From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2D8F53093A6; Fri, 22 Aug 2025 12:16:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755864983; cv=none; b=Z638fDK+xfOR7LLB26qjXHNmkGPtTVmQU1A/ZuqJq5KYQ0gp44mQlRlrCXhgnDFbMP0c1d1/4dvWMEFyLjyTogObR954d/OnODMoWS9QgHk0lVuTbsfv5mbDn49hbX67nlQHkuILgvDnzc1JP4wk6TxB3jfnS0G078qiyljZNhA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755864983; c=relaxed/simple; bh=/q3BHJ4OBUGrEvfMJAnS4b16x6NbLDJGWQVOq+Cb5uU=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=LdUgJ8zCY5qamZySCrJ2IjftmMf9OIdmhn5X4N4DJLzEsJAntEChGSWKzXNOTlZKl1pVVRp7xb5EboBNRtZ3Ioa0QfTTDtSIjh6bJCZdJM+6vQ53DO48bJUmlc8ILk5OsWmci3EizgfEL6ZtZzJwXEJwuk4B1M0hd/GZv4w2hFU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RtMtEpoY; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RtMtEpoY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 31164C116C6; Fri, 22 Aug 2025 12:16:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1755864982; bh=/q3BHJ4OBUGrEvfMJAnS4b16x6NbLDJGWQVOq+Cb5uU=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=RtMtEpoYkzibvcasSDr1cZBGonwA9xeXLrKd6nlII8gUQVl/srmYCpDbcv3tFh+Fb 8SbhI+lfZZcfys2PHj1lZWphhfmtGGhQ8ziEGb+8xq02eNCl2NlrFtSD9XgEoqFl3h JmbnT2jcbrwaj5vNpjoamEZTfSGABYeSK4YumRL5vh75Vrzgl6PNTWk9ZsG5t7nJ1x vtZ/af/Hu+tRrFQybTd4N3yGhBuF1MGyYvZPg26Ca1OD5b/n5eaZUu//hcBSu9ldoj xQO9jL9NcYmfT3S93I6gQMwtIOKDnuRe0f/i04kk32XbMlIiTtygxvDjLeo//3YLw5 MUB1YCDswMI2A== From: Andreas Hindborg Date: Fri, 22 Aug 2025 14:14:53 +0200 Subject: [PATCH v6 17/18] rust: block: add remote completion to `Request` Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20250822-rnull-up-v6-16-v6-17-ec65006e2f07@kernel.org> References: <20250822-rnull-up-v6-16-v6-0-ec65006e2f07@kernel.org> In-Reply-To: <20250822-rnull-up-v6-16-v6-0-ec65006e2f07@kernel.org> To: Boqun Feng , Miguel Ojeda , Alex Gaynor , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Alice Ryhl , Trevor Gross , Danilo Krummrich , Jens Axboe , Breno Leitao Cc: linux-block@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, Andreas Hindborg , Daniel Almeida X-Mailer: b4 0.15-dev X-Developer-Signature: v=1; a=openpgp-sha256; l=5096; i=a.hindborg@kernel.org; h=from:subject:message-id; bh=/q3BHJ4OBUGrEvfMJAnS4b16x6NbLDJGWQVOq+Cb5uU=; b=owEBbQKS/ZANAwAIAeG4Gj55KGN3AcsmYgBoqF9B0QbpmE+wvq7lNs2hawy9BgyH6y+HGY1UR /cZqI1GnLqJAjMEAAEIAB0WIQQSwflHVr98KhXWwBLhuBo+eShjdwUCaKhfQQAKCRDhuBo+eShj d+yXEAClAdZfSjB1v1hZEBspjqmjPu3dBNcFRtAtw4vgeFTOO80iQLswPbq3WcZnw1Hcgj3FcrS MjqfMd6z6FToOwvxqKzKNgk8hItYfmvLH+80bnMSCUo7O/im7n+S3V0712mTC9Ov8o0GeBfGlpX pRClqhJlfqRFRGgoMWtRsC8ZTRAaEYzUwck9oRjeeQghp8p23XReudZcMsLeH6tgBnwmEHaFzrF FPHHxdOqvZM6tDQbBQ/6zk4LFoE8P6tFjeZW7KBpqVZRDZhmJchH8ZFDp4J9OmTJFGIFgAM2e0K +ZbAdbK/VIeVg+jp85clymPCMcpS5jEP0co6IHjU6mbZduDeKb7NlvXGQMH7G1Fvo1w3zdvvBpk ZMepeUa+SLCcCPXOFAKbUolS8lIk1UWrVixZFU8Dx3F2iUFzYf4FyJEDY6fhRvT1K86bX1dDuaS UK5H+cq+aM+UuWa3O5pgeRSAPLX6BFBxrDXtLH/m+evMRbd3HMwIKgccXSBQcFyijPDw9lksQN5 GsVowLd3qQr/9UaeuCEowUBe0dDR6smQUwTlWwEk5gYoIc0uTeHpYipEwMVQHJvaPHk8kQRLb34 rmlBPCWcgv/uh7Y9dpn20qlhDMYhlCxpA9h1CHhLl2YNZURVFVQQn/LEycI7gd9f4Tp/0ilgSgU NcFthhlq3DfMNnw== X-Developer-Key: i=a.hindborg@kernel.org; a=openpgp; fpr=3108C10F46872E248D1FB221376EB100563EF7A7 Allow users of rust block device driver API to schedule completion of requests via `blk_mq_complete_request_remote`. Reviewed-by: Alice Ryhl Reviewed-by: Daniel Almeida Signed-off-by: Andreas Hindborg --- drivers/block/rnull/rnull.rs | 9 +++++++++ rust/kernel/block/mq.rs | 6 ++++++ rust/kernel/block/mq/operations.rs | 19 +++++++++++++++---- rust/kernel/block/mq/request.rs | 17 +++++++++++++++++ 4 files changed, 47 insertions(+), 4 deletions(-) diff --git a/drivers/block/rnull/rnull.rs b/drivers/block/rnull/rnull.rs index 8255236bc550..a19c55717c4f 100644 --- a/drivers/block/rnull/rnull.rs +++ b/drivers/block/rnull/rnull.rs @@ -82,4 +82,13 @@ fn queue_rq(_queue_data: (), rq: ARef>, _is_last: bool) -> Res } fn commit_rqs(_queue_data: ()) {} + + fn complete(rq: ARef>) { + mq::Request::end_ok(rq) + .map_err(|_e| kernel::error::code::EIO) + // We take no refcounts on the request, so we expect to be able to + // end the request. The request reference must be unique at this + // point, and so `end_ok` cannot fail. + .expect("Fatal error - expected to be able to end request"); + } } diff --git a/rust/kernel/block/mq.rs b/rust/kernel/block/mq.rs index 6e546f4f3d1c..c0ec06b84355 100644 --- a/rust/kernel/block/mq.rs +++ b/rust/kernel/block/mq.rs @@ -77,6 +77,12 @@ //! } //! //! fn commit_rqs(_queue_data: ()) {} +//! +//! fn complete(rq: ARef>) { +//! Request::end_ok(rq) +//! .map_err(|_e| kernel::error::code::EIO) +//! .expect("Fatal error - expected to be able to end request"); +//! } //! } //! //! let tagset: Arc> = diff --git a/rust/kernel/block/mq/operations.rs b/rust/kernel/block/mq/operations.rs index 6fb256f55acc..0fece577de7c 100644 --- a/rust/kernel/block/mq/operations.rs +++ b/rust/kernel/block/mq/operations.rs @@ -42,6 +42,9 @@ fn queue_rq( /// Called by the kernel to indicate that queued requests should be submitted. fn commit_rqs(queue_data: ForeignBorrowed<'_, Self::QueueData>); + /// Called by the kernel when the request is completed. + fn complete(rq: ARef>); + /// Called by the kernel to poll the device for completed requests. Only /// used for poll queues. fn poll() -> bool { @@ -143,13 +146,21 @@ impl OperationsVTable { T::commit_rqs(queue_data) } - /// This function is called by the C kernel. It is not currently - /// implemented, and there is no way to exercise this code path. + /// This function is called by the C kernel. A pointer to this function is + /// installed in the `blk_mq_ops` vtable for the driver. /// /// # Safety /// - /// This function may only be called by blk-mq C infrastructure. - unsafe extern "C" fn complete_callback(_rq: *mut bindings::request) {} + /// This function may only be called by blk-mq C infrastructure. `rq` must + /// point to a valid request that has been marked as completed. The pointee + /// of `rq` must be valid for write for the duration of this function. + unsafe extern "C" fn complete_callback(rq: *mut bindings::request) { + // SAFETY: This function can only be dispatched through + // `Request::complete`. We leaked a refcount then which we pick back up + // now. + let aref = unsafe { Request::aref_from_raw(rq) }; + T::complete(aref); + } /// This function is called by the C kernel. A pointer to this function is /// installed in the `blk_mq_ops` vtable for the driver. diff --git a/rust/kernel/block/mq/request.rs b/rust/kernel/block/mq/request.rs index 3848cfe63f77..f7f757f7459f 100644 --- a/rust/kernel/block/mq/request.rs +++ b/rust/kernel/block/mq/request.rs @@ -135,6 +135,23 @@ pub fn end_ok(this: ARef) -> Result<(), ARef> { Ok(()) } + /// Complete the request by scheduling `Operations::complete` for + /// execution. + /// + /// The function may be scheduled locally, via SoftIRQ or remotely via IPMI. + /// See `blk_mq_complete_request_remote` in [`blk-mq.c`] for details. + /// + /// [`blk-mq.c`]: srctree/block/blk-mq.c + pub fn complete(this: ARef) { + let ptr = ARef::into_raw(this).cast::().as_ptr(); + // SAFETY: By type invariant, `self.0` is a valid `struct request` + if !unsafe { bindings::blk_mq_complete_request_remote(ptr) } { + // SAFETY: We released a refcount above that we can reclaim here. + let this = unsafe { Request::aref_from_raw(ptr) }; + T::complete(this); + } + } + /// Return a pointer to the [`RequestDataWrapper`] stored in the private area /// of the request structure. /// -- 2.47.2