Merge tag 'rust-6.10' of https://github.com/Rust-for-Linux/linux

Pull Rust updates from Miguel Ojeda:
 "The most notable change is the drop of the 'alloc' in-tree fork. This
  is nicely reflected in the diffstat as a ~10k lines drop. In turn,
  this makes the version upgrades way simpler and smaller in the future,
  e.g. the latest one in commit 56f64b370612 ("rust: upgrade to Rust
  1.78.0").

  More importantly, this increases the chances that a newer compiler
  version just works, which in turn means supporting several compiler
  versions is easier now. Thus we will look into finally setting a
  minimum version in the near future.

  Toolchain and infrastructure:

   - Upgrade to Rust 1.78.0

     This time around, due to how the kernel and Rust schedules have
     aligned, there are two upgrades in fact. These allow us to remove
     one more unstable feature ('offset_of') from the list, among other
     improvements

   - Drop 'alloc' in-tree fork of the standard library crate, which
     means all the unstable features used by 'alloc' (~30 language ones,
     ~60 library ones) are not a concern anymore

   - Support DWARFv5 via the '-Zdwarf-version' flag

   - Support zlib and zstd debuginfo compression via the
     '-Zdebuginfo-compression' flag

  'kernel' crate:

   - Support allocation flags ('GFP_*'), particularly in 'Box' (via
     'BoxExt'), 'Vec' (via 'VecExt'), 'Arc' and 'UniqueArc', as well as
     in the 'init' module APIs

   - Remove usage of the 'allocator_api' unstable feature

   - Remove 'try_' prefix in allocation APIs' names

   - Add 'VecExt' (an extension trait) to be able to drop the 'alloc'
     fork

   - Add the '{make,to}_{upper,lower}case()' methods to 'CStr'/'CString'

   - Add the 'as_ptr' method to 'ThisModule'

   - Add the 'from_raw' method to 'ArcBorrow'

   - Add the 'into_unique_or_drop' method to 'Arc'

   - Display column number in the 'dbg!' macro output by applying the
     equivalent change done to the standard library one

   - Migrate 'Work' to '#[pin_data]' thanks to the changes in the
     'macros' crate, which allows to remove an unsafe call in its 'new'
     associated function

   - Prevent namespacing issues when using the '[try_][pin_]init!'
     macros by changing the generated name of guard variables

   - Make the 'get' method in 'Opaque' const

   - Implement the 'Default' trait for 'LockClassKey'

   - Remove unneeded 'kernel::prelude' imports from doctests

   - Remove redundant imports

  'macros' crate:

   - Add 'decl_generics' to 'parse_generics()' to support default
     values, and use that to allow them in '#[pin_data]'

  Helpers:

   - Trivial English grammar fix

  Documentation:

   - Add section on Rust Kselftests to the 'Testing' document

   - Expand the 'Abstractions vs. bindings' section of the 'General
     Information' document"

* tag 'rust-6.10' of https://github.com/Rust-for-Linux/linux: (31 commits)
  rust: alloc: fix dangling pointer in VecExt<T>::reserve()
  rust: upgrade to Rust 1.78.0
  rust: kernel: remove redundant imports
  rust: sync: implement `Default` for `LockClassKey`
  docs: rust: extend abstraction and binding documentation
  docs: rust: Add instructions for the Rust kselftest
  rust: remove unneeded `kernel::prelude` imports from doctests
  rust: update `dbg!()` to format column number
  rust: helpers: Fix grammar in comment
  rust: init: change the generated name of guard variables
  rust: sync: add `Arc::into_unique_or_drop`
  rust: sync: add `ArcBorrow::from_raw`
  rust: types: Make Opaque::get const
  rust: kernel: remove usage of `allocator_api` unstable feature
  rust: init: update `init` module to take allocation flags
  rust: sync: update `Arc` and `UniqueArc` to take allocation flags
  rust: alloc: update `VecExt` to take allocation flags
  rust: alloc: introduce the `BoxExt` trait
  rust: alloc: introduce allocation flags
  rust: alloc: remove our fork of the `alloc` crate
  ...

