diff options
Diffstat (limited to 'rust/kernel/workqueue.rs')
| -rw-r--r-- | rust/kernel/workqueue.rs | 21 | 
1 files changed, 19 insertions, 2 deletions
| diff --git a/rust/kernel/workqueue.rs b/rust/kernel/workqueue.rs index 4d1d2062f6eb..0cd100d2aefb 100644 --- a/rust/kernel/workqueue.rs +++ b/rust/kernel/workqueue.rs @@ -69,6 +69,7 @@  //! fn print_later(val: Arc<MyStruct>) {  //!     let _ = workqueue::system().enqueue(val);  //! } +//! # print_later(MyStruct::new(42).unwrap());  //! ```  //!  //! The following example shows how multiple `work_struct` fields can be used: @@ -126,6 +127,8 @@  //! fn print_2_later(val: Arc<MyStruct>) {  //!     let _ = workqueue::system().enqueue::<Arc<MyStruct>, 2>(val);  //! } +//! # print_1_later(MyStruct::new(24, 25).unwrap()); +//! # print_2_later(MyStruct::new(41, 42).unwrap());  //! ```  //!  //! C header: [`include/linux/workqueue.h`](srctree/include/linux/workqueue.h) @@ -519,7 +522,15 @@ impl_has_work! {      impl{T} HasWork<Self> for ClosureWork<T> { self.work }  } -// SAFETY: TODO. +// SAFETY: The `__enqueue` implementation in RawWorkItem uses a `work_struct` initialized with the +// `run` method of this trait as the function pointer because: +//   - `__enqueue` gets the `work_struct` from the `Work` field, using `T::raw_get_work`. +//   - The only safe way to create a `Work` object is through `Work::new`. +//   - `Work::new` makes sure that `T::Pointer::run` is passed to `init_work_with_key`. +//   - Finally `Work` and `RawWorkItem` guarantee that the correct `Work` field +//     will be used because of the ID const generic bound. This makes sure that `T::raw_get_work` +//     uses the correct offset for the `Work` field, and `Work::new` picks the correct +//     implementation of `WorkItemPointer` for `Arc<T>`.  unsafe impl<T, const ID: u64> WorkItemPointer<ID> for Arc<T>  where      T: WorkItem<ID, Pointer = Self>, @@ -537,7 +548,13 @@ where      }  } -// SAFETY: TODO. +// SAFETY: The `work_struct` raw pointer is guaranteed to be valid for the duration of the call to +// the closure because we get it from an `Arc`, which means that the ref count will be at least 1, +// and we don't drop the `Arc` ourselves. If `queue_work_on` returns true, it is further guaranteed +// to be valid until a call to the function pointer in `work_struct` because we leak the memory it +// points to, and only reclaim it if the closure returns false, or in `WorkItemPointer::run`, which +// is what the function pointer in the `work_struct` must be pointing to, according to the safety +// requirements of `WorkItemPointer`.  unsafe impl<T, const ID: u64> RawWorkItem<ID> for Arc<T>  where      T: WorkItem<ID, Pointer = Self>, | 
