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-rw-r--r--rust/kernel/alloc/kbox.rs8
-rw-r--r--rust/kernel/types.rs5
-rw-r--r--rust/pin-init/src/lib.rs8
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.
//