1 files changed, 41 insertions, 6 deletions

diff --git a/rust/kernel/workqueue.rs b/rust/kernel/workqueue.rs
index 4d1d2062f6eb..f98bd02b838f 100644
--- a/rust/kernel/workqueue.rs
+++ b/rust/kernel/workqueue.rs
@@ -60,7 +60,7 @@
 //!     type Pointer = Arc<MyStruct>;
 //!
 //!     fn run(this: Arc<MyStruct>) {
-//!         pr_info!("The value is: {}", this.value);
+//!         pr_info!("The value is: {}\n", this.value);
 //!     }
 //! }
 //!
@@ -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:
@@ -107,7 +108,7 @@
 //!     type Pointer = Arc<MyStruct>;
 //!
 //!     fn run(this: Arc<MyStruct>) {
-//!         pr_info!("The value is: {}", this.value_1);
+//!         pr_info!("The value is: {}\n", this.value_1);
 //!     }
 //! }
 //!
@@ -115,7 +116,7 @@
 //!     type Pointer = Arc<MyStruct>;
 //!
 //!     fn run(this: Arc<MyStruct>) {
-//!         pr_info!("The second value is: {}", this.value_2);
+//!         pr_info!("The second value is: {}\n", this.value_2);
 //!     }
 //! }
 //!
@@ -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)
@@ -366,7 +369,7 @@ unsafe impl<T: ?Sized, const ID: u64> Sync for Work<T, ID> {}
 impl<T: ?Sized, const ID: u64> Work<T, ID> {
     /// Creates a new instance of [`Work`].
     #[inline]
-    pub fn new(name: &'static CStr, key: &'static LockClassKey) -> impl PinInit<Self>
+    pub fn new(name: &'static CStr, key: Pin<&'static LockClassKey>) -> impl PinInit<Self>
     where
         T: WorkItem<ID>,
     {
@@ -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>,
@@ -686,3 +703,21 @@ pub fn system_freezable_power_efficient() -> &'static Queue {
     // SAFETY: `system_freezable_power_efficient_wq` is a C global, always available.
     unsafe { Queue::from_raw(bindings::system_freezable_power_efficient_wq) }
 }
+
+/// Returns the system bottom halves work queue (`system_bh_wq`).
+///
+/// It is similar to the one returned by [`system`] but for work items which
+/// need to run from a softirq context.
+pub fn system_bh() -> &'static Queue {
+    // SAFETY: `system_bh_wq` is a C global, always available.
+    unsafe { Queue::from_raw(bindings::system_bh_wq) }
+}
+
+/// Returns the system bottom halves high-priority work queue (`system_bh_highpri_wq`).
+///
+/// It is similar to the one returned by [`system_bh`] but for work items which
+/// require higher scheduling priority.
+pub fn system_bh_highpri() -> &'static Queue {
+    // SAFETY: `system_bh_highpri_wq` is a C global, always available.
+    unsafe { Queue::from_raw(bindings::system_bh_highpri_wq) }
+}