[PATCH] rust: sync: fix safety comment for `static_lock_class`

[Benno Lossin <lossin@kernel.org>]

The safety comment mentions lockdep -- which from a Rust perspective
isn't important -- and doesn't mention the real reason for why it's
sound to create `LockClassKey` as uninitialized memory.

Signed-off-by: Benno Lossin <lossin@kernel.org>
---

I don't think we need to backport this.

---
 rust/kernel/sync.rs | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/rust/kernel/sync.rs b/rust/kernel/sync.rs
index 36a719015583..a10c812d8777 100644
--- a/rust/kernel/sync.rs
+++ b/rust/kernel/sync.rs
@@ -93,8 +93,11 @@ fn drop(self: Pin<&mut Self>) {
 macro_rules! static_lock_class {
     () => {{
         static CLASS: $crate::sync::LockClassKey =
-            // SAFETY: lockdep expects uninitialized memory when it's handed a statically allocated
-            // lock_class_key
+            // Lockdep expects uninitialized memory when it's handed a statically allocated `struct
+            // lock_class_key`.
+            //
+            // SAFETY: `LockClassKey` transparently wraps `Opaque` which permits uninitialized
+            // memory.
             unsafe { ::core::mem::MaybeUninit::uninit().assume_init() };
         $crate::prelude::Pin::static_ref(&CLASS)
     }};

base-commit: a5806cd506af5a7c19bcd596e4708b5c464bfd21
-- 
2.49.0