22 files changed, 677 insertions, 174 deletions

diff --git a/rust/kernel/alloc.rs b/rust/kernel/alloc.rs
new file mode 100644
index 000000000000..531b5e471cb1
--- /dev/null
+++ b/rust/kernel/alloc.rs
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Extensions to the [`alloc`] crate.
+
+#[cfg(not(test))]
+#[cfg(not(testlib))]
+mod allocator;
+pub mod box_ext;
+pub mod vec_ext;
+
+/// Indicates an allocation error.
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+pub struct AllocError;
+
+/// Flags to be used when allocating memory.
+///
+/// They can be combined with the operators `|`, `&`, and `!`.
+///
+/// Values can be used from the [`flags`] module.
+#[derive(Clone, Copy)]
+pub struct Flags(u32);
+
+impl core::ops::BitOr for Flags {
+    type Output = Self;
+    fn bitor(self, rhs: Self) -> Self::Output {
+        Self(self.0 | rhs.0)
+    }
+}
+
+impl core::ops::BitAnd for Flags {
+    type Output = Self;
+    fn bitand(self, rhs: Self) -> Self::Output {
+        Self(self.0 & rhs.0)
+    }
+}
+
+impl core::ops::Not for Flags {
+    type Output = Self;
+    fn not(self) -> Self::Output {
+        Self(!self.0)
+    }
+}
+
+/// Allocation flags.
+///
+/// These are meant to be used in functions that can allocate memory.
+pub mod flags {
+    use super::Flags;
+
+    /// Zeroes out the allocated memory.
+    ///
+    /// This is normally or'd with other flags.
+    pub const __GFP_ZERO: Flags = Flags(bindings::__GFP_ZERO);
+
+    /// Users can not sleep and need the allocation to succeed.
+    ///
+    /// A lower watermark is applied to allow access to "atomic reserves". The current
+    /// implementation doesn't support NMI and few other strict non-preemptive contexts (e.g.
+    /// raw_spin_lock). The same applies to [`GFP_NOWAIT`].
+    pub const GFP_ATOMIC: Flags = Flags(bindings::GFP_ATOMIC);
+
+    /// Typical for kernel-internal allocations. The caller requires ZONE_NORMAL or a lower zone
+    /// for direct access but can direct reclaim.
+    pub const GFP_KERNEL: Flags = Flags(bindings::GFP_KERNEL);
+
+    /// The same as [`GFP_KERNEL`], except the allocation is accounted to kmemcg.
+    pub const GFP_KERNEL_ACCOUNT: Flags = Flags(bindings::GFP_KERNEL_ACCOUNT);
+
+    /// Ror kernel allocations that should not stall for direct reclaim, start physical IO or
+    /// use any filesystem callback.  It is very likely to fail to allocate memory, even for very
+    /// small allocations.
+    pub const GFP_NOWAIT: Flags = Flags(bindings::GFP_NOWAIT);
+}
diff --git a/rust/kernel/allocator.rs b/rust/kernel/alloc/allocator.rs
index 01ad139e19bc..229642960cd1 100644
--- a/rust/kernel/allocator.rs
+++ b/rust/kernel/alloc/allocator.rs
@@ -2,11 +2,10 @@
 
 //! Allocator support.
 
+use super::{flags::*, Flags};
 use core::alloc::{GlobalAlloc, Layout};
 use core::ptr;
 
-use crate::bindings;
-
 struct KernelAllocator;
 
 /// Calls `krealloc` with a proper size to alloc a new object aligned to `new_layout`'s alignment.
@@ -15,7 +14,7 @@ struct KernelAllocator;
 ///
 /// - `ptr` can be either null or a pointer which has been allocated by this allocator.
 /// - `new_layout` must have a non-zero size.
-unsafe fn krealloc_aligned(ptr: *mut u8, new_layout: Layout, flags: bindings::gfp_t) -> *mut u8 {
+pub(crate) unsafe fn krealloc_aligned(ptr: *mut u8, new_layout: Layout, flags: Flags) -> *mut u8 {
     // Customized layouts from `Layout::from_size_align()` can have size < align, so pad first.
     let layout = new_layout.pad_to_align();
 
@@ -36,14 +35,14 @@ unsafe fn krealloc_aligned(ptr: *mut u8, new_layout: Layout, flags: bindings::gf
     //   function safety requirement.
     // - `size` is greater than 0 since it's either a `layout.size()` (which cannot be zero
     //   according to the function safety requirement) or a result from `next_power_of_two()`.
-    unsafe { bindings::krealloc(ptr as *const core::ffi::c_void, size, flags) as *mut u8 }
+    unsafe { bindings::krealloc(ptr as *const core::ffi::c_void, size, flags.0) as *mut u8 }
 }
 
 unsafe impl GlobalAlloc for KernelAllocator {
     unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
         // SAFETY: `ptr::null_mut()` is null and `layout` has a non-zero size by the function safety
         // requirement.
-        unsafe { krealloc_aligned(ptr::null_mut(), layout, bindings::GFP_KERNEL) }
+        unsafe { krealloc_aligned(ptr::null_mut(), layout, GFP_KERNEL) }
     }
 
