diff options
Diffstat (limited to 'rust/kernel')
| -rw-r--r-- | rust/kernel/init.rs | 128 | ||||
| -rw-r--r-- | rust/kernel/sync/arc.rs | 24 |
2 files changed, 139 insertions, 13 deletions
diff --git a/rust/kernel/init.rs b/rust/kernel/init.rs index ecef0376d726..6499cf5c9c20 100644 --- a/rust/kernel/init.rs +++ b/rust/kernel/init.rs @@ -114,10 +114,16 @@ //! [`impl Init<T, E>`]: Init //! [`Opaque`]: kernel::types::Opaque //! [`pin_data`]: ::macros::pin_data -//! [`UniqueArc<T>`]: kernel::sync::UniqueArc +use crate::{ + error::{self, Error}, + sync::UniqueArc, +}; use alloc::boxed::Box; -use core::{cell::Cell, convert::Infallible, marker::PhantomData, mem::MaybeUninit, ptr}; +use core::{ + alloc::AllocError, cell::Cell, convert::Infallible, marker::PhantomData, mem::MaybeUninit, + pin::Pin, ptr, +}; #[doc(hidden)] pub mod __internal; @@ -309,7 +315,6 @@ pub mod macros; /// /// [`try_pin_init!`]: kernel::try_pin_init /// [`NonNull<Self>`]: core::ptr::NonNull -/// [`Error`]: kernel::error::Error // For a detailed example of how this macro works, see the module documentation of the hidden // module `__internal` inside of `init/__internal.rs`. #[macro_export] @@ -363,8 +368,6 @@ macro_rules! pin_init { /// } /// } /// ``` -/// -/// [`Error`]: kernel::error::Error // For a detailed example of how this macro works, see the module documentation of the hidden // module `__internal` inside of `init/__internal.rs`. #[macro_export] @@ -586,8 +589,6 @@ macro_rules! try_pin_init { /// /// This initializer is for initializing data in-place that might later be moved. If you want to /// pin-initialize, use [`pin_init!`]. -/// -/// [`Error`]: kernel::error::Error // For a detailed example of how this macro works, see the module documentation of the hidden // module `__internal` inside of `init/__internal.rs`. #[macro_export] @@ -635,8 +636,6 @@ macro_rules! init { /// } /// } /// ``` -/// -/// [`Error`]: kernel::error::Error // For a detailed example of how this macro works, see the module documentation of the hidden // module `__internal` inside of `init/__internal.rs`. #[macro_export] @@ -842,7 +841,8 @@ macro_rules! try_init { /// A pin-initializer for the type `T`. /// /// To use this initializer, you will need a suitable memory location that can hold a `T`. This can -/// be [`Box<T>`], [`Arc<T>`], [`UniqueArc<T>`]. +/// be [`Box<T>`], [`Arc<T>`], [`UniqueArc<T>`]. Use the [`InPlaceInit::pin_init`] function of a +/// smart pointer like [`Arc<T>`] on this. /// /// Also see the [module description](self). /// @@ -861,7 +861,6 @@ macro_rules! try_init { /// /// [`Arc<T>`]: crate::sync::Arc /// [`Arc::pin_init`]: crate::sync::Arc::pin_init -/// [`UniqueArc<T>`]: kernel::sync::UniqueArc #[must_use = "An initializer must be used in order to create its value."] pub unsafe trait PinInit<T: ?Sized, E = Infallible>: Sized { /// Initializes `slot`. @@ -878,7 +877,8 @@ pub unsafe trait PinInit<T: ?Sized, E = Infallible>: Sized { /// An initializer for `T`. /// /// To use this initializer, you will need a suitable memory location that can hold a `T`. This can -/// be [`Box<T>`], [`Arc<T>`], [`UniqueArc<T>`]. Because [`PinInit<T, E>`] is a super trait, you can +/// be [`Box<T>`], [`Arc<T>`], [`UniqueArc<T>`]. Use the [`InPlaceInit::init`] function of a smart +/// pointer like [`Arc<T>`] on this. Because [`PinInit<T, E>`] is a super trait, you can /// use every function that takes it as well. /// /// Also see the [module description](self). @@ -903,7 +903,6 @@ pub unsafe trait PinInit<T: ?Sized, E = Infallible>: Sized { /// move the pointee after initialization. /// /// [`Arc<T>`]: crate::sync::Arc -/// [`UniqueArc<T>`]: