Commit a4c9f71e authored by Danilo Krummrich's avatar Danilo Krummrich
Browse files

rust: device: implement Device::parent() 



Device::parent() returns a reference to the device' parent device, if
any.

Reviewed-by: default avatarAlice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20250414131934.28418-3-dakr@kernel.org


Signed-off-by: default avatarDanilo Krummrich <dakr@kernel.org>
parent 9647b6c5

rust/kernel/device.rs

+19 −0
Original line number Diff line number Diff line
@@ -67,6 +67,25 @@ pub(crate) fn as_raw(&self) -> *mut bindings::device { 
        self.0.get()

    }



    /// Returns a reference to the parent device, if any.

    #[expect(unused)]

    pub(crate) fn parent(&self) -> Option<&Self> {

        // SAFETY:

        // - By the type invariant `self.as_raw()` is always valid.

        // - The parent device is only ever set at device creation.

        let parent = unsafe { (*self.as_raw()).parent };



        if parent.is_null() {

            None

        } else {

            // SAFETY:

            // - Since `parent` is not NULL, it must be a valid pointer to a `struct device`.

            // - `parent` is valid for the lifetime of `self`, since a `struct device` holds a

            //   reference count of its parent.

            Some(unsafe { Self::as_ref(parent) })

        }

    }



    /// Convert a raw C `struct device` pointer to a `&'a Device`.

    ///

    /// # Safety