rust: pin-init: replace addr_of_mut! with &raw mut

`feature(raw_ref_op)` became stable in Rust 1.82.0 which is the current
MSRV of pin-init with no default features. Earlier Rust versions will
now need to enable `raw_ref_op` to continue to work with pin-init.

This reduces visual complexity and improves consistency with existing
reference syntax.

Suggested-by: Benno Lossin <lossin@kernel.org>
Link: Rust-for-Linux/linux#1148
Closes: Rust-for-Linux/pin-init#99
Signed-off-by: Antonio Hickey <contact@antoniohickey.com>
Link: Rust-for-Linux/pin-init@e277630
[ Reworded commit message. - Benno ]
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260319093542.3756606-6-lossin@kernel.org
Signed-off-by: Benno Lossin <lossin@kernel.org>

Author: antonio-hickey

rust/pin-init/README.md

@@ -160,7 +160,6 @@ actually does the initialization in the correct way. Here are the things to look
 ```rust
 use pin_init::{pin_data, pinned_drop, PinInit, PinnedDrop, pin_init_from_closure};
 use core::{
-    ptr::addr_of_mut,
     marker::PhantomPinned,
     cell::UnsafeCell,
     pin::Pin,
@@ -199,7 +198,7 @@ impl RawFoo {
         unsafe {
             pin_init_from_closure(move |slot: *mut Self| {
                 // `slot` contains uninit memory, avoid creating a reference.
-                let foo = addr_of_mut!((*slot).foo);
+                let foo = &raw mut (*slot).foo;
                 let foo = UnsafeCell::raw_get(foo).cast::<bindings::foo>();
 
                 // Initialize the `foo`

rust/pin-init/examples/big_struct_in_place.rs

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0 OR MIT
 
 #![cfg_attr(USE_RUSTC_FEATURES, feature(lint_reasons))]
+#![cfg_attr(USE_RUSTC_FEATURES, feature(raw_ref_op))]
 
 use pin_init::*;
 

rust/pin-init/examples/linked_list.rs

@@ -3,6 +3,7 @@
 #![allow(clippy::undocumented_unsafe_blocks)]
 #![cfg_attr(feature = "alloc", feature(allocator_api))]
 #![cfg_attr(USE_RUSTC_FEATURES, feature(lint_reasons))]
+#![cfg_attr(USE_RUSTC_FEATURES, feature(raw_ref_op))]
 
 use core::{
     cell::Cell,

rust/pin-init/examples/mutex.rs

@@ -3,6 +3,7 @@
 #![allow(clippy::undocumented_unsafe_blocks)]
 #![cfg_attr(feature = "alloc", feature(allocator_api))]
 #![cfg_attr(USE_RUSTC_FEATURES, feature(lint_reasons))]
+#![cfg_attr(USE_RUSTC_FEATURES, feature(raw_ref_op))]
 #![allow(clippy::missing_safety_doc)]
 
 use core::{

rust/pin-init/examples/pthread_mutex.rs

@@ -4,6 +4,7 @@
 #![allow(clippy::undocumented_unsafe_blocks)]
 #![cfg_attr(feature = "alloc", feature(allocator_api))]
 #![cfg_attr(USE_RUSTC_FEATURES, feature(lint_reasons))]
+#![cfg_attr(USE_RUSTC_FEATURES, feature(raw_ref_op))]
 
 #[cfg(not(windows))]
 mod pthread_mtx {

rust/pin-init/examples/static_init.rs

@@ -3,6 +3,7 @@
 #![allow(clippy::undocumented_unsafe_blocks)]
 #![cfg_attr(feature = "alloc", feature(allocator_api))]
 #![cfg_attr(USE_RUSTC_FEATURES, feature(lint_reasons))]
+#![cfg_attr(USE_RUSTC_FEATURES, feature(raw_ref_op))]
 #![allow(unused_imports)]
 
 use core::{

rust/pin-init/internal/src/init.rs

@@ -270,7 +270,7 @@ fn init_fields(
                     {
                         #value_prep
                         // SAFETY: TODO
-                        unsafe { #write(::core::ptr::addr_of_mut!((*#slot).#ident), #value_ident) };
+                        unsafe { #write(&raw mut (*#slot).#ident, #value_ident) };
                     }
                     #(#cfgs)*
                     #[allow(unused_variables)]
@@ -293,7 +293,7 @@ fn init_fields(
                             //   return when an error/panic occurs.
                             // - We also use `#data` to require the correct trait (`Init` or `PinInit`)
                             //   for `#ident`.
-                            unsafe { #data.#ident(::core::ptr::addr_of_mut!((*#slot).#ident), #init)? };
+                            unsafe { #data.#ident(&raw mut (*#slot).#ident, #init)? };
                         },
                         quote! {
                             // SAFETY: TODO
@@ -308,7 +308,7 @@ fn init_fields(
                             unsafe {
                                 ::pin_init::Init::__init(
                                     #init,
-                                    ::core::ptr::addr_of_mut!((*#slot).#ident),
+                                    &raw mut (*#slot).#ident,
                                 )?
                             };
                         },
@@ -348,7 +348,7 @@ fn init_fields(
                 // SAFETY: We forget the guard later when initialization has succeeded.
                 let #guard = unsafe {
                     ::pin_init::__internal::DropGuard::new(
-                        ::core::ptr::addr_of_mut!((*slot).#ident)
+                        &raw mut (*slot).#ident
                     )
                 };
             });

rust/pin-init/src/lib.rs

@@ -172,7 +172,6 @@
 //! # #![feature(extern_types)]
 //! use pin_init::{pin_data, pinned_drop, PinInit, PinnedDrop, pin_init_from_closure};
 //! use core::{
-//!     ptr::addr_of_mut,
 //!     marker::PhantomPinned,
 //!     cell::UnsafeCell,
 //!     pin::Pin,
@@ -211,7 +210,7 @@
 //!         unsafe {
 //!             pin_init_from_closure(move |slot: *mut Self| {
 //!                 // `slot` contains uninit memory, avoid creating a reference.
-//!                 let foo = addr_of_mut!((*slot).foo);
+//!                 let foo = &raw mut (*slot).foo;
 //!                 let foo = UnsafeCell::raw_get(foo).cast::<bindings::foo>();
 //!
 //!                 // Initialize the `foo`
@@ -265,6 +264,7 @@
 //! [Rust-for-Linux]: https://rust-for-linux.com/
 
 #![cfg_attr(USE_RUSTC_FEATURES, feature(lint_reasons))]
+#![cfg_attr(USE_RUSTC_FEATURES, feature(raw_ref_op))]
 #![cfg_attr(
     all(any(feature = "alloc", feature = "std"), USE_RUSTC_FEATURES),
     feature(new_uninit)
@@ -754,7 +754,7 @@ macro_rules! stack_try_pin_init {
 ///
 /// ```rust
 /// # use pin_init::*;
-/// # use core::{ptr::addr_of_mut, marker::PhantomPinned};
+/// # use core::marker::PhantomPinned;
 /// #[pin_data]
 /// #[derive(Zeroable)]
 /// struct Buf {
@@ -768,7 +768,7 @@ macro_rules! stack_try_pin_init {
 /// let init = pin_init!(&this in Buf {
 ///     buf: [0; 64],
 ///     // SAFETY: TODO.
-///     ptr: unsafe { addr_of_mut!((*this.as_ptr()).buf).cast() },
+///     ptr: unsafe { (&raw mut (*this.as_ptr()).buf).cast() },
 ///     pin: PhantomPinned,
 /// });
 /// let init = pin_init!(Buf {