diff options
-rw-r--r-- | rust/kernel/alloc/kbox.rs | 8 | ||||
-rw-r--r-- | rust/kernel/types.rs | 5 | ||||
-rw-r--r-- | rust/pin-init/src/lib.rs | 8 |
3 files changed, 12 insertions, 9 deletions
diff --git a/rust/kernel/alloc/kbox.rs b/rust/kernel/alloc/kbox.rs index 39a3ea7542da..9861433559dc 100644 --- a/rust/kernel/alloc/kbox.rs +++ b/rust/kernel/alloc/kbox.rs @@ -15,7 +15,7 @@ use core::pin::Pin; use core::ptr::NonNull; use core::result::Result; -use crate::init::{InPlaceWrite, Init, PinInit}; +use crate::init::{InPlaceWrite, Init, PinInit, Zeroable}; use crate::init_ext::InPlaceInit; use crate::types::ForeignOwnable; @@ -100,6 +100,12 @@ pub type VBox<T> = Box<T, super::allocator::Vmalloc>; /// ``` pub type KVBox<T> = Box<T, super::allocator::KVmalloc>; +// SAFETY: All zeros is equivalent to `None` (option layout optimization guarantee). +// +// In this case we are allowed to use `T: ?Sized`, since all zeros is the `None` variant and there +// is no problem with a VTABLE pointer being null. +unsafe impl<T: ?Sized, A: Allocator> Zeroable for Option<Box<T, A>> {} + // SAFETY: `Box` is `Send` if `T` is `Send` because the `Box` owns a `T`. unsafe impl<T, A> Send for Box<T, A> where diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs index 5801eeb69dc5..7237b2224680 100644 --- a/rust/kernel/types.rs +++ b/rust/kernel/types.rs @@ -2,7 +2,7 @@ //! Kernel types. -use crate::init::{self, PinInit}; +use crate::init::{self, PinInit, Zeroable}; use core::{ cell::UnsafeCell, marker::{PhantomData, PhantomPinned}, @@ -309,6 +309,9 @@ pub struct Opaque<T> { _pin: PhantomPinned, } +// SAFETY: `Opaque<T>` allows the inner value to be any bit pattern, including all zeros. +unsafe impl<T> Zeroable for Opaque<T> {} + impl<T> Opaque<T> { /// Creates a new opaque value. pub const fn new(value: T) -> Self { diff --git a/rust/pin-init/src/lib.rs b/rust/pin-init/src/lib.rs index f88465e0bb76..aad6486d33fc 100644 --- a/rust/pin-init/src/lib.rs +++ b/rust/pin-init/src/lib.rs @@ -211,10 +211,7 @@ //! [`pin_data`]: ::macros::pin_data //! [`pin_init!`]: crate::pin_init! -use crate::{ - alloc::KBox, - types::{Opaque, ScopeGuard}, -}; +use crate::{alloc::KBox, types::ScopeGuard}; use core::{ cell::UnsafeCell, convert::Infallible, @@ -1342,8 +1339,6 @@ impl_zeroable! { // SAFETY: Type is allowed to take any value, including all zeros. {<T>} MaybeUninit<T>, - // SAFETY: Type is allowed to take any value, including all zeros. - {<T>} Opaque<T>, // SAFETY: `T: Zeroable` and `UnsafeCell` is `repr(transparent)`. {<T: ?Sized + Zeroable>} UnsafeCell<T>, @@ -1358,7 +1353,6 @@ impl_zeroable! { // // In this case we are allowed to use `T: ?Sized`, since all zeros is the `None` variant. {<T: ?Sized>} Option<NonNull<T>>, - {<T: ?Sized>} Option<KBox<T>>, // SAFETY: `null` pointer is valid. // |