From mboxrd@z Thu Jan 1 00:00:00 1970 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 9C471C433EF for ; Wed, 1 Dec 2021 13:21:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243852AbhLANYp (ORCPT ); Wed, 1 Dec 2021 08:24:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57874 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234027AbhLANYo (ORCPT ); Wed, 1 Dec 2021 08:24:44 -0500 Received: from mail-wm1-x32d.google.com (mail-wm1-x32d.google.com [IPv6:2a00:1450:4864:20::32d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CBB17C061574 for ; Wed, 1 Dec 2021 05:21:22 -0800 (PST) Received: by mail-wm1-x32d.google.com with SMTP id az34-20020a05600c602200b0033bf8662572so1136807wmb.0 for ; Wed, 01 Dec 2021 05:21:22 -0800 (PST) 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=jSpnMHKvhBQEYOSDHZ4uy6f8JUGZsGZg8bj5CZFIIHw=; b=kC5gcRaO4pNKu2WwkGGRqxUnYarmdtFNfeP2NTeApMKoI0lutD7N1vrXceLV90AImJ 0BNxx4Gh5UWSAySsreIKNOOgTa0rOKGdIt5xsdDQUjmtufZutnB7IG9xxthIiXj+XhWh RmoEbxZQTihIen3nF1j7T6zP+sVmBmJZUojkW5uTOceGpWMYObDr6x5aYDZas97bEXSx YnzXf1kSGlmywAF+wfp9tofGqbFk0qi3iu8bBuALYeUCCZuG7D40zkx0cmFvR1OdYvev eMubnrafmO0owiGX1XJIwY+UziFPKxfzJTMokwbHsqE9J7Js5SpTbA2TzF4S5WyYBBP2 CB2g== 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=jSpnMHKvhBQEYOSDHZ4uy6f8JUGZsGZg8bj5CZFIIHw=; b=Yvk8Er7mqpKPf3cEfJ8UW5StTU7HQlbDeEk28xS4zCnKE7rFV+wI6hRZBYh73D5Uqd 9a2quD2KUm8BmkRDidobBj7AU9usUIMFFAijPgSeePvxiaBgnMhvX0zsDb2pBv0AEvHC 1DPalTXlds+IxGO2at7tQwHDT2OyFmUbWBDhbRVLTfj9lnll1dYI1w8MQ+A5u4Kl+jd3 i+nw+LzVdyD7aYBKqQB4U7fcbJNxEgHm96nZ6/MtDMl8uaPhcYf8eQQj/9zgy+S+kn3E DbTPyvPfGlgAntfDLrkkEgz8brC+nCF3hxf682/98Lzqc12ea+sF/rYdxDvF92FckqRG AAag== X-Gm-Message-State: AOAM530JB16BOM56Q1pKixRHLWBvOn+Vzmsu6dzfwWpj3i1RZc7EUtaE L47TV8UQukDgb3D9ps7mUQhxT9N3wBE= X-Google-Smtp-Source: ABdhPJwG1LmqeSATZqdklddWENRtVA/tX4K5yzVCEN38EUK6ZwHfzzepzSxAQNLC+KwFVYlGojcq2A== X-Received: by 2002:a1c:80c5:: with SMTP id b188mr7198557wmd.57.1638364881212; Wed, 01 Dec 2021 05:21:21 -0800 (PST) Received: from 127.0.0.1localhost (82-132-231-182.dab.02.net. [82.132.231.182]) by smtp.gmail.com with ESMTPSA id d2sm1103929wmb.31.2021.12.01.05.21.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 01 Dec 2021 05:21:20 -0800 (PST) From: Pavel Begunkov To: io-uring@vger.kernel.org Cc: asml.silence@gmail.com Subject: [PATCH liburing 1/1] man/io_uring_enter.2: notes about cqe-skip & drain interoperability Date: Wed, 1 Dec 2021 13:20:37 +0000 Message-Id: <8c81bf9b01a54d1214bb65678c2ff1362a9f9328.1638364791.git.asml.silence@gmail.com> X-Mailer: git-send-email 2.34.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org IOSQE_CQE_SKIP_SUCCESS can't be used together with draining in a single ring, add a paragraph explaining what are the restrictions. Signed-off-by: Pavel Begunkov --- man/io_uring_enter.2 | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/man/io_uring_enter.2 b/man/io_uring_enter.2 index b003e05..871cbce 100644 --- a/man/io_uring_enter.2 +++ b/man/io_uring_enter.2 @@ -1115,6 +1115,15 @@ CQEs in cases where the side effects of a successfully executed operation is enough for userspace to know the state of the system. One such example would be writing to a synchronisation file. +It also doesn't work with +.B IOSQE_IO_DRAIN. +Using both of them in a ring is undefined behaviour even when they never appear +together in a single request. Currently, after first request with +.B IOSQE_CQE_SKIP_SUCCESS, +all subsequent requests marked for drain will be failed. However, the +error reporting is best effort only and restrictions may change in +the future. + Available since 5.17. .PP -- 2.34.0