     unsafe fn dealloc(&self, ptr: *mut u8, _layout: Layout) {
@@ -64,19 +63,13 @@ unsafe impl GlobalAlloc for KernelAllocator {
         //   requirement.
         // - the size of `layout` is not zero because `new_size` is not zero by the function safety
         //   requirement.
-        unsafe { krealloc_aligned(ptr, layout, bindings::GFP_KERNEL) }
+        unsafe { krealloc_aligned(ptr, layout, GFP_KERNEL) }
     }
 
     unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 {
         // SAFETY: `ptr::null_mut()` is null and `layout` has a non-zero size by the function safety
         // requirement.
-        unsafe {
-            krealloc_aligned(
-                ptr::null_mut(),
-                layout,
-                bindings::GFP_KERNEL | bindings::__GFP_ZERO,
-            )
-        }
+        unsafe { krealloc_aligned(ptr::null_mut(), layout, GFP_KERNEL | __GFP_ZERO) }
     }
 }
 
diff --git a/rust/kernel/alloc/box_ext.rs b/rust/kernel/alloc/box_ext.rs
new file mode 100644
index 000000000000..829cb1c1cf9e
--- /dev/null
+++ b/rust/kernel/alloc/box_ext.rs
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Extensions to [`Box`] for fallible allocations.
+
+use super::{AllocError, Flags};
+use alloc::boxed::Box;
+use core::mem::MaybeUninit;
+
+/// Extensions to [`Box`].
+pub trait BoxExt<T>: Sized {
+    /// Allocates a new box.
+    ///
+    /// The allocation may fail, in which case an error is returned.
+    fn new(x: T, flags: Flags) -> Result<Self, AllocError>;
+
+    /// Allocates a new uninitialised box.
+    ///
+    /// The allocation may fail, in which case an error is returned.
+    fn new_uninit(flags: Flags) -> Result<Box<MaybeUninit<T>>, AllocError>;
+}
+
+impl<T> BoxExt<T> for Box<T> {
+    fn new(x: T, flags: Flags) -> Result<Self, AllocError> {
+        let b = <Self as BoxExt<_>>::new_uninit(flags)?;
+        Ok(Box::write(b, x))
+    }
+
+    #[cfg(any(test, testlib))]
+    fn new_uninit(_flags: Flags) -> Result<Box<MaybeUninit<T>>, AllocError> {
+        Ok(Box::new_uninit())
+    }
+
+    #[cfg(not(any(test, testlib)))]
+    fn new_uninit(flags: Flags) -> Result<Box<MaybeUninit<T>>, AllocError> {
+        let ptr = if core::mem::size_of::<MaybeUninit<T>>() == 0 {
+            core::ptr::NonNull::<_>::dangling().as_ptr()
+        } else {
+            let layout = core::alloc::Layout::new::<MaybeUninit<T>>();
+
+            // SAFETY: Memory is being allocated (first arg is null). The only other source of
+            // safety issues is sleeping on atomic context, which is addressed by klint. Lastly,
+            // the type is not a SZT (checked above).
+            let ptr =
+                unsafe { super::allocator::krealloc_aligned(core::ptr::null_mut(), layout, flags) };
+            if ptr.is_null() {
+                return Err(AllocError);
+            }
+
+            ptr.cast::<MaybeUninit<T>>()
+        };
+
+        // SAFETY: For non-zero-sized types, we allocate above using the global allocator. For
+        // zero-sized types, we use `NonNull::dangling`.
+        Ok(unsafe { Box::from_raw(ptr) })
+    }
+}
diff --git a/rust/kernel/alloc/vec_ext.rs b/rust/kernel/alloc/vec_ext.rs
new file mode 100644
index 000000000000..e9a81052728a
--- /dev/null
+++ b/rust/kernel/alloc/vec_ext.rs
@@ -0,0 +1,182 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Extensions to [`Vec`] for fallible allocations.
+
+use super::{AllocError, Flags};
+use alloc::vec::Vec;
+use core::ptr;
+
+/// Extensions to [`Vec`].
+pub trait VecExt<T>: Sized {
+    /// Creates a new [`Vec`] instance with at least the given capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let v = Vec::<u32>::with_capacity(20, GFP_KERNEL)?;
+    ///
+    /// assert!(v.capacity() >= 20);
+    /// # Ok::<(), Error>(())
+    /// ```
+    fn with_capacity(capacity: usize, flags: Flags) -> Result<Self, AllocError>;
+
+    /// Appends an element to the back of the [`Vec`] instance.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut v = Vec::new();
+    /// v.push(1, GFP_KERNEL)?;
+    /// assert_eq!(&v, &[1]);
+    ///
+    /// v.push(2, GFP_KERNEL)?;
+    /// assert_eq!(&v, &[1, 2]);
+    /// # Ok::<(), Error>(())
+    /// ```
+    fn push(&mut self, v: T, flags: Flags) -> Result<(), AllocError>;
+
+    /// Pushes clones of the elements of slice into the [`Vec`] instance.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut v = Vec::new();
+    /// v.push(1, GFP_KERNEL)?;
+    ///
+    /// v.extend_from_slice(&[20, 30, 40], GFP_KERNEL)?;
+    /// assert_eq!(&v, &[1, 20, 30, 40]);
+    ///
+    /// v.extend_from_slice(&[50, 60], GFP_KERNEL)?;
+    /// assert_eq!(&v, &[1, 20, 30, 40, 50, 60]);
+    /// # Ok::<(), Error>(())
+    /// ```
+    fn extend_from_slice(&mut self, other: &[T], flags: Flags) -> Result<(), AllocError>
+    where
+        T: Clone;
+
+    /// Ensures that the capacity exceeds the length by at least `additional` elements.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut v = Vec::new();
+    /// v.push(1, GFP_KERNEL)?;
+    ///
