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 X-Spam-Level: X-Spam-Status: No, score=-9.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 75A61C43603 for ; Wed, 18 Dec 2019 16:54:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 44152218AC for ; Wed, 18 Dec 2019 16:54:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="FtT2G1x8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727173AbfLRQyT (ORCPT ); Wed, 18 Dec 2019 11:54:19 -0500 Received: from mail-wr1-f67.google.com ([209.85.221.67]:37663 "EHLO mail-wr1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727217AbfLRQyS (ORCPT ); Wed, 18 Dec 2019 11:54:18 -0500 Received: by mail-wr1-f67.google.com with SMTP id w15so3073700wru.4; Wed, 18 Dec 2019 08:54:17 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:subject:date:message-id:in-reply-to:references:mime-version :content-transfer-encoding; bh=EP911nSLn2Vvgh6u3IlrfunDIUtinbfht576MeZl9vU=; b=FtT2G1x8vmq1aKeLKcwZ5GBfDHbyrFavKKLhVNJSLjA/Vy3lRtlVd5934szOsrXvNg M2Xhp0XSR0aQUZmsjZZuH+php++4yCfNvadeV9zhrU9BeYEu0d0Qcuxo2fk6JfHnwQNm xEOOgsRk0NgpiVTuL47wlHJE2w1qZUvIBG/9BnxW3PSqN++a/VUOA2Zcb+2cFu5fOOUq ttokrTaIDWxZgT79HXyyhts2bJdkQorLu5Fvcf1gVgqh0Z2jaYu4rqBG8VCd4t28Tg/H Qzs+NRkJEgpv5zy96hZMtgoKsh2OIBdEdVFLXqhEY6mmBpKXDU81a6F7mKVe//mHyXM2 5QlQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=EP911nSLn2Vvgh6u3IlrfunDIUtinbfht576MeZl9vU=; b=hWcnFcN2uZHDzdT8etDq9ZbTTMJKb9B0pKg12hdldedndPQhAD8fxkHP+8IB8cfEMw 7fmHXc64q1vgvuMxjrYHStj6cYc7lE5lQmmGDYCNBzziWBZvilr0Q4QBs8JuKsS02Fvw qvHBVSZtTqGX+5FyAL7j+0xL5tK4UBZgtL7mZqQfxXJNVfI+DWziCqlWe3w0J6PSLKxa Mg50Gbj4k9eqKShrG1EEp6BmUcfL5seCMHVojQ3wKoDFBOc1D0DFwwln6d9faiccPuXX uMFtIWNAA2+O4gX4+kKL3vm5ynqEc8nJQjnCm+8Xay8J5BuTDvHe0zm07JSn8W716Dt2 hWSg== X-Gm-Message-State: APjAAAWnHuOc7MigQVo/DX8ahA0ms2WsTohbJYk1aoX41hEk5aXh0h8Y X7CZBqoNmlYSvQmLz2GgvmjAWXFQ X-Google-Smtp-Source: APXvYqwqthIIeClNPYTweeerQmwMsf4UH7HXj0fEs3V0m5z5QScsmpyr+r082e5y7lVS0NNF1Cf4gQ== X-Received: by 2002:adf:fbc9:: with SMTP id d9mr4097279wrs.20.1576688056522; Wed, 18 Dec 2019 08:54:16 -0800 (PST) Received: from localhost.localdomain ([109.126.149.134]) by smtp.gmail.com with ESMTPSA id b17sm3152856wrp.49.2019.12.18.08.54.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Dec 2019 08:54:16 -0800 (PST) From: Pavel Begunkov To: Jens Axboe , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v5] io_uring: don't wait when under-submitting Date: Wed, 18 Dec 2019 19:53:45 +0300 Message-Id: <28aad565ed6c3a3a03975377aa62035b1b0a4d97.1576687827.git.asml.silence@gmail.com> X-Mailer: git-send-email 2.24.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org There is no reliable way to submit and wait in a single syscall, as io_submit_sqes() may under-consume sqes (in case of an early error). Then it will wait for not-yet-submitted requests, deadlocking the user in most cases. Don't wait/poll if can't submit all sqes Signed-off-by: Pavel Begunkov --- v5: as the v1, but doesn't return -EAGAIN fs/io_uring.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/io_uring.c b/fs/io_uring.c index fd85f9d3a8e1..eca025f38614 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -5133,6 +5133,9 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, submitted = io_submit_sqes(ctx, to_submit, f.file, fd, &cur_mm, false); mutex_unlock(&ctx->uring_lock); + + if (submitted != to_submit) + goto out; } if (flags & IORING_ENTER_GETEVENTS) { unsigned nr_events = 0; @@ -5146,6 +5149,7 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, } } +out: percpu_ref_put(&ctx->refs); out_fput: fdput(f); -- 2.24.0