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 051922F1FE7; Tue, 2 Sep 2025 09:55:54 +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=1756806955; cv=none; b=KBvL4cdaCRZt2EMN84XS0v85dXzPqbhIQ9ITxU3vkhRMKJ4SHifmSZ6+xDSvrOXZ1MA8F8Ny6ch8GgixmQlihhDmGAfq6LmuJZVpybpeb8ePSMg9D1cJkvAsdXFTZU+5AE8eGlA3cKGQL0B0ETsP9sQz/HNnQQllbyR3k8NGHds= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756806955; c=relaxed/simple; bh=YwUF3HJQztP31Vw7ZaxJ69OuXp+5+j2Zu1cR8QzNe+g=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=HkjmrcZ/7N/QR1+kzVGhgAlpc7FjoZOuR6pyCNryHV5sujXkRAH8cB8H0uhQShrgZ6P/7vdhCc0B40BreamY1KUbd5ChXdlv4aK29d5cAsZAsPZd7hiQZWV+R5xDcz1dhe3gNbqwJvLVqVUkfH/zoqabb6K8OLIOYihWb+ckUv4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ck9dwNAN; 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="Ck9dwNAN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6FFA2C4CEED; Tue, 2 Sep 2025 09:55:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1756806954; bh=YwUF3HJQztP31Vw7ZaxJ69OuXp+5+j2Zu1cR8QzNe+g=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=Ck9dwNANve8Ne07xu+AirZzR2EBbPSww8ib2Vc8HjgubaHxLCmRmMZ1hCtNta5ipZ PwY+nMPI7lp/yvz6I2fpQz1GZ+4pH8h4P2VZzkcv/z9D0gy5Xokj9hAtxDfrO0zIa8 +5lsuG404qojoocZrC6Sp+6qhK6MJ4AJba1OBNoso1PneKZckOiyKiUs58w1tkfsFu nkZ0t6KLNCMbjNPoMERvwyHf4iwXjM4w1/rb/5gAJCAPWmdrAIF2aNY895V9nbP+GO yvY5dpHycAe2i/7b64wMtPyWItWvPh7BkDJZeM+c/b9XMPB+u6B2bcz93Ho9HsxluF 4N1zDc+WaJ3zw== From: Andreas Hindborg Date: Tue, 02 Sep 2025 11:55:10 +0200 Subject: [PATCH v7 16/17] rust: block: add remote completion to `Request` Precedence: bulk X-Mailing-List: rust-for-linux@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: <20250902-rnull-up-v6-16-v7-16-b5212cc89b98@kernel.org> References: <20250902-rnull-up-v6-16-v7-0-b5212cc89b98@kernel.org> In-Reply-To: <20250902-rnull-up-v6-16-v7-0-b5212cc89b98@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=YwUF3HJQztP31Vw7ZaxJ69OuXp+5+j2Zu1cR8QzNe+g=; b=owEBbQKS/ZANAwAIAeG4Gj55KGN3AcsmYgBotr8HVoiFEohNXcMvJ10o1RLWE0ZZxSrQFCEj7 KsX6wNYVOuJAjMEAAEIAB0WIQQSwflHVr98KhXWwBLhuBo+eShjdwUCaLa/BwAKCRDhuBo+eShj d432D/4zM1sRmiacMnsFNRMn96mFZy6dtbiRextv5n51Q1z+n+WKRdCnPqqkm9nDvocudZE8PQ/ OIJOfwZCMsDwUnDUhFU3TzR+61GK0PhdxslCeBy6LrHnWZqw+mjsm5WSXV94EehtZCsejiedItR 4hsKAjFt+dYfWkEOQBSyyang5iott/7IyABtmM4iAHnvLGxrLp+/xPfk4217EyvtS8oOOWK40EJ 7YUhy0U2T53IyTZ1bbhgZv3eH/gTQGqtHVKK7sMrBeuz+vCAR7Br15qgdLsWC5MvdhPk6BkKPK6 CTYs/TzSw9Jl8JvrUGKwIJqld+rpTwwoIAALQnnS8LFDCvA3yNmOyCS4T02cyzSS9fiIIfxDG+e SNmRWhccoF5f7m1Ppx6gj3mmSf+ljv9gUXXFpXJ37/LZNYRhVCUr7iHUpo+po3eiY37siNQ7toz 6+yGzbUWAvszqfwGpQXTDH0kCFRK6irveEKzSh3IAnHP+b6x0pZhDBGDTg2CgY7MwJzNLwDAiWX V4h62DDs3Jxvzfe6SbOfePNwb4I6/9hP1dKeDG3DNm3sJLBJLUFVj92hxVEiMCKW2zogFzHofzu 1ZKdzyVrGAMekKGQASkz+6dZupYftF6jCTsbkGxSCQ7XJhQIj7ypEe8SzlNKW6GrZKHBtLWe3A/ m/vRrgl4jESHYpQ== 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 9e31d24e1164..d098a8a3e434 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