Commit 71185944 authored Jan 30, 2023 by Wedson Almeida Filho Committed by Miguel Ojeda Feb 01, 2023

rust: types: implement `ForeignOwnable` for the unit type



This allows us to use the unit type `()` when we have no object whose
ownership must be managed but one implementing the `ForeignOwnable`
trait is needed.

Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

parent 26949bac

rust/kernel/types.rs

+12 −0

Original line number	Diff line number	Diff line
		@@ -85,6 +85,18 @@ unsafe fn from_foreign(ptr: *const core::ffi::c_void) -> Self {
		}
		}

		impl ForeignOwnable for () {
		type Borrowed<'a> = ();

		fn into_foreign(self) -> *const core::ffi::c_void {
		core::ptr::NonNull::dangling().as_ptr()
		}

		unsafe fn borrow<'a>(_: *const core::ffi::c_void) -> Self::Borrowed<'a> {}

		unsafe fn from_foreign(_: *const core::ffi::c_void) -> Self {}
		}

		/// Runs a cleanup function/closure when dropped.
		///
		/// The [`ScopeGuard::dismiss`] function prevents the cleanup function from running.