| Message ID | 20250416-ptr-as-ptr-v9-6-18ec29b1b1f3@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | rust: reduce `as` casts, enable related lints | expand |
On Wed, Apr 16, 2025 at 01:36:10PM -0400, Tamir Duberstein wrote: > In Rust 1.78.0, Clippy introduced the `ref_as_ptr` lint [1]: > > > Using `as` casts may result in silently changing mutability or type. > > While this doesn't eliminate unchecked `as` conversions, it makes such > conversions easier to scrutinize. It also has the slight benefit of > removing a degree of freedom on which to bikeshed. Thus apply the > changes and enable the lint -- no functional change intended. > > Link: https://rust-lang.github.io/rust-clippy/master/index.html#ref_as_ptr [1] > Suggested-by: Benno Lossin <benno.lossin@proton.me> > Link: https://lore.kernel.org/all/D8PGG7NTWB6U.3SS3A5LN4XWMN@proton.me/ > Reviewed-by: Benno Lossin <benno.lossin@proton.me> > Signed-off-by: Tamir Duberstein <tamird@gmail.com> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Thanks! Regards, Boqun > --- > Makefile | 1 + > rust/bindings/lib.rs | 1 + > rust/kernel/device_id.rs | 2 +- > rust/kernel/fs/file.rs | 2 +- > rust/kernel/str.rs | 4 ++-- > rust/kernel/uaccess.rs | 4 ++-- > rust/uapi/lib.rs | 1 + > 7 files changed, 9 insertions(+), 6 deletions(-) > > diff --git a/Makefile b/Makefile > index eb5a942241a2..2a16e02f26db 100644 > --- a/Makefile > +++ b/Makefile > @@ -485,6 +485,7 @@ export rust_common_flags := --edition=2021 \ > -Wclippy::no_mangle_with_rust_abi \ > -Wclippy::ptr_as_ptr \ > -Wclippy::ptr_cast_constness \ > + -Wclippy::ref_as_ptr \ > -Wclippy::undocumented_unsafe_blocks \ > -Wclippy::unnecessary_safety_comment \ > -Wclippy::unnecessary_safety_doc \ > diff --git a/rust/bindings/lib.rs b/rust/bindings/lib.rs > index b105a0d899cc..2b69016070c6 100644 > --- a/rust/bindings/lib.rs > +++ b/rust/bindings/lib.rs > @@ -27,6 +27,7 @@ > #[allow(dead_code)] > #[allow(clippy::cast_lossless)] > #[allow(clippy::ptr_as_ptr)] > +#[allow(clippy::ref_as_ptr)] > #[allow(clippy::undocumented_unsafe_blocks)] > mod bindings_raw { > // Manual definition for blocklisted types. > diff --git a/rust/kernel/device_id.rs b/rust/kernel/device_id.rs > index 4063f09d76d9..74b5db81231f 100644 > --- a/rust/kernel/device_id.rs > +++ b/rust/kernel/device_id.rs > @@ -136,7 +136,7 @@ impl<T: RawDeviceId, U, const N: usize> IdTable<T, U> for IdArray<T, U, N> { > fn as_ptr(&self) -> *const T::RawType { > // This cannot be `self.ids.as_ptr()`, as the return pointer must have correct provenance > // to access the sentinel. > - (self as *const Self).cast() > + core::ptr::from_ref(self).cast() > } > > fn id(&self, index: usize) -> &T::RawType { > diff --git a/rust/kernel/fs/file.rs b/rust/kernel/fs/file.rs > index 791f493ada10..c9a86beacb65 100644 > --- a/rust/kernel/fs/file.rs > +++ b/rust/kernel/fs/file.rs > @@ -364,7 +364,7 @@ fn deref(&self) -> &LocalFile { > // > // By the type invariants, there are no `fdget_pos` calls that did not take the > // `f_pos_lock` mutex. > - unsafe { LocalFile::from_raw_file((self as *const Self).cast()) } > + unsafe { LocalFile::from_raw_file(core::ptr::from_ref(self).cast()) } > } > } > > diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs > index 40034f77fc2f..ca173ae3282d 100644 > --- a/rust/kernel/str.rs > +++ b/rust/kernel/str.rs > @@ -29,7 +29,7 @@ pub const fn is_empty(&self) -> bool { > #[inline] > pub const fn from_bytes(bytes: &[u8]) -> &Self { > // SAFETY: `BStr` is transparent to `[u8]`. > - unsafe { &*(bytes as *const [u8] as *const BStr) } > + unsafe { &*(core::ptr::from_ref(bytes) as *const BStr) } > } > > /// Strip a prefix from `self`. Delegates to [`slice::strip_prefix`]. > @@ -290,7 +290,7 @@ pub const fn from_bytes_with_nul(bytes: &[u8]) -> Result<&Self, CStrConvertError > #[inline] > pub unsafe fn from_bytes_with_nul_unchecked_mut(bytes: &mut [u8]) -> &mut CStr { > // SAFETY: Properties of `bytes` guaranteed by the safety precondition. > - unsafe { &mut *(bytes as *mut [u8] as *mut CStr) } > + unsafe { &mut *(core::ptr::from_mut(bytes) as *mut CStr) } > } > > /// Returns a C pointer to the string. > diff --git a/rust/kernel/uaccess.rs b/rust/kernel/uaccess.rs > index 80a9782b1c6e..5f8e1e7babb3 100644 > --- a/rust/kernel/uaccess.rs > +++ b/rust/kernel/uaccess.rs > @@ -242,7 +242,7 @@ pub fn read_raw(&mut self, out: &mut [MaybeUninit<u8>]) -> Result { > pub fn read_slice(&mut self, out: &mut [u8]) -> Result { > // SAFETY: The types are compatible and `read_raw` doesn't write uninitialized bytes to > // `out`. > - let out = unsafe { &mut *(out as *mut [u8] as *mut [MaybeUninit<u8>]) }; > + let out = unsafe { &mut *(core::ptr::from_mut(out) as *mut [MaybeUninit<u8>]) }; > self.read_raw(out) > } > > @@ -357,7 +357,7 @@ pub fn write<T: AsBytes>(&mut self, value: &T) -> Result { > let res = unsafe { > bindings::_copy_to_user( > self.ptr as *mut c_void, > - (value as *const T).cast::<c_void>(), > + core::ptr::from_ref(value).cast::<c_void>(), > len, > ) > }; > diff --git a/rust/uapi/lib.rs b/rust/uapi/lib.rs > index d5dab4dfabec..6230ba48201d 100644 > --- a/rust/uapi/lib.rs > +++ b/rust/uapi/lib.rs > @@ -16,6 +16,7 @@ > clippy::all, > clippy::cast_lossless, > clippy::ptr_as_ptr, > + clippy::ref_as_ptr, > clippy::undocumented_unsafe_blocks, > dead_code, > missing_docs, > > -- > 2.49.0 >
On Wed, Apr 16, 2025 at 1:51 PM Boqun Feng <boqun.feng@gmail.com> wrote: > > On Wed, Apr 16, 2025 at 01:36:10PM -0400, Tamir Duberstein wrote: > > In Rust 1.78.0, Clippy introduced the `ref_as_ptr` lint [1]: > > > > > Using `as` casts may result in silently changing mutability or type. > > > > While this doesn't eliminate unchecked `as` conversions, it makes such > > conversions easier to scrutinize. It also has the slight benefit of > > removing a degree of freedom on which to bikeshed. Thus apply the > > changes and enable the lint -- no functional change intended. > > > > Link: https://rust-lang.github.io/rust-clippy/master/index.html#ref_as_ptr [1] > > Suggested-by: Benno Lossin <benno.lossin@proton.me> > > Link: https://lore.kernel.org/all/D8PGG7NTWB6U.3SS3A5LN4XWMN@proton.me/ > > Reviewed-by: Benno Lossin <benno.lossin@proton.me> > > Signed-off-by: Tamir Duberstein <tamird@gmail.com> > > Reviewed-by: Boqun Feng <boqun.feng@gmail.com> > > Thanks! Thank you! I updated the earlier patches as well.
On Wed, Apr 16, 2025 at 01:53:34PM -0400, Tamir Duberstein wrote: > On Wed, Apr 16, 2025 at 1:51 PM Boqun Feng <boqun.feng@gmail.com> wrote: > > > > On Wed, Apr 16, 2025 at 01:36:10PM -0400, Tamir Duberstein wrote: > > > In Rust 1.78.0, Clippy introduced the `ref_as_ptr` lint [1]: > > > > > > > Using `as` casts may result in silently changing mutability or type. > > > > > > While this doesn't eliminate unchecked `as` conversions, it makes such > > > conversions easier to scrutinize. It also has the slight benefit of > > > removing a degree of freedom on which to bikeshed. Thus apply the > > > changes and enable the lint -- no functional change intended. > > > > > > Link: https://rust-lang.github.io/rust-clippy/master/index.html#ref_as_ptr [1] > > > Suggested-by: Benno Lossin <benno.lossin@proton.me> > > > Link: https://lore.kernel.org/all/D8PGG7NTWB6U.3SS3A5LN4XWMN@proton.me/ > > > Reviewed-by: Benno Lossin <benno.lossin@proton.me> > > > Signed-off-by: Tamir Duberstein <tamird@gmail.com> > > > > Reviewed-by: Boqun Feng <boqun.feng@gmail.com> > > > > Thanks! > > Thank you! I updated the earlier patches as well. Yeah, those look good to me in a quick look, I do plan to take a deep look and provide Reviewed-bys later. Regards, Boqun
