Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
rust: block: add remote completion to `Request`
Allow users of rust block device driver API to schedule completion of
requests via `blk_mq_complete_request_remote`.
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
Link: https://lore.kernel.org/r/20250902-rnull-up-v6-16-v7-16-b5212cc89b98@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
authored by
Andreas Hindborg
and committed by
Jens Axboe
4ec05284
bde50e28
+47
-4
+9
drivers/block/rnull/rnull.rs
+9
drivers/block/rnull/rnull.rs
···
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}
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fn commit_rqs(_queue_data: ()) {}
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+
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fn complete(rq: ARef<mq::Request<Self>>) {
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mq::Request::end_ok(rq)
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.map_err(|_e| kernel::error::code::EIO)
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// We take no refcounts on the request, so we expect to be able to
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// end the request. The request reference must be unique at this
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// point, and so `end_ok` cannot fail.
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.expect("Fatal error - expected to be able to end request");
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}
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}
+6
rust/kernel/block/mq.rs
+6
rust/kernel/block/mq.rs
···
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//! }
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//!
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//! fn commit_rqs(_queue_data: ()) {}
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//!
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//! fn complete(rq: ARef<Request<Self>>) {
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//! Request::end_ok(rq)
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//! .map_err(|_e| kernel::error::code::EIO)
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//! .expect("Fatal error - expected to be able to end request");
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//! }
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//! }
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//!
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//! let tagset: Arc<TagSet<MyBlkDevice>> =
+15
-4
rust/kernel/block/mq/operations.rs
+15
-4
rust/kernel/block/mq/operations.rs
···
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/// Called by the kernel to indicate that queued requests should be submitted.
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fn commit_rqs(queue_data: ForeignBorrowed<'_, Self::QueueData>);
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/// Called by the kernel when the request is completed.
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fn complete(rq: ARef<Request<Self>>);
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/// Called by the kernel to poll the device for completed requests. Only
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/// used for poll queues.
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fn poll() -> bool {
···
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T::commit_rqs(queue_data)
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}
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-
/// This function is called by the C kernel. It is not currently
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/// implemented, and there is no way to exercise this code path.
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/// This function is called by the C kernel. A pointer to this function is
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/// installed in the `blk_mq_ops` vtable for the driver.
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///
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/// # Safety
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///
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/// This function may only be called by blk-mq C infrastructure.
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unsafe extern "C" fn complete_callback(_rq: *mut bindings::request) {}
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/// This function may only be called by blk-mq C infrastructure. `rq` must
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/// point to a valid request that has been marked as completed. The pointee
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/// of `rq` must be valid for write for the duration of this function.
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unsafe extern "C" fn complete_callback(rq: *mut bindings::request) {
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// SAFETY: This function can only be dispatched through
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// `Request::complete`. We leaked a refcount then which we pick back up
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// now.
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let aref = unsafe { Request::aref_from_raw(rq) };
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T::complete(aref);
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}
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/// This function is called by the C kernel. A pointer to this function is
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/// installed in the `blk_mq_ops` vtable for the driver.
+17
rust/kernel/block/mq/request.rs
+17
rust/kernel/block/mq/request.rs
···
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Ok(())
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}
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/// Complete the request by scheduling `Operations::complete` for
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/// execution.
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///
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/// The function may be scheduled locally, via SoftIRQ or remotely via IPMI.
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/// See `blk_mq_complete_request_remote` in [`blk-mq.c`] for details.
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///
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/// [`blk-mq.c`]: srctree/block/blk-mq.c
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pub fn complete(this: ARef<Self>) {
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let ptr = ARef::into_raw(this).cast::<bindings::request>().as_ptr();
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// SAFETY: By type invariant, `self.0` is a valid `struct request`
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if !unsafe { bindings::blk_mq_complete_request_remote(ptr) } {
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// SAFETY: We released a refcount above that we can reclaim here.
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let this = unsafe { Request::aref_from_raw(ptr) };
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T::complete(this);
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}
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}
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/// Return a pointer to the [`RequestDataWrapper`] stored in the private area
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/// of the request structure.
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///