6.12-stable review patch. If anyone has any objections, please let me know.
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From: Danilo Krummrich dakr@kernel.org
commit e8c6ccdbcaaf31f26c0fffd4073edd0b0147cdc6 upstream.
Now that all existing `Box` users were moved to the kernel `Box` type, remove the `BoxExt` extension and all other related extensions.
Reviewed-by: Alice Ryhl aliceryhl@google.com Reviewed-by: Benno Lossin benno.lossin@proton.me Reviewed-by: Gary Guo gary@garyguo.net Signed-off-by: Danilo Krummrich dakr@kernel.org Link: https://lore.kernel.org/r/20241004154149.93856-14-dakr@kernel.org Signed-off-by: Miguel Ojeda ojeda@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- rust/kernel/alloc.rs | 1 rust/kernel/alloc/box_ext.rs | 89 ------------------------------------------- rust/kernel/init.rs | 46 ---------------------- rust/kernel/lib.rs | 1 rust/kernel/prelude.rs | 4 - rust/kernel/types.rs | 50 ------------------------ 6 files changed, 3 insertions(+), 188 deletions(-) delete mode 100644 rust/kernel/alloc/box_ext.rs
--- a/rust/kernel/alloc.rs +++ b/rust/kernel/alloc.rs @@ -4,7 +4,6 @@
#[cfg(not(any(test, testlib)))] pub mod allocator; -pub mod box_ext; pub mod kbox; pub mod vec_ext;
--- a/rust/kernel/alloc/box_ext.rs +++ /dev/null @@ -1,89 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 - -//! Extensions to [`Box`] for fallible allocations. - -use super::{AllocError, Flags}; -use alloc::boxed::Box; -use core::{mem::MaybeUninit, ptr, result::Result}; - -/// 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>; - - /// Drops the contents, but keeps the allocation. - /// - /// # Examples - /// - /// ``` - /// use kernel::alloc::{flags, box_ext::BoxExt}; - /// let value = Box::new([0; 32], flags::GFP_KERNEL)?; - /// assert_eq!(*value, [0; 32]); - /// let mut value = Box::drop_contents(value); - /// // Now we can re-use `value`: - /// value.write([1; 32]); - /// // SAFETY: We just wrote to it. - /// let value = unsafe { value.assume_init() }; - /// assert_eq!(*value, [1; 32]); - /// # Ok::<(), Error>(()) - /// ``` - fn drop_contents(this: Self) -> Box<MaybeUninit<T>>; -} - -impl<T> BoxExt<T> for Box<T> { - fn new(x: T, flags: Flags) -> Result<Self, AllocError> { - let mut b = <Self as BoxExt<_>>::new_uninit(flags)?; - b.write(x); - // SAFETY: We just wrote to it. - Ok(unsafe { b.assume_init() }) - } - - #[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) }) - } - - fn drop_contents(this: Self) -> Box<MaybeUninit<T>> { - let ptr = Box::into_raw(this); - // SAFETY: `ptr` is valid, because it came from `Box::into_raw`. - unsafe { ptr::drop_in_place(ptr) }; - - // CAST: `MaybeUninit<T>` is a transparent wrapper of `T`. - let ptr = ptr.cast::<MaybeUninit<T>>(); - - // SAFETY: `ptr` is valid for writes, because it came from `Box::into_raw` and it is valid for - // reads, since the pointer came from `Box::into_raw` and the type is `MaybeUninit<T>`. - unsafe { Box::from_raw(ptr) } - } -} --- a/rust/kernel/init.rs +++ b/rust/kernel/init.rs @@ -211,13 +211,12 @@ //! [`pin_init!`]: crate::pin_init!
