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 287B22E3717; Fri, 15 Aug 2025 07:32:21 +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=1755243142; cv=none; b=HeXtdDIzRqQy+sfYwyirZEUopXEycszb6UmDLN3AsJxw0rAkc6JtoDfMe0kXNeKR4lBMc5fjdXW3QvL2yP1H4qAsIm6tFpNUQ9t1c3rjEwI/XYPYuSX6xrc8y9JGDnsbRmfCfoRsTE+ycN5W07HyEfnkBF9xSfUVpRwVG8k1cRg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755243142; c=relaxed/simple; bh=ptlSB6M90/rSSKcTITvpEJrxVHE1Cq2YggkTtF+7zuo=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=ZD63QtOl4R7oVfkAKmuB4CYaZwZwqH9sVTQFPtlhLSaFW/NLBZooB5W9JlfgTpQ8ud+sJytGqCwqVqlltuOI9acjncIrEgtDAKHn7i7Eng+iz5CfblT1xR5B0fbYFJRbW6aO6LxtivsQ3MV9AfmVvAuEQGE615rB7/gUxeIUfA8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XoZljY9L; 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="XoZljY9L" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D62D3C4CEF4; Fri, 15 Aug 2025 07:32:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1755243141; bh=ptlSB6M90/rSSKcTITvpEJrxVHE1Cq2YggkTtF+7zuo=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=XoZljY9Ldj/5cPq5m0vhHaIgNOEzPK8va33By5BX1vTY+rJc7R+8Kt+S6L61VIPw1 k+hhYiduVKs1zhiVUPitROCIhFuXPmJTaxtllbJ1k29fB0Ooab5gUOGqElsX2yMHgf 3xIuHt4MShJ0mm16uc832iBEJFgWr4PqSArSzAwxuxfK28jrZ4QLyGRSaEdUM8p1um 09OCoa7mJkocvNp3iaDOgNpPquPbFgwouTikJR5lRNgndBB2BaHtR/FCKbHW8TPZ4I zOC+EC5GJBg4huzzSU2hApsZag/Y/MxfYlH2x1zz7HCDJuCtHLssNCzrxqI/wIt5GQ pJjzHVHQKBkVg== From: Andreas Hindborg Date: Fri, 15 Aug 2025 09:30:52 +0200 Subject: [PATCH v5 17/18] 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: <20250815-rnull-up-v6-16-v5-17-581453124c15@kernel.org> References: <20250815-rnull-up-v6-16-v5-0-581453124c15@kernel.org> In-Reply-To: <20250815-rnull-up-v6-16-v5-0-581453124c15@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=ptlSB6M90/rSSKcTITvpEJrxVHE1Cq2YggkTtF+7zuo=; b=owEBbQKS/ZANAwAIAeG4Gj55KGN3AcsmYgBonuJDRbh+iYUm3B/Rl8pnd7/DbU4talFphY1OV GNtK+xAov+JAjMEAAEIAB0WIQQSwflHVr98KhXWwBLhuBo+eShjdwUCaJ7iQwAKCRDhuBo+eShj dxUOD/90P0qxled8tMgqTvZrwRFsQm2CK0mivxqCFoCrMruKHcUiMTXV/CxqiskJGYqYCkpkBCH etAlWuhoqjnhjXloLMEYN6ekPg7Wbr8xuO1fWfIC5tBq7AlGFYSIYqHzpgIpui9IxOSjpPug6SO 6YqbDCfc0TdmQiUwe03PMMzrVTm9v6kiKHQ/ZKJviSf16AGZlfMSbcfo97vqK/WRd9C8xV9wSp2 aqQtk/rmPyVYYKKm+Du1OetqntcnRi8flT4VkBqTytugIXk2midRXZo+5eu6ts07GQHHCxdgs2z Pedh+fJ13dqN3sJogGoH1GHZglTbrgpEEvGLP+OpC1mEAyRs7p74IpYUTM+WEKsKf1r0Sgcknxh 8Vk55GWdiF3HEHSgAaJWAg1wsJKN9TKINx6aI/ZEHWGLNH2iVnjiua3EmQ/AtNB5C14J5+R/bx/ dfBXSurWbO6YfneqXIRqQTutvTV5su03B2pApa/82fPw0Klph7aEQYdIEYe2k0/rDpcUO8OHsS4 tqXbGQbf7KgeG39yRehlOe3JqO78/hNBADBR3ne4VWYYCN1LoeGroim1jgrqxNEmFIZeJ5yhrgb pHySvaZnkCzl8StpnU4+8vGAJRSimdSjD9QKOkB6lySWBgIJ3wTqt8XIi5jnioRvviNlAQQyhf/ joinvrE3NcOQ18A== 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 a012c59ecb3c..371786be7f47 100644 --- a/drivers/block/rnull/rnull.rs +++ b/drivers/block/rnull/rnull.rs @@ -83,4 +83,13 @@ 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