diff --git a/rust/kernel/init.rs b/rust/kernel/init.rs index 771701805a97..a8068f99fcaa 100644 --- a/rust/kernel/init.rs +++ b/rust/kernel/init.rs @@ -1183,13 +1183,7 @@ impl InPlaceInit for Box { where E: From, { - let mut this = 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. - unsafe { init.__pinned_init(slot)? }; - // SAFETY: All fields have been initialized. - Ok(unsafe { this.assume_init() }.into()) + as BoxExt<_>>::new_uninit(flags)?.write_pin_init(init) } #[inline] @@ -1197,13 +1191,7 @@ impl InPlaceInit for Box { where E: From, { - let mut this = 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. - unsafe { init.__init(slot)? }; - // SAFETY: All fields have been initialized. - Ok(unsafe { this.assume_init() }) + as BoxExt<_>>::new_uninit(flags)?.write_init(init) } } @@ -1215,13 +1203,7 @@ impl InPlaceInit for UniqueArc { where E: From, { - 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. - unsafe { init.__pinned_init(slot)? }; - // SAFETY: All fields have been initialized. - Ok(unsafe { this.assume_init() }.into()) + UniqueArc::new_uninit(flags)?.write_pin_init(init) } #[inline] @@ -1229,13 +1211,67 @@ impl InPlaceInit for UniqueArc { where E: From, { - let mut this = UniqueArc::new_uninit(flags)?; - let slot = this.as_mut_ptr(); + UniqueArc::new_uninit(flags)?.write_init(init) + } +} + +/// Smart pointer containing uninitialized memory and that can write a value. +pub trait InPlaceWrite { + /// The type `Self` turns into when the contents are initialized. + type Initialized; + + /// Use the given initializer to write a value into `self`. + /// + /// Does not drop the current value and considers it as uninitialized memory. + fn write_init(self, init: impl Init) -> Result; + + /// Use the given pin-initializer to write a value into `self`. + /// + /// Does not drop the current value and considers it as uninitialized memory. + fn write_pin_init(self, init: impl PinInit) -> Result, E>; +} + +impl InPlaceWrite for Box> { + type Initialized = Box; + + fn write_init(mut self, init: impl Init) -> Result { + 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 { this.assume_init() }) + Ok(unsafe { self.assume_init() }) + } + + fn write_pin_init(mut self, init: impl PinInit) -> Result, 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 InPlaceWrite for UniqueArc> { + type Initialized = UniqueArc; + + fn write_init(mut self, init: impl Init) -> Result { + 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(mut self, init: impl PinInit) -> Result, 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()) } } diff --git a/rust/kernel/prelude.rs b/rust/kernel/prelude.rs index b37a0b3180fb..4571daec0961 100644 --- a/rust/kernel/prelude.rs +++ b/rust/kernel/prelude.rs @@ -37,6 +37,6 @@ pub use super::error::{code::*, Error, Result}; pub use super::{str::CStr, ThisModule}; -pub use super::init::{InPlaceInit, Init, PinInit}; +pub use super::init::{InPlaceInit, InPlaceWrite, Init, PinInit}; pub use super::current;