diff --git a/Makefile b/Makefile index eb5a942241a2..2a16e02f26db 100644 --- a/Makefile +++ b/Makefile @@ -485,6 +485,7 @@ export rust_common_flags := --edition=2021 \ -Wclippy::no_mangle_with_rust_abi \ -Wclippy::ptr_as_ptr \ -Wclippy::ptr_cast_constness \ + -Wclippy::ref_as_ptr \ -Wclippy::undocumented_unsafe_blocks \ -Wclippy::unnecessary_safety_comment \ -Wclippy::unnecessary_safety_doc \ diff --git a/rust/bindings/lib.rs b/rust/bindings/lib.rs index b105a0d899cc..2b69016070c6 100644 --- a/rust/bindings/lib.rs +++ b/rust/bindings/lib.rs @@ -27,6 +27,7 @@ #[allow(dead_code)] #[allow(clippy::cast_lossless)] #[allow(clippy::ptr_as_ptr)] +#[allow(clippy::ref_as_ptr)] #[allow(clippy::undocumented_unsafe_blocks)] mod bindings_raw { // Manual definition for blocklisted types. diff --git a/rust/kernel/device_id.rs b/rust/kernel/device_id.rs index 4063f09d76d9..74b5db81231f 100644 --- a/rust/kernel/device_id.rs +++ b/rust/kernel/device_id.rs @@ -136,7 +136,7 @@ impl<T: RawDeviceId, U, const N: usize> IdTable<T, U> for IdArray<T, U, N> { fn as_ptr(&self) -> *const T::RawType { // This cannot be `self.ids.as_ptr()`, as the return pointer must have correct provenance // to access the sentinel. - (self as *const Self).cast() + core::ptr::from_ref(self).cast() } fn id(&self, index: usize) -> &T::RawType { diff --git a/rust/kernel/fs/file.rs b/rust/kernel/fs/file.rs index 791f493ada10..c9a86beacb65 100644 --- a/rust/kernel/fs/file.rs +++ b/rust/kernel/fs/file.rs @@ -364,7 +364,7 @@ fn deref(&self) -> &LocalFile { // // By the type invariants, there are no `fdget_pos` calls that did not take the // `f_pos_lock` mutex. - unsafe { LocalFile::from_raw_file((self as *const Self).cast()) } + unsafe { LocalFile::from_raw_file(core::ptr::from_ref(self).cast()) } } } diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs index 40034f77fc2f..ca173ae3282d 100644 --- a/rust/kernel/str.rs +++ b/rust/kernel/str.rs @@ -29,7 +29,7 @@ pub const fn is_empty(&self) -> bool { #[inline] pub const fn from_bytes(bytes: &[u8]) -> &Self { // SAFETY: `BStr` is transparent to `[u8]`. - unsafe { &*(bytes as *const [u8] as *const BStr) } + unsafe { &*(core::ptr::from_ref(bytes) as *const BStr) } } /// Strip a prefix from `self`. Delegates to [`slice::strip_prefix`]. @@ -290,7 +290,7 @@ pub const fn from_bytes_with_nul(bytes: &[u8]) -> Result<&Self, CStrConvertError #[inline] pub unsafe fn from_bytes_with_nul_unchecked_mut(bytes: &mut [u8]) -> &mut CStr { // SAFETY: Properties of `bytes` guaranteed by the safety precondition. - unsafe { &mut *(bytes as *mut [u8] as *mut CStr) } + unsafe { &mut *(core::ptr::from_mut(bytes) as *mut CStr) } } /// Returns a C pointer to the string. diff --git a/rust/kernel/uaccess.rs b/rust/kernel/uaccess.rs index 80a9782b1c6e..5f8e1e7babb3 100644 --- a/rust/kernel/uaccess.rs +++ b/rust/kernel/uaccess.rs @@ -242,7 +242,7 @@ pub fn read_raw(&mut self, out: &mut [MaybeUninit<u8>]) -> Result { pub fn read_slice(&mut self, out: &mut [u8]) -> Result { // SAFETY: The types are compatible and `read_raw` doesn't write uninitialized bytes to // `out`. - let out = unsafe { &mut *(out as *mut [u8] as *mut [MaybeUninit<u8>]) }; + let out = unsafe { &mut *(core::ptr::from_mut(out) as *mut [MaybeUninit<u8>]) }; self.read_raw(out) } @@ -357,7 +357,7 @@ pub fn write<T: AsBytes>(&mut self, value: &T) -> Result { let res = unsafe { bindings::_copy_to_user( self.ptr as *mut c_void, - (value as *const T).cast::<c_void>(), + core::ptr::from_ref(value).cast::<c_void>(), len, ) }; diff --git a/rust/uapi/lib.rs b/rust/uapi/lib.rs index d5dab4dfabec..6230ba48201d 100644 --- a/rust/uapi/lib.rs +++ b/rust/uapi/lib.rs @@ -16,6 +16,7 @@ clippy::all, clippy::cast_lossless, clippy::ptr_as_ptr, + clippy::ref_as_ptr, clippy::undocumented_unsafe_blocks, dead_code, missing_docs,