diff options
| author | Tamir Duberstein <tamird@gmail.com> | 2024-11-20 06:46:02 -0500 |
|---|---|---|
| committer | Miguel Ojeda <ojeda@kernel.org> | 2025-01-13 23:45:31 +0100 |
| commit | 5d385a356f628bd4a1d9f403588272d9626e3245 (patch) | |
| tree | 3453afc71e8769f7e26a9c078c97feb010eb39c1 /rust | |
| parent | aa991a2a819535a0014e1159b455b64e3db87510 (diff) | |
rust: arc: split unsafe block, add missing comment
The new SAFETY comment style is taken from existing comments in `deref`
and `drop.
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Link: https://lore.kernel.org/r/20241120-borrow-mut-v6-3-80dbadd00951@gmail.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Diffstat (limited to 'rust')
| -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) } |