From patchwork Fri Jul 22 11:49:02 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Begunkov X-Patchwork-Id: 12926403 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1E51CC433EF for ; Fri, 22 Jul 2022 11:50:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233608AbiGVLu1 (ORCPT ); Fri, 22 Jul 2022 07:50:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48342 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230151AbiGVLu0 (ORCPT ); Fri, 22 Jul 2022 07:50:26 -0400 Received: from mail-wm1-x334.google.com (mail-wm1-x334.google.com [IPv6:2a00:1450:4864:20::334]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 40AD53343D for ; Fri, 22 Jul 2022 04:50:25 -0700 (PDT) Received: by mail-wm1-x334.google.com with SMTP id v67-20020a1cac46000000b003a1888b9d36so5046835wme.0 for ; Fri, 22 Jul 2022 04:50:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=HT6qpwF9Y4ADTJ8y2fUqQ9kABRQnIh/m7aED+Ze69tA=; b=TVD0akM9PBYGGPrDIWLRo9vVjfuNK1RKPiH0vrG8Ft9SjpIsbZiPOeYtcyWi7tQHmP FMdwRrqyj5FUkn1gZaxOzeu63oVfpJ0BLjjX7OKQMVqZq5FAaaDBx3hU6CURP+9R0xxI mWLEhg6cI5NLW9C7G64N5hJpFXKTOgNfRiwsafIEprJSdtttssgXV/5drMyCSehhTlm2 ywhkCnkR4f3Q8quOKUxUPZ3iqa13bzt+D5fjwfzni+sq14tIcO9OkQ58DmesPWVeLEsm Bd27wq6s7sd3DVYxF9x+Ml9+MPC9S4ifyfSsetEtE4OqPvGrjN71mCnQUp66QkBByz0/ Wcrw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=HT6qpwF9Y4ADTJ8y2fUqQ9kABRQnIh/m7aED+Ze69tA=; b=ijxIB4/xxGCgQXD+yF5zDf2cTCCj/EnQZbeyv0HTr3RNt6rJY8iPLViacdzOsQ+VqJ BAMiln37ZZjpuWCziBwmAjCspA80vP31UM/k7mMzIdcVi6fvv60ZjLwJK3/qRG35zl4V iCPqvBpsnQMvaobBFSQN7OI3cFU6Z/BPQHa7Gphl/L8FGVqQCnIwieLSgS89Cytkhgvb VMc5Fy4XUcPZVsHEeOqtVyqumWeMNOjIYm1TExdhbLlYX5wYIZFKPUZKRgyrcJItnVTs TqPImYjWLloUqn/ouWka8cjxSDTZv/SY7PJEQZKSOzeWpZr6efb0qTz/3pc0WqEIiuqW dhGg== X-Gm-Message-State: AJIora9luE7Rb+uiE4Zi4RSEWRMDobDS7esqTdrkpf4qlFTaAIsaFzc7 zTkzpDar8TFwsJ5IJKEYubaNtQJPBde00w== X-Google-Smtp-Source: AGRyM1vUoUty1bMMYft2ZPL/lDkwsRASHeKj7Tr/ASNM+l+ywwfuoUTc3I66PdovT8ebrzORgCyGPA== X-Received: by 2002:a05:600c:4e12:b0:3a3:2fe2:7d0e with SMTP id b18-20020a05600c4e1200b003a32fe27d0emr7026733wmq.151.1658490623116; Fri, 22 Jul 2022 04:50:23 -0700 (PDT) Received: from 127.0.0.1localhost.com ([2620:10d:c092:600::2:a3d]) by smtp.gmail.com with ESMTPSA id k20-20020a05600c1c9400b003a31fd05e0fsm18257853wms.2.2022.07.22.04.50.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 22 Jul 2022 04:50:22 -0700 (PDT) From: Pavel Begunkov To: io-uring@vger.kernel.org Cc: Jens Axboe , asml.silence@gmail.com Subject: [PATCH liburing 1/1] man/io_uring_setup.2: document IORING_SETUP_SINGLE_ISSUER Date: Fri, 22 Jul 2022 12:49:02 +0100 Message-Id: <9e282a50456df4451e28189bd3ac6e54d598ecc3.1658490521.git.asml.silence@gmail.com> X-Mailer: git-send-email 2.37.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org Signed-off-by: Pavel Begunkov --- man/io_uring_setup.2 | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/man/io_uring_setup.2 b/man/io_uring_setup.2 index 75c69ff..0f57d8f 100644 --- a/man/io_uring_setup.2 +++ b/man/io_uring_setup.2 @@ -239,6 +239,24 @@ variant. This is a requirement for using certain request types, as of 5.19 only the .B IORING_OP_URING_CMD passthrough command for NVMe passthrough needs this. Available since 5.19. +.TP +.B IORING_SETUP_SINGLE_ISSUER +A hint to the kernel that only a single task can submit requests, which is used +for internal optimisations. The kernel enforces the rule, which only affects +.I +io_uring_enter(2) +calls submitting requests and will fail them with +.B -EEXIST +if the restriction is violated. +The submitter task may differ from the task that created the ring. +Note that when +.B IORING_SETUP_SQPOLL +is set it is considered that the polling task is doing all submissions +on behalf of the userspace and so it always complies with the rule disregarding +how many userspace tasks do +.I +io_uring_enter(2). +Available since 5.20. .PP If no flags are specified, the io_uring instance is setup for interrupt driven I/O. I/O may be submitted using