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=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, 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 D9636C2D0CD for ; Wed, 18 Dec 2019 17:18:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B23692082E for ; Wed, 18 Dec 2019 17:18:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="zF0PTpKs" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727137AbfLRRSz (ORCPT ); Wed, 18 Dec 2019 12:18:55 -0500 Received: from mail-io1-f68.google.com ([209.85.166.68]:42442 "EHLO mail-io1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726996AbfLRRSz (ORCPT ); Wed, 18 Dec 2019 12:18:55 -0500 Received: by mail-io1-f68.google.com with SMTP id n11so1250564iom.9 for ; Wed, 18 Dec 2019 09:18:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=yYrBHxXYiIqMn7AyRM7VutEfqO7rU2p+V8uEiPaEELo=; b=zF0PTpKsiBo0vPQX7SwAajHnVDffHFrLeRquX4ty2BsNrIEJK/xeFJDEYS7iGFOCSi VkEr4zahxTs0fjW2dbarecpseSWcw8zKyDm7Ew8YzIiXRALZeVcEg+ZQZwpxfqbCq+jT IsImYzgYM/sWNWnw0n1ITr740vlPpCG1ods+mCtE+Eics0kR6vJOrm/wVvBdwCp+pMAG wL5oT8JHPbwBRXynRNFBt/n35+6KOUaBsojWKSm8oiSmzgbB+jJgJNTojehG4Phc5Q6Z TQsYFH1+oavMqYjeP9zT1ajlrX5kMPKAqva/l0Ud9iKDMcsh1+Lm6Bj6S9V08TH6hLrE U83A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=yYrBHxXYiIqMn7AyRM7VutEfqO7rU2p+V8uEiPaEELo=; b=MN/wja/k/hgwuJvqMsdeWjI8G0InhUqKyvBb1fJ4UlmxFBmWu++3NAJiklLVsR9K0D qCY/K+/EfvmUnrMAzi+DrPNGMy51YJZXpCHLlm6oIJWE0sANEbCOmYyt3Ej29QVRg3hD LyRdTR/c/mJxe1VIquK3NBINdihmfkWONBMDt1RMuH6xK8q+ddymIf+AOb04+XPXz9BO hfQMYPkX26P7tQGMNU60uANSC1N+0rd/SJe5fLNcavb8Ag2dXH+riBqBICdsewUwggS+