@@ -16,50 +16,55 @@
sync::atomic::{AtomicU64, Ordering},
};
-/// A wrapper around a blk-mq `struct request`. This represents an IO request.
+/// A wrapper around a blk-mq [`struct request`]. This represents an IO request.
///
/// # Implementation details
///
/// There are four states for a request that the Rust bindings care about:
///
-/// A) Request is owned by block layer (refcount 0)
-/// B) Request is owned by driver but with zero `ARef`s in existence
+/// 1. Request is owned by block layer (refcount 0)
+/// 2. Request is owned by driver but with zero [`ARef`]s in existence
/// (refcount 1)
-/// C) Request is owned by driver with exactly one `ARef` in existence
+/// 3. Request is owned by driver with exactly one [`ARef`] in existence
/// (refcount 2)
-/// D) Request is owned by driver with more than one `ARef` in existence
+/// 4. Request is owned by driver with more than one [`ARef`] in existence
/// (refcount > 2)
///
///
-/// We need to track A and B to ensure we fail tag to request conversions for
+/// We need to track 1 and 2 to ensure we fail tag to request conversions for
/// requests that are not owned by the driver.
///
-/// We need to track C and D to ensure that it is safe to end the request and hand
+/// We need to track 3 and 4 to ensure that it is safe to end the request and hand
/// back ownership to the block layer.
///
/// The states are tracked through the private `refcount` field of
/// `RequestDataWrapper`. This structure lives in the private data area of the C
-/// `struct request`.
+/// [`struct request`].
///
/// # Invariants
///
-/// * `self.0` is a valid `struct request` created by the C portion of the kernel.
+/// * `self.0` is a valid [`struct request`] created by the C portion of the
+/// kernel.
/// * The private data area associated with this request must be an initialized
/// and valid `RequestDataWrapper<T>`.
/// * `self` is reference counted by atomic modification of
-/// self.wrapper_ref().refcount().
+/// `self.wrapper_ref().refcount()`.
+///
+/// [`struct request`]: srctree/include/linux/blk-mq.h
///
#[repr(transparent)]
pub struct Request<T: Operations>(Opaque<bindings::request>, PhantomData<T>);
impl<T: Operations> Request<T> {
- /// Create an `ARef<Request>` from a `struct request` pointer.
+ /// Create an [`ARef<Request>`] from a [`struct request`] pointer.
///
/// # Safety
///
/// * The caller must own a refcount on `ptr` that is transferred to the
- /// returned `ARef`.
- /// * The type invariants for `Request` must hold for the pointee of `ptr`.
+ /// returned [`ARef`].
+ /// * The type invariants for [`Request`] must hold for the pointee of `ptr`.
+ ///
+ /// [`struct request`]: srctree/include/linux/blk-mq.h
pub(crate) unsafe fn aref_from_raw(ptr: *mut bindings::request) -> ARef<Self> {
// INVARIANT: By the safety requirements of this function, invariants are upheld.
// SAFETY: By the safety requirement of this function, we own a
@@ -84,12 +89,14 @@ pub(crate) unsafe fn start_unchecked(this: &ARef<Self>) {
}
/// Try to take exclusive ownership of `this` by dropping the refcount to 0.
- /// This fails if `this` is not the only `ARef` pointing to the underlying
- /// `Request`.
+ /// This fails if `this` is not the only [`ARef`] pointing to the underlying
+ /// [`Request`].
///
- /// If the operation is successful, `Ok` is returned with a pointer to the
- /// C `struct request`. If the operation fails, `this` is returned in the
- /// `Err` variant.
+ /// If the operation is successful, [`Ok`] is returned with a pointer to the
+ /// C [`struct request`]. If the operation fails, `this` is returned in the
+ /// [`Err`] variant.
+ ///
+ /// [`struct request`]: srctree/include/linux/blk-mq.h
fn try_set_end(this: ARef<Self>) -> Result<*mut bindings::request, ARef<Self>> {
// We can race with `TagSet::tag_to_rq`
if let Err(_old) = this.wrapper_ref().refcount().compare_exchange(
@@ -109,7 +116,7 @@ fn try_set_end(this: ARef<Self>) -> Result<*mut bindings::request, ARef<Self>> {
/// Notify the block layer that the request has been completed without errors.
