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authorWedson Almeida Filho <wedsonaf@gmail.com>2023-01-30 03:44:03 -0300
committerMiguel Ojeda <ojeda@kernel.org>2023-02-01 13:24:36 +0100
commit7118594466b8ed7285adb1dc177f2c84bfa33265 (patch)
treead1ec0e811e06a464b34be66a6873b91627d9486 /rust
parent26949bac1e8264c711a81f962845aa0538279c78 (diff)
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>
Diffstat (limited to 'rust')
-rw-r--r--rust/kernel/types.rs12
1 files changed, 12 insertions, 0 deletions
diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs
index 411655eca3e9..9d0fdbc55843 100644
--- a/rust/kernel/types.rs
+++ b/rust/kernel/types.rs
@@ -85,6 +85,18 @@ impl<T: 'static> ForeignOwnable for Box<T> {
}
}
+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.