On Wed, Apr 16, 2025 at 01:36:06PM -0400, Tamir Duberstein wrote: > In Rust 1.72.0, Clippy introduced the `ptr_cast_constness` lint [1]: > > > Though `as` casts between raw pointers are not terrible, > > `pointer::cast_mut` and `pointer::cast_const` are safer because they > > cannot accidentally cast the pointer to another type. > > There are only 2 affected sites: > - `*mut T as *const U as *mut U` becomes `(*mut T).cast()` > - `&self as *const Self as *mut Self` becomes > `core::ptr::from_ref(self).cast_mut()`. > > Apply these changes and enable the lint -- no functional change > intended. > > Link: > https://rust-lang.github.io/rust-clippy/master/index.html#ptr_cast_constness > [1] > Reviewed-by: Benno Lossin <benno.los...@proton.me> > Signed-off-by: Tamir Duberstein <tam...@gmail.com> > --- > Makefile | 1 + > rust/kernel/block/mq/request.rs | 4 ++-- > rust/kernel/dma.rs | 2 +- > 3 files changed, 4 insertions(+), 3 deletions(-) > > diff --git a/Makefile b/Makefile > index 5d2931344490..7b85b2a8d371 100644 > --- a/Makefile > +++ b/Makefile > @@ -481,6 +481,7 @@ export rust_common_flags := --edition=2021 \ > -Aclippy::needless_lifetimes \ > -Wclippy::no_mangle_with_rust_abi \ > -Wclippy::ptr_as_ptr \ > + -Wclippy::ptr_cast_constness \ > -Wclippy::undocumented_unsafe_blocks \ > -Wclippy::unnecessary_safety_comment \ > -Wclippy::unnecessary_safety_doc \ > diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs > index 4a5b7ec914ef..af5c9ac94f36 100644 > --- a/rust/kernel/block/mq/request.rs > +++ b/rust/kernel/block/mq/request.rs > @@ -69,7 +69,7 @@ pub(crate) unsafe fn aref_from_raw(ptr: *mut > bindings::request) -> ARef<Self> { > // INVARIANT: By the safety requirements of this function, > invariants are upheld. > // SAFETY: By the safety requirement of this function, we own a > // reference count that we can pass to `ARef`. > - unsafe { ARef::from_raw(NonNull::new_unchecked(ptr as *const Self as > *mut Self)) } > + unsafe { ARef::from_raw(NonNull::new_unchecked(ptr.cast())) } > } > > /// Notify the block layer that a request is going to be processed now. > @@ -155,7 +155,7 @@ pub(crate) fn wrapper_ref(&self) -> &RequestDataWrapper { > // the private data associated with this request is initialized and > // valid. The existence of `&self` guarantees that the private data > is > // valid as a shared reference. > - unsafe { Self::wrapper_ptr(self as *const Self as *mut > Self).as_ref() } > + unsafe { > Self::wrapper_ptr(core::ptr::from_ref(self).cast_mut()).as_ref() } > } > } > > diff --git a/rust/kernel/dma.rs b/rust/kernel/dma.rs > index f395d1a6fe48..43ecf3c2e860 100644 > --- a/rust/kernel/dma.rs > +++ b/rust/kernel/dma.rs > @@ -186,7 +186,7 @@ pub fn alloc_attrs( > dev: dev.into(), > dma_handle, > count, > - cpu_addr: ret.cast(), > + cpu_addr: ret.cast::<T>(),
Is this change necessary? The rest looks good to me. Regards, Boqun > dma_attrs, > }) > } > > -- > 2.49.0 >
