diff options
| -rw-r--r-- | rust/kernel/types.rs | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs index bd189d646adb..132ca1113083 100644 --- a/rust/kernel/types.rs +++ b/rust/kernel/types.rs @@ -9,6 +9,7 @@ use core::{ marker::{PhantomData, PhantomPinned}, mem::MaybeUninit, ops::{Deref, DerefMut}, + pin::Pin, ptr::NonNull, }; @@ -89,6 +90,32 @@ impl<T: 'static> ForeignOwnable for Box<T> { } } +impl<T: 'static> ForeignOwnable for Pin<Box<T>> { + type Borrowed<'a> = Pin<&'a T>; + + fn into_foreign(self) -> *const core::ffi::c_void { + // SAFETY: We are still treating the box as pinned. + Box::into_raw(unsafe { Pin::into_inner_unchecked(self) }) as _ + } + + unsafe fn borrow<'a>(ptr: *const core::ffi::c_void) -> Pin<&'a T> { + // SAFETY: The safety requirements for this function ensure that the object is still alive, + // so it is safe to dereference the raw pointer. + // The safety requirements of `from_foreign` also ensure that the object remains alive for + // the lifetime of the returned value. + let r = unsafe { &*ptr.cast() }; + + // SAFETY: This pointer originates from a `Pin<Box<T>>`. + unsafe { Pin::new_unchecked(r) } + } + + unsafe fn from_foreign(ptr: *const core::ffi::c_void) -> Self { + // SAFETY: The safety requirements of this function ensure that `ptr` comes from a previous + // call to `Self::into_foreign`. + unsafe { Pin::new_unchecked(Box::from_raw(ptr as _)) } + } +} + impl ForeignOwnable for () { type Borrowed<'a> = (); |