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Allow to repurpose `?Sized` metadata

This commit is contained in:
Ruihan Li 2025-09-18 16:49:05 +08:00 committed by Tate, Hongliang Tian
parent 70b26f824d
commit c7429a7a5c
1 changed files with 10 additions and 10 deletions
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20
ostd/src/mm/frame/unique.rs
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@ -41,16 +41,6 @@ impl<M: AnyFrameMeta> UniqueFrame<M> {
})
}
/// Repurposes the frame with a new metadata.
pub fn repurpose<M1: AnyFrameMeta>(self, metadata: M1) -> UniqueFrame<M1> {
// SAFETY: We are the sole owner and the metadata is initialized.
unsafe { self.slot().drop_meta_in_place() };
// SAFETY: We are the sole owner.
unsafe { self.slot().write_meta(metadata) };
// SAFETY: The metadata is initialized with type `M1`.
unsafe { core::mem::transmute(self) }
}
/// Gets the metadata of this page.
pub fn meta(&self) -> &M {
// SAFETY: The type is tracked by the type system.
@ -94,6 +84,16 @@ impl<M: AnyFrameMeta + ?Sized> UniqueFrame<M> {
unsafe { &mut *self.slot().dyn_meta_ptr() }
}
/// Repurposes the frame with a new metadata.
pub fn repurpose<M1: AnyFrameMeta>(self, metadata: M1) -> UniqueFrame<M1> {
// SAFETY: We are the sole owner and the metadata is initialized.
unsafe { self.slot().drop_meta_in_place() };
// SAFETY: We are the sole owner.
unsafe { self.slot().write_meta(metadata) };
// SAFETY: The metadata is initialized with type `M1`.
unsafe { core::mem::transmute(self) }
}
/// Resets the frame to unused without up-calling the allocator.
///
/// This is solely useful for the allocator implementation/testing and