rust: lockdep: Remove support for dynamically allocated LockClassKeys

unsafe impl Sync for LockClassKey {}

impl LockClassKey {

    /// Creates a new lock class key.

    pub const fn new() -> Self {

        Self(Opaque::uninit())

    }

    pub(crate) fn as_ptr(&self) -> *mut bindings::lock_class_key {

        self.0.get()

    }

}

impl Default for LockClassKey {

    fn default() -> Self {

        Self::new()

    }

}

/// Defines a new static lock class and returns a pointer to it.

#[doc(hidden)]

#[macro_export]

macro_rules! static_lock_class {

    () => {{

        static CLASS: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();

        static CLASS: $crate::sync::LockClassKey =

            // SAFETY: lockdep expects uninitialized memory when it's handed a statically allocated

            // lock_class_key

            unsafe { ::core::mem::MaybeUninit::uninit().assume_init() };

        &CLASS

    }};

}