kernel::sync::UniqueArc #[must_use = "An initializer must be used in order to create its value."] pub unsafe trait Init<T: ?Sized, E = Infallible>: Sized { /// Initializes `slot`. @@ -982,3 +981,106 @@ unsafe impl<T> Init<T> for T { Ok(()) } } + +/// Smart pointer that can initialize memory in-place. +pub trait InPlaceInit<T>: Sized { + /// Use the given pin-initializer to pin-initialize a `T` inside of a new smart pointer of this + /// 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> + where + E: From<AllocError>; + + /// Use the given pin-initializer to pin-initialize a `T` inside of a new smart pointer of this + /// 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>> + where + Error: From<E>, + { + // SAFETY: We delegate to `init` and only change the error type. + let init = unsafe { + pin_init_from_closure(|slot| init.__pinned_init(slot).map_err(|e| Error::from(e))) + }; + Self::try_pin_init(init) + } + + /// Use the given initializer to in-place initialize a `T`. + fn try_init<E>(init: impl Init<T, E>) -> 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> + where + Error: From<E>, + { + // SAFETY: We delegate to `init` and only change the error type. + let init = unsafe { + init_from_closure(|slot| init.__pinned_init(slot).map_err(|e| Error::from(e))) + }; + Self::try_init(init) + } +} + +impl<T> InPlaceInit<T> for Box<T> { + #[inline] + fn try_pin_init<E>(init: impl PinInit<T, E>) -> Result<Pin<Self>, E> + where + E: From<AllocError>, + { + let mut this = Box::try_new_uninit()?; + 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. + unsafe { init.__pinned_init(slot)? }; + // SAFETY: All fields have been initialized. + Ok(unsafe { this.assume_init() }.into()) + } + + #[inline] + fn try_init<E>(init: impl Init<T, E>) -> Result<Self, E> + where + E: From<AllocError>, + { + let mut this = Box::try_new_uninit()?; + let slot = this.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 { this.assume_init() }) + } +} + +impl<T> InPlaceInit<T> for UniqueArc<T> { + #[inline] + fn try_pin_init<E>(init: impl PinInit<T, E>) -> Result<Pin<Self>, E> + where + E: From<AllocError>, + { + let mut this = UniqueArc::try_new_uninit()?; + 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. + unsafe { init.__pinned_init(slot)? }; + // SAFETY: All fields have been initialized. + Ok(unsafe { this.assume_init() }.into()) + } + + #[inline] + fn try_init<E>(init: impl Init<T, E>) -> Result<Self, E> + where + E: From<AllocError>, + { + let mut this = UniqueArc::try_new_uninit()?; + let slot = this.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 { this.assume_init() }) + } +} diff --git a/rust/kernel/sync/arc.rs b/rust/kernel/sync/arc.rs index 34d0e7cbe62e..b45769a29541 100644 --- a/rust/kernel/sync/arc.rs +++ b/rust/kernel/sync/arc.rs @@ -17,6 +17,8 @@ use crate::{ bindings, + error::{self, Error}, + init::{InPlaceInit, Init, PinInit}, types::{ForeignOwnable, Opaque}, }; use alloc::boxed::Box; @@ -166,6 +168,28 @@ impl<T> Arc<T> { // `Arc` object. Ok(unsafe { Self::from_inner(Box::leak(inner).into()) }) } + + /// Use the given initializer to in-place initialize a `T`. + /// + /// If `T: !Unpin` it will not be able to move afterwards. + #[inline] + pub fn pin_init<E>(init: impl PinInit<T, E>) -> error::Result<Self> + where + Error: From<E>, + { + UniqueArc::pin_init(init).map(|u| u.into()) + } + + /// Use the given initializer to in-place initialize a `T`. + /// + /// This is equivalent to [`pin_init`], since an [`Arc`] is always pinned. + #[inline] + pub fn init<E>(init: impl Init<T, E>) -> error::Result<Self> + where + Error: From<E>, + { + UniqueArc::init(init).map(|u| u.into()) + } } impl<T: ?Sized> Arc<T> { |