rust: enable `clippy::ref_as_ptr` lint

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>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-6-f43b024581e8@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

1 files changed, 6 insertions, 14 deletions

diff --git a/rust/kernel/configfs.rs b/rust/kernel/configfs.rs
index bc8e15dcec18..1ddac786bd0d 100644
--- a/rust/kernel/configfs.rs
+++ b/rust/kernel/configfs.rs
@@ -426,7 +426,7 @@ where
     };
 
     const fn vtable_ptr() -> *const bindings::configfs_group_operations {
-        &Self::VTABLE as *const bindings::configfs_group_operations
+        &Self::VTABLE
     }
 }
 
@@ -464,7 +464,7 @@ where
     };
 
     const fn vtable_ptr() -> *const bindings::configfs_item_operations {
-        &Self::VTABLE as *const bindings::configfs_item_operations
+        &Self::VTABLE
     }
 }
 
@@ -476,7 +476,7 @@ impl<Data> ItemOperationsVTable<Subsystem<Data>, Data> {
     };
 
     const fn vtable_ptr() -> *const bindings::configfs_item_operations {
-        &Self::VTABLE as *const bindings::configfs_item_operations
+        &Self::VTABLE
     }
 }
 
@@ -717,11 +717,7 @@ impl<const N: usize, Data> AttributeList<N, Data> {
 
         // SAFETY: By function safety requirements, we have exclusive access to
         // `self` and the reference created below will be exclusive.
-        unsafe {
-            (&mut *self.0.get())[I] = (attribute as *const Attribute<ID, O, Data>)
-                .cast_mut()
-                .cast()
-        };
+        unsafe { (&mut *self.0.get())[I] = core::ptr::from_ref(attribute).cast_mut().cast() };
     }
 }
 
@@ -761,9 +757,7 @@ macro_rules! impl_item_type {
                         ct_owner: owner.as_ptr(),
                         ct_group_ops: GroupOperationsVTable::<Data, Child>::vtable_ptr().cast_mut(),
                         ct_item_ops: ItemOperationsVTable::<$tpe, Data>::vtable_ptr().cast_mut(),
-                        ct_attrs: (attributes as *const AttributeList<N, Data>)
-                            .cast_mut()
-                            .cast(),
+                        ct_attrs: core::ptr::from_ref(attributes).cast_mut().cast(),
                         ct_bin_attrs: core::ptr::null_mut(),
                     }),
                     _p: PhantomData,
@@ -780,9 +774,7 @@ macro_rules! impl_item_type {
                         ct_owner: owner.as_ptr(),
                         ct_group_ops: core::ptr::null_mut(),
                         ct_item_ops: ItemOperationsVTable::<$tpe, Data>::vtable_ptr().cast_mut(),
-                        ct_attrs: (attributes as *const AttributeList<N, Data>)
-                            .cast_mut()
-                            .cast(),
+                        ct_attrs: core::ptr::from_ref(attributes).cast_mut().cast(),
                         ct_bin_attrs: core::ptr::null_mut(),
                     }),
                     _p: PhantomData,