+    /// v.reserve(10, GFP_KERNEL)?;
+    /// let cap = v.capacity();
+    /// assert!(cap >= 10);
+    ///
+    /// v.reserve(10, GFP_KERNEL)?;
+    /// let new_cap = v.capacity();
+    /// assert_eq!(new_cap, cap);
+    ///
+    /// # Ok::<(), Error>(())
+    /// ```
+    fn reserve(&mut self, additional: usize, flags: Flags) -> Result<(), AllocError>;
+}
+
+impl<T> VecExt<T> for Vec<T> {
+    fn with_capacity(capacity: usize, flags: Flags) -> Result<Self, AllocError> {
+        let mut v = Vec::new();
+        <Self as VecExt<_>>::reserve(&mut v, capacity, flags)?;
+        Ok(v)
+    }
+
+    fn push(&mut self, v: T, flags: Flags) -> Result<(), AllocError> {
+        <Self as VecExt<_>>::reserve(self, 1, flags)?;
+        let s = self.spare_capacity_mut();
+        s[0].write(v);
+
+        // SAFETY: We just initialised the first spare entry, so it is safe to increase the length
+        // by 1. We also know that the new length is <= capacity because of the previous call to
+        // `reserve` above.
+        unsafe { self.set_len(self.len() + 1) };
+        Ok(())
+    }
+
+    fn extend_from_slice(&mut self, other: &[T], flags: Flags) -> Result<(), AllocError>
+    where
+        T: Clone,
+    {
+        <Self as VecExt<_>>::reserve(self, other.len(), flags)?;
+        for (slot, item) in core::iter::zip(self.spare_capacity_mut(), other) {
+            slot.write(item.clone());
+        }
+
+        // SAFETY: We just initialised the `other.len()` spare entries, so it is safe to increase
+        // the length by the same amount. We also know that the new length is <= capacity because
+        // of the previous call to `reserve` above.
+        unsafe { self.set_len(self.len() + other.len()) };
+        Ok(())
+    }
+
+    #[cfg(any(test, testlib))]
+    fn reserve(&mut self, additional: usize, _flags: Flags) -> Result<(), AllocError> {
+        Vec::reserve(self, additional);
+        Ok(())
+    }
+
+    #[cfg(not(any(test, testlib)))]
+    fn reserve(&mut self, additional: usize, flags: Flags) -> Result<(), AllocError> {
+        let len = self.len();
+        let cap = self.capacity();
+
+        if cap - len >= additional {
+            return Ok(());
+        }
+
+        if core::mem::size_of::<T>() == 0 {
+            // The capacity is already `usize::MAX` for SZTs, we can't go higher.
+            return Err(AllocError);
+        }
+
+        // We know cap is <= `isize::MAX` because `Layout::array` fails if the resulting byte size
+        // is greater than `isize::MAX`. So the multiplication by two won't overflow.
+        let new_cap = core::cmp::max(cap * 2, len.checked_add(additional).ok_or(AllocError)?);
+        let layout = core::alloc::Layout::array::<T>(new_cap).map_err(|_| AllocError)?;
+
+        let (old_ptr, len, cap) = destructure(self);
+
+        // We need to make sure that `ptr` is either NULL or comes from a previous call to
+        // `krealloc_aligned`. A `Vec<T>`'s `ptr` value is not guaranteed to be NULL and might be
+        // dangling after being created with `Vec::new`. Instead, we can rely on `Vec<T>`'s capacity
+        // to be zero if no memory has been allocated yet.
+        let ptr = if cap == 0 { ptr::null_mut() } else { old_ptr };
+
+        // SAFETY: `ptr` is valid because it's either NULL or comes from a previous call to
+        // `krealloc_aligned`. We also verified that the type is not a ZST.
+        let new_ptr = unsafe { super::allocator::krealloc_aligned(ptr.cast(), layout, flags) };
+        if new_ptr.is_null() {
+            // SAFETY: We are just rebuilding the existing `Vec` with no changes.
+            unsafe { rebuild(self, old_ptr, len, cap) };
+            Err(AllocError)
+        } else {
+            // SAFETY: `ptr` has been reallocated with the layout for `new_cap` elements. New cap
+            // is greater than `cap`, so it continues to be >= `len`.
+            unsafe { rebuild(self, new_ptr.cast::<T>(), len, new_cap) };
+            Ok(())
+        }
+    }
+}
+
+#[cfg(not(any(test, testlib)))]
+fn destructure<T>(v: &mut Vec<T>) -> (*mut T, usize, usize) {
+    let mut tmp = Vec::new();
+    core::mem::swap(&mut tmp, v);
+    let mut tmp = core::mem::ManuallyDrop::new(tmp);
+    let len = tmp.len();
+    let cap = tmp.capacity();
+    (tmp.as_mut_ptr(), len, cap)
+}
+
+/// Rebuilds a `Vec` from a pointer, length, and capacity.
+///
+/// # Safety
+///
+/// The same as [`Vec::from_raw_parts`].
+#[cfg(not(any(test, testlib)))]
+unsafe fn rebuild<T>(v: &mut Vec<T>, ptr: *mut T, len: usize, cap: usize) {
+    // SAFETY: The safety requirements from this function satisfy those of `from_raw_parts`.
+    let mut tmp = unsafe { Vec::from_raw_parts(ptr, len, cap) };
+    core::mem::swap(&mut tmp, v);
+}
diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs
index 4786d3ee1e92..55280ae9fe40 100644
--- a/rust/kernel/error.rs
+++ b/rust/kernel/error.rs
@@ -4,14 +4,10 @@
 //!
 //! C header: [`include/uapi/asm-generic/errno-base.h`](srctree/include/uapi/asm-generic/errno-base.h)
 
