diff options
| -rw-r--r-- | rust/kernel/sync/arc.rs | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/rust/kernel/sync/arc.rs b/rust/kernel/sync/arc.rs index 378925e553ec..93eac650146a 100644 --- a/rust/kernel/sync/arc.rs +++ b/rust/kernel/sync/arc.rs @@ -389,10 +389,14 @@ impl<T: ?Sized> AsRef<T> for Arc<T> { impl<T: ?Sized> Clone for Arc<T> { fn clone(&self) -> Self { + // SAFETY: By the type invariant, there is necessarily a reference to the object, so it is + // safe to dereference it. + let refcount = unsafe { self.ptr.as_ref() }.refcount.get(); + // INVARIANT: C `refcount_inc` saturates the refcount, so it cannot overflow to zero. // SAFETY: By the type invariant, there is necessarily a reference to the object, so it is // safe to increment the refcount. - unsafe { bindings::refcount_inc(self.ptr.as_ref().refcount.get()) }; + unsafe { bindings::refcount_inc(refcount) }; // SAFETY: We just incremented the refcount. This increment is now owned by the new `Arc`. unsafe { Self::from_inner(self.ptr) } |