///
- /// This function will return `Err` if `this` is not the only `ARef`
+ /// This function will return [`Err`] if `this` is not the only [`ARef`]
/// referencing the request.
pub fn end_ok(this: ARef<Self>) -> Result<(), ARef<Self>> {
let request_ptr = Self::try_set_end(this)?;
@@ -123,13 +130,13 @@ pub fn end_ok(this: ARef<Self>) -> Result<(), ARef<Self>> {
Ok(())
}
- /// Return a pointer to the `RequestDataWrapper` stored in the private area
+ /// Return a pointer to the [`RequestDataWrapper`] stored in the private area
/// of the request structure.
///
/// # Safety
///
/// - `this` must point to a valid allocation of size at least size of
- /// `Self` plus size of `RequestDataWrapper`.
+ /// [`Self`] plus size of [`RequestDataWrapper`].
pub(crate) unsafe fn wrapper_ptr(this: *mut Self) -> NonNull<RequestDataWrapper> {
let request_ptr = this.cast::<bindings::request>();
// SAFETY: By safety requirements for this function, `this` is a
@@ -141,7 +148,7 @@ pub(crate) unsafe fn wrapper_ptr(this: *mut Self) -> NonNull<RequestDataWrapper>
unsafe { NonNull::new_unchecked(wrapper_ptr) }
}
- /// Return a reference to the `RequestDataWrapper` stored in the private
+ /// Return a reference to the [`RequestDataWrapper`] stored in the private
/// area of the request structure.
pub(crate) fn wrapper_ref(&self) -> &RequestDataWrapper {
// SAFETY: By type invariant, `self.0` is a valid allocation. Further,
@@ -152,13 +159,15 @@ pub(crate) fn wrapper_ref(&self) -> &RequestDataWrapper {
}
}
-/// A wrapper around data stored in the private area of the C `struct request`.
+/// A wrapper around data stored in the private area of the C [`struct request`].
+///
+/// [`struct request`]: srctree/include/linux/blk-mq.h
pub(crate) struct RequestDataWrapper {
/// The Rust request refcount has the following states:
///
/// - 0: The request is owned by C block layer.
- /// - 1: The request is owned by Rust abstractions but there are no ARef references to it.
- /// - 2+: There are `ARef` references to the request.
+ /// - 1: The request is owned by Rust abstractions but there are no [`ARef`] references to it.
+ /// - 2+: There are [`ARef`] references to the request.
refcount: AtomicU64,
}
@@ -204,7 +213,7 @@ fn atomic_relaxed_op_return(target: &AtomicU64, op: impl Fn(u64) -> u64) -> u64
}
/// Store the result of `op(target.load)` in `target` if `target.load() !=
-/// pred`, returning true if the target was updated.
+/// pred`, returning `true` if the target was updated.
fn atomic_relaxed_op_unless(target: &AtomicU64, op: impl Fn(u64) -> u64, pred: u64) -> bool {
target
.fetch_update(Ordering::Relaxed, Ordering::Relaxed, |x| {
Fix several issues with rustdoc formatting for the `kernel::block::mq::Request` module, in particular: - An ordered list not rendering correctly, fixed by using numbers prefixes instead of letters - Code snippets formatted as regular text, fixed by wrapping the code with `back-ticks` - References to types missing intra-doc links, fixed by wrapping the types with [square brackets] Reported-by: Miguel Ojeda <ojeda@kernel.org> Closes: https://github.com/Rust-for-Linux/linux/issues/1108 Signed-off-by: Francesco Zardi <frazar00@gmail.com> --- V1->V2: Fixed the order of the "Reported-by", "Closes", and "Signed-off-by" tags. Removed empty line after "Closes: ". Many thanks to Miguel for the prompt feedback! rust/kernel/block/mq/request.rs | 61 +++++++++++++++++++-------------- 1 file changed, 35 insertions(+), 26 deletions(-) base-commit: a335e95914046c6bed45c0d17cabcd483682cf5e