-use crate::str::CStr;
+use crate::{alloc::AllocError, str::CStr};
 
-use alloc::{
-    alloc::{AllocError, LayoutError},
-    collections::TryReserveError,
-};
+use alloc::alloc::LayoutError;
 
-use core::convert::From;
 use core::fmt;
 use core::num::TryFromIntError;
 use core::str::Utf8Error;
@@ -192,12 +188,6 @@ impl From<Utf8Error> for Error {
     }
 }
 
-impl From<TryReserveError> for Error {
-    fn from(_: TryReserveError) -> Error {
-        code::ENOMEM
-    }
-}
-
 impl From<LayoutError> for Error {
     fn from(_: LayoutError) -> Error {
         code::ENOMEM
diff --git a/rust/kernel/init.rs b/rust/kernel/init.rs
index 09004b56fb65..68605b633e73 100644
--- a/rust/kernel/init.rs
+++ b/rust/kernel/init.rs
@@ -68,7 +68,7 @@
 //! #     a <- new_mutex!(42, "Foo::a"),
 //! #     b: 24,
 //! # });
-//! let foo: Result<Pin<Box<Foo>>> = Box::pin_init(foo);
+//! let foo: Result<Pin<Box<Foo>>> = Box::pin_init(foo, GFP_KERNEL);
 //! ```
 //!
 //! For more information see the [`pin_init!`] macro.
@@ -80,14 +80,15 @@
 //!
 //! ```rust
 //! # use kernel::sync::{new_mutex, Arc, Mutex};
-//! let mtx: Result<Arc<Mutex<usize>>> = Arc::pin_init(new_mutex!(42, "example::mtx"));
+//! let mtx: Result<Arc<Mutex<usize>>> =
+//!     Arc::pin_init(new_mutex!(42, "example::mtx"), GFP_KERNEL);
 //! ```
 //!
 //! To declare an init macro/function you just return an [`impl PinInit<T, E>`]:
 //!
 //! ```rust
 //! # #![allow(clippy::disallowed_names)]
-//! # use kernel::{sync::Mutex, prelude::*, new_mutex, init::PinInit, try_pin_init};
+//! # use kernel::{sync::Mutex, new_mutex, init::PinInit, try_pin_init};
 //! #[pin_data]
 //! struct DriverData {
 //!     #[pin]
@@ -99,7 +100,7 @@
 //!     fn new() -> impl PinInit<Self, Error> {
 //!         try_pin_init!(Self {
 //!             status <- new_mutex!(0, "DriverData::status"),
-//!             buffer: Box::init(kernel::init::zeroed())?,
+//!             buffer: Box::init(kernel::init::zeroed(), GFP_KERNEL)?,
 //!         })
 //!     }
 //! }
@@ -121,7 +122,7 @@
 //!
 //! ```rust
 //! # #![allow(unreachable_pub, clippy::disallowed_names)]
-//! use kernel::{prelude::*, init, types::Opaque};
+//! use kernel::{init, types::Opaque};
 //! use core::{ptr::addr_of_mut, marker::PhantomPinned, pin::Pin};
 //! # mod bindings {
 //! #     #![allow(non_camel_case_types)]
@@ -210,13 +211,13 @@
 //! [`pin_init!`]: crate::pin_init!
 
 use crate::{
+    alloc::{box_ext::BoxExt, AllocError, Flags},
     error::{self, Error},
     sync::UniqueArc,
     types::{Opaque, ScopeGuard},
 };
 use alloc::boxed::Box;
 use core::{
-    alloc::AllocError,
     cell::UnsafeCell,
     convert::Infallible,
     marker::PhantomData,
@@ -305,9 +306,9 @@ macro_rules! stack_pin_init {
 ///
 /// stack_try_pin_init!(let foo: Result<Pin<&mut Foo>, AllocError> = pin_init!(Foo {
 ///     a <- new_mutex!(42),
-///     b: Box::try_new(Bar {
+///     b: Box::new(Bar {
 ///         x: 64,
-///     })?,
+///     }, GFP_KERNEL)?,
 /// }));
 /// let foo = foo.unwrap();
 /// pr_info!("a: {}", &*foo.a.lock());
