On Wed Aug 19, 2026 at 8:09 PM JST, Gary Guo wrote: > Implement a `transmute_unchecked/transmute` that checks size at > monomorphization time instead of type-checking time. This allows more cases > where we know that the size matches but this is not generically checkable. > > The signature is equivalent to the unstable `transmute_neo` function in the > standard library. A safe variant is provided to use with types implementing > `FromBytes` and `IntoBytes`. > > Existing users of `transmute_copy` to bypass size checks are converted. > > Signed-off-by: Gary Guo <[email protected]>
Reviewed-by: Alexandre Courbot <[email protected]> ... with a couple of minor nits below. <...> > diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs > index 4d5c96ddc49c..7225abc64084 100644 > --- a/rust/kernel/lib.rs > +++ b/rust/kernel/lib.rs > @@ -98,6 +98,7 @@ > pub mod kunit; > pub mod list; > pub mod maple_tree; > +pub mod mem; > pub mod miscdevice; > pub mod mm; > pub mod module; > diff --git a/rust/kernel/mem.rs b/rust/kernel/mem.rs > new file mode 100644 > index 000000000000..a0901cbe1b2d > --- /dev/null > +++ b/rust/kernel/mem.rs > @@ -0,0 +1,37 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +//! Basic utilities for dealing with memory, values, and types. > + > +use crate::prelude::*; > + > +/// Version of `transmute` that performs size check at monomorphization-time. > +/// > +/// Use this instead of [`core::mem::transmute`] when it is known that sizes > are identical but this > +/// cannot be proven by the compiler during type checking. > +/// > +/// The signature is equivalent after Rust standard library's unstable > `transmute_neo` and that of nit: "equivalent to Rust..."? > +/// [RFC 3844](https://github.com/rust-lang/rfcs/pull/3844). > +/// > +/// # Safety > +/// > +/// Same as [`core::mem::transmute`]. Let's add a short doctest for this new core function (and for `transmute` as well). > +#[inline(always)] I suspect we want `#[inline]` here in line with Sashiko's comment on patch 3.
