'a mut U) -> &'a mut T { - build_assert!( + const_assert!( size_of::<U>() > 0, "`U` cannot be a ZST because `owner` wouldn't be unique" );
diff --git a/rust/kernel/xarray.rs b/rust/kernel/xarray.rs
index 46e5f4322..d4b3eac34 100644
--- a/rust/kernel/xarray.rs
+++ b/rust/kernel/xarray.rs@@ -5,7 +5,7 @@ //! C header: [`include/linux/xarray.h`](srctree/include/linux/xarray.h) use crate::{ - alloc, bindings, build_assert, + alloc, bindings, const_assert, error::{Error, Result}, ffi::c_void, types::{ForeignOwnable, NotThreadSafe, Opaque},
@@ -231,7 +231,7 @@ pub fn store( value: T, gfp: alloc::Flags, ) -> Result<Option<T>, StoreError<T>> { - build_assert!( + const_assert!( T::FOREIGN_ALIGN >= 4, "pointers stored in XArray must be 4-byte aligned" );
--
2.54.0