[PATCH v2 4/5] rust: enable `clippy::as_ptr_cast_mut` lint

Tamir Duberstein
2025-03-09T16:01:15Z

In Rust 1.66.0, Clippy introduced the `as_ptr_cast_mut` lint [1]:

> Since `as_ptr` takes a `&self`, the pointer won’t have write
> permissions unless interior mutability is used, making it unlikely
> that having it as a mutable pointer is correct.

There is only one affected callsite, and the change amounts to replacing
`as _` with `.cast_mut().cast()`. This doesn't change the semantics, but
is more descriptive of what's going on.

Apply this change and enable the lint -- no functional change intended.

Link: https://rust-lang.github.io/rust-clippy/master/index.html#as_ptr_cast_mut [1]
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
---
Makefile | 1 +
rust/kernel/devres.rs | 2 +-
2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index c62bae2b107b..bb15b86182a3 100644
--- a/Makefile
+++ b/Makefile
@@ -477,6 +477,7 @@ export rust_common_flags := --edition=2021 \
-Wrust_2018_idioms \
-Wunreachable_pub \
-Wclippy::all \
+ -Wclippy::as_ptr_cast_mut \
-Wclippy::ignored_unit_patterns \
-Wclippy::mut_mut \
-Wclippy::needless_bitwise_bool \
diff --git a/rust/kernel/devres.rs b/rust/kernel/devres.rs
index 3a9d998ec371..598001157293 100644
--- a/rust/kernel/devres.rs
+++ b/rust/kernel/devres.rs
@@ -143,7 +143,7 @@ fn remove_action(this: &Arc<Self>) {
bindings::devm_remove_action_nowarn(
this.dev.as_raw(),
Some(this.callback),
- this.as_ptr() as _,
+ this.as_ptr().cast_mut().cast(),
)
};

--
2.48.1