@@ -331,9 +332,9 @@ macro_rules! stack_pin_init {
 ///
 /// stack_try_pin_init!(let foo: Pin<&mut Foo> =? pin_init!(Foo {
 ///     a <- new_mutex!(42),
-///     b: Box::try_new(Bar {
+///     b: Box::new(Bar {
 ///         x: 64,
-///     })?,
+///     }, GFP_KERNEL)?,
 /// }));
 /// pr_info!("a: {}", &*foo.a.lock());
 /// # Ok::<_, AllocError>(())
@@ -390,7 +391,7 @@ macro_rules! stack_try_pin_init {
 ///     },
 /// });
 /// # initializer }
-/// # Box::pin_init(demo()).unwrap();
+/// # Box::pin_init(demo(), GFP_KERNEL).unwrap();
 /// ```
 ///
 /// Arbitrary Rust expressions can be used to set the value of a variable.
@@ -412,7 +413,7 @@ macro_rules! stack_try_pin_init {
 ///
 /// ```rust
 /// # #![allow(clippy::disallowed_names)]
-/// # use kernel::{init, pin_init, prelude::*, init::*};
+/// # use kernel::{init, pin_init, init::*};
 /// # use core::pin::Pin;
 /// # #[pin_data]
 /// # struct Foo {
@@ -460,7 +461,7 @@ macro_rules! stack_try_pin_init {
 /// #         })
 /// #     }
 /// # }
-/// let foo = Box::pin_init(Foo::new());
+/// let foo = Box::pin_init(Foo::new(), GFP_KERNEL);
 /// ```
 ///
 /// They can also easily embed it into their own `struct`s:
@@ -600,7 +601,7 @@ macro_rules! pin_init {
 /// impl BigBuf {
 ///     fn new() -> impl PinInit<Self, Error> {
 ///         try_pin_init!(Self {
-///             big: Box::init(init::zeroed())?,
+///             big: Box::init(init::zeroed(), GFP_KERNEL)?,
 ///             small: [0; 1024 * 1024],
 ///             ptr: core::ptr::null_mut(),
 ///         }? Error)
@@ -701,7 +702,7 @@ macro_rules! init {
 /// impl BigBuf {
 ///     fn new() -> impl Init<Self, Error> {
 ///         try_init!(Self {
-///             big: Box::init(zeroed())?,
+///             big: Box::init(zeroed(), GFP_KERNEL)?,
 ///             small: [0; 1024 * 1024],
 ///         }? Error)
 ///     }
@@ -1013,7 +1014,7 @@ pub fn uninit<T, E>() -> impl Init<MaybeUninit<T>, E> {
 ///
 /// ```rust
 /// use kernel::{error::Error, init::init_array_from_fn};
-/// let array: Box<[usize; 1_000]> = Box::init::<Error>(init_array_from_fn(|i| i)).unwrap();
+/// let array: Box<[usize; 1_000]> = Box::init::<Error>(init_array_from_fn(|i| i), GFP_KERNEL).unwrap();
 /// assert_eq!(array.len(), 1_000);
 /// ```
 pub fn init_array_from_fn<I, const N: usize, T, E>(
@@ -1057,7 +1058,7 @@ where
 /// ```rust
 /// use kernel::{sync::{Arc, Mutex}, init::pin_init_array_from_fn, new_mutex};
 /// let array: Arc<[Mutex<usize>; 1_000]> =
-///     Arc::pin_init(pin_init_array_from_fn(|i| new_mutex!(i))).unwrap();
+///     Arc::pin_init(pin_init_array_from_fn(|i| new_mutex!(i)), GFP_KERNEL).unwrap();
 /// assert_eq!(array.len(), 1_000);
 /// ```
 pub fn pin_init_array_from_fn<I, const N: usize, T, E>(
@@ -1115,7 +1116,7 @@ pub trait InPlaceInit<T>: Sized {
     /// type.
     ///
     /// If `T: !Unpin` it will not be able to move afterwards.
-    fn try_pin_init<E>(init: impl PinInit<T, E>) -> Result<Pin<Self>, E>
+    fn try_pin_init<E>(init: impl PinInit<T, E>, flags: Flags) -> Result<Pin<Self>, E>
     where
         E: From<AllocError>;
 