use crate::{ - alloc::{box_ext::BoxExt, AllocError, Flags, KBox}, + alloc::{AllocError, Flags, KBox}, error::{self, Error}, sync::Arc, sync::UniqueArc, types::{Opaque, ScopeGuard}, }; -use alloc::boxed::Box; use core::{ cell::UnsafeCell, convert::Infallible, @@ -588,7 +587,6 @@ macro_rules! pin_init { /// # Examples /// /// ```rust -/// # #![feature(new_uninit)] /// use kernel::{init::{self, PinInit}, error::Error}; /// #[pin_data] /// struct BigBuf { @@ -1245,26 +1243,6 @@ impl<T> InPlaceInit<T> for Arc<T> { } }
-impl<T> InPlaceInit<T> for Box<T> { - type PinnedSelf = Pin<Self>; - - #[inline] - fn try_pin_init<E>(init: impl PinInit<T, E>, flags: Flags) -> Result<Self::PinnedSelf, E> - where - E: From<AllocError>, - { - <Box<_> as BoxExt<_>>::new_uninit(flags)?.write_pin_init(init) - } - - #[inline] - fn try_init<E>(init: impl Init<T, E>, flags: Flags) -> Result<Self, E> - where - E: From<AllocError>, - { - <Box<_> as BoxExt<_>>::new_uninit(flags)?.write_init(init) - } -} - impl<T> InPlaceInit<T> for UniqueArc<T> { type PinnedSelf = Pin<Self>;
@@ -1301,28 +1279,6 @@ pub trait InPlaceWrite<T> { fn write_pin_init<E>(self, init: impl PinInit<T, E>) -> Result<PinSelf::Initialized, E>; }
-impl<T> InPlaceWrite<T> for Box<MaybeUninit<T>> { - type Initialized = Box<T>; - - fn write_init<E>(mut self, init: impl Init<T, E>) -> Result<Self::Initialized, E> { - let slot = self.as_mut_ptr(); - // SAFETY: When init errors/panics, slot will get deallocated but not dropped, - // slot is valid. - unsafe { init.__init(slot)? }; - // SAFETY: All fields have been initialized. - Ok(unsafe { self.assume_init() }) - } - - fn write_pin_init<E>(mut self, init: impl PinInit<T, E>) -> Result<PinSelf::Initialized, E> { - let slot = self.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. - unsafe { init.__pinned_init(slot)? }; - // SAFETY: All fields have been initialized. - Ok(unsafe { self.assume_init() }.into()) - } -} - impl<T> InPlaceWrite<T> for UniqueArc<MaybeUninit<T>> { type Initialized = UniqueArc<T>;
--- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -16,7 +16,6 @@ #![feature(coerce_unsized)] #![feature(dispatch_from_dyn)] #![feature(lint_reasons)] -#![feature(new_uninit)] #![feature(unsize)]
// Ensure conditional compilation based on the kernel configuration works; --- a/rust/kernel/prelude.rs +++ b/rust/kernel/prelude.rs @@ -14,10 +14,10 @@ #[doc(no_inline)] pub use core::pin::Pin;
-pub use crate::alloc::{box_ext::BoxExt, flags::*, vec_ext::VecExt, KBox, KVBox, VBox}; +pub use crate::alloc::{flags::*, vec_ext::VecExt, KBox, KVBox, VBox};
#[doc(no_inline)] -pub use alloc::{boxed::Box, vec::Vec}; +pub use alloc::vec::Vec;
#[doc(no_inline)] pub use macros::{module, pin_data, pinned_drop, vtable, Zeroable}; --- a/rust/kernel/types.rs +++ b/rust/kernel/types.rs @@ -3,13 +3,11 @@ //! Kernel types.
use crate::init::{self, PinInit}; -use alloc::boxed::Box; use core::{ cell::UnsafeCell, marker::{PhantomData, PhantomPinned}, mem::{ManuallyDrop, MaybeUninit}, ops::{Deref, DerefMut}, - pin::Pin, ptr::NonNull, };
@@ -71,54 +69,6 @@ pub trait ForeignOwnable: Sized { } }
-impl<T: 'static> ForeignOwnable for Box<T> { - type Borrowed<'a> = &'a T; - - fn into_foreign(self) -> *const core::ffi::c_void { - Box::into_raw(self) as _ - } - - unsafe fn borrow<'a>(ptr: *const core::ffi::c_void) -> &'a T { - // SAFETY: The safety requirements for this function ensure that the object is still alive, - // so it is safe to dereference the raw pointer. - // The safety requirements of `from_foreign` also ensure that the object remains alive for - // the lifetime of the returned value. - unsafe { &*ptr.cast() } - } - - unsafe fn from_foreign(ptr: *const core::ffi::c_void) -> Self { - // SAFETY: The safety requirements of this function ensure that `ptr` comes from a previous - // call to `Self::into_foreign`. - unsafe { Box::from_raw(ptr as _) } - } -} - -impl<T: 'static> ForeignOwnable for Pin<Box<T>> { - type Borrowed<'a> = Pin<&'a T>; - - fn into_foreign(self) -> *const core::ffi::c_void { - // SAFETY: We are still treating the box as pinned. - Box::into_raw(unsafe { Pin::into_inner_unchecked(self) }) as _ - } - - unsafe fn borrow<'a>(ptr: *const core::ffi::c_void) -> Pin<&'a T> { - // SAFETY: The safety requirements for this function ensure that the object is still alive, - // so it is safe to dereference the raw pointer. - // The safety requirements of `from_foreign` also ensure that the object remains alive for - // the lifetime of the returned value. - let r = unsafe { &*ptr.cast() }; - - // SAFETY: This pointer originates from a `Pin<Box<T>>`. - unsafe { Pin::new_unchecked(r) } - } - - unsafe fn from_foreign(ptr: *const core::ffi::c_void) -> Self { - // SAFETY: The safety requirements of this function ensure that `ptr` comes from a previous - // call to `Self::into_foreign`. - unsafe { Pin::new_unchecked(Box::from_raw(ptr as _)) } - } -} - impl ForeignOwnable for () { type Borrowed<'a> = ();