[PATCH v2 14/33] rust: alloc: simplify with `NonNull::add()` now that it is stable

Miguel Ojeda
2026-04-05T23:56:04Z

Currently, we need to go through raw pointers and then re-create the
`NonNull` from the result of offsetting the raw pointer.

`feature(non_null_convenience)` [1] has been stabilized in Rust
1.80.0 [2], which is older than our new minimum Rust version
(Rust 1.85.0).

Thus, now that we bump the Rust minimum version, simplify using
`NonNull::add()` and clean the TODO note.

Link: https://github.com/rust-lang/rust/issues/117691 [1]
Link: https://github.com/rust-lang/rust/pull/124498 [2]
Reviewed-by: Tamir Duberstein <tamird@kernel.org>
Reviewed-by: Gary Guo <gary@garyguo.net>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
rust/kernel/alloc/allocator/iter.rs | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/rust/kernel/alloc/allocator/iter.rs b/rust/kernel/alloc/allocator/iter.rs
index 5759f86029b7..e0a70b7a744a 100644
--- a/rust/kernel/alloc/allocator/iter.rs
+++ b/rust/kernel/alloc/allocator/iter.rs
@@ -42,15 +42,9 @@ fn next(&mut self) -> Option<Self::Item> {
return None;
}

- // TODO: Use `NonNull::add()` instead, once the minimum supported compiler version is
- // bumped to 1.80 or later.
- //
// SAFETY: `offset` is in the interval `[0, (self.page_count() - 1) * page::PAGE_SIZE]`,
// hence the resulting pointer is guaranteed to be within the same allocation.
- let ptr = unsafe { self.buf.as_ptr().add(offset) };
-
- // SAFETY: `ptr` is guaranteed to be non-null given that it is derived from `self.buf`.
- let ptr = unsafe { NonNull::new_unchecked(ptr) };
+ let ptr = unsafe { self.buf.add(offset) };

// SAFETY:
// - `ptr` is a valid pointer to a `Vmalloc` allocation.
--
2.53.0