@@ -1123,7 +1124,7 @@ pub trait InPlaceInit<T>: Sized {
     /// type.
     ///
     /// If `T: !Unpin` it will not be able to move afterwards.
-    fn pin_init<E>(init: impl PinInit<T, E>) -> error::Result<Pin<Self>>
+    fn pin_init<E>(init: impl PinInit<T, E>, flags: Flags) -> error::Result<Pin<Self>>
     where
         Error: From<E>,
     {
@@ -1131,16 +1132,16 @@ pub trait InPlaceInit<T>: Sized {
         let init = unsafe {
             pin_init_from_closure(|slot| init.__pinned_init(slot).map_err(|e| Error::from(e)))
         };
-        Self::try_pin_init(init)
+        Self::try_pin_init(init, flags)
     }
 
     /// Use the given initializer to in-place initialize a `T`.
-    fn try_init<E>(init: impl Init<T, E>) -> Result<Self, E>
+    fn try_init<E>(init: impl Init<T, E>, flags: Flags) -> Result<Self, E>
     where
         E: From<AllocError>;
 
     /// Use the given initializer to in-place initialize a `T`.
-    fn init<E>(init: impl Init<T, E>) -> error::Result<Self>
+    fn init<E>(init: impl Init<T, E>, flags: Flags) -> error::Result<Self>
     where
         Error: From<E>,
     {
@@ -1148,17 +1149,17 @@ pub trait InPlaceInit<T>: Sized {
         let init = unsafe {
             init_from_closure(|slot| init.__pinned_init(slot).map_err(|e| Error::from(e)))
         };
-        Self::try_init(init)
+        Self::try_init(init, flags)
     }
 }
 
 impl<T> InPlaceInit<T> for Box<T> {
     #[inline]
-    fn try_pin_init<E>(init: impl PinInit<T, E>) -> Result<Pin<Self>, E>
+    fn try_pin_init<E>(init: impl PinInit<T, E>, flags: Flags) -> Result<Pin<Self>, E>
     where
         E: From<AllocError>,
     {
-        let mut this = Box::try_new_uninit()?;
+        let mut this = <Box<_> as BoxExt<_>>::new_uninit(flags)?;
         let slot = this.as_mut_ptr();
         // SAFETY: When init errors/panics, slot will get deallocated but not dropped,
         // slot is valid and will not be moved, because we pin it later.
@@ -1168,11 +1169,11 @@ impl<T> InPlaceInit<T> for Box<T> {
     }
 
     #[inline]
-    fn try_init<E>(init: impl Init<T, E>) -> Result<Self, E>
+    fn try_init<E>(init: impl Init<T, E>, flags: Flags) -> Result<Self, E>
     where
         E: From<AllocError>,
     {
-        let mut this = Box::try_new_uninit()?;
+        let mut this = <Box<_> as BoxExt<_>>::new_uninit(flags)?;
         let slot = this.as_mut_ptr();
         // SAFETY: When init errors/panics, slot will get deallocated but not dropped,
         // slot is valid.
@@ -1184,11 +1185,11 @@ impl<T> InPlaceInit<T> for Box<T> {
 
 impl<T> InPlaceInit<T> for UniqueArc<T> {
     #[inline]
-    fn try_pin_init<E>(init: impl PinInit<T, E>) -> Result<Pin<Self>, E>
+    fn try_pin_init<E>(init: impl PinInit<T, E>, flags: Flags) -> Result<Pin<Self>, E>
     where
         E: From<AllocError>,
     {
-        let mut this = UniqueArc::try_new_uninit()?;
+        let mut this = UniqueArc::new_uninit(flags)?;
         let slot = this.as_mut_ptr();
         // SAFETY: When init errors/panics, slot will get deallocated but not dropped,
         // slot is valid and will not be moved, because we pin it later.
@@ -1198,11 +1199,11 @@ impl<T> InPlaceInit<T> for UniqueArc<T> {
     }
 
     #[inline]
-    fn try_init<E>(init: impl Init<T, E>) -> Result<Self, E>
+    fn try_init<E>(init: impl Init<T, E>, flags: Flags) -> Result<Self, E>
     where
         E: From<AllocError>,
     {
-        let mut this = UniqueArc::try_new_uninit()?;
+        let mut this = UniqueArc::new_uninit(flags)?;
         let slot = this.as_mut_ptr();
         // SAFETY: When init errors/panics, slot will get deallocated but not dropped,
         // slot is valid.
diff --git a/rust/kernel/init/macros.rs b/rust/kernel/init/macros.rs
index cb6e61b6c50b..02ecedc4ae7a 100644
--- a/rust/kernel/init/macros.rs
+++ b/rust/kernel/init/macros.rs
@@ -250,7 +250,7 @@
 //!                     // error type is `Infallible`) we will need to drop this field if there
 //!                     // is an error later. This `DropGuard` will drop the field when it gets
 //!                     // dropped and has not yet been forgotten.
-//!                     let t = unsafe {
+//!                     let __t_guard = unsafe {
 //!                         ::pinned_init::__internal::DropGuard::new(::core::addr_of_mut!((*slot).t))
 //!                     };
 //!                     // Expansion of `x: 0,`:
@@ -261,14 +261,14 @@
 //!                         unsafe { ::core::ptr::write(::core::addr_of_mut!((*slot).x), x) };
 //!                     }
 //!                     // We again create a `DropGuard`.
-//!                     let x = unsafe {
+//!                     let __x_guard = unsafe {
 //!                         ::kernel::init::__internal::DropGuard::new(::core::addr_of_mut!((*slot).x))
 //!                     };
 //!                     // Since initialization has successfully completed, we can now forget
 //!                     // the guards. This is not `mem::forget`, since we only have
 //!                     // `&DropGuard`.
-//!                     ::core::mem::forget(x);
-//!                     ::core::mem::forget(t);
+//!                     ::core::mem::forget(__x_guard);
+//!                     ::core::mem::forget(__t_guard);
 //!                     // Here we use the type checker to ensure that every field has been
 //!                     // initialized exactly once, since this is `if false` it will never get
 //!                     // executed, but still type-checked.
@@ -461,16 +461,16 @@
 //!             {
 //!                 unsafe { ::core::ptr::write(::core::addr_of_mut!((*slot).a), a) };
 //!             }
-//!             let a = unsafe {
+//!             let __a_guard = unsafe {
 //!                 ::kernel::init::__internal::DropGuard::new(::core::addr_of_mut!((*slot).a))
 //!             };
 //!             let init = Bar::new(36);
 //!             unsafe { data.b(::core::addr_of_mut!((*slot).b), b)? };
-//!             let b = unsafe {
+//!             let __b_guard = unsafe {
 //!                 ::kernel::init::__internal::DropGuard::new(::core::addr_of_mut!((*slot).b))
 //!             };
-//!             ::core::mem::forget(b);
-//!             ::core::mem::forget(a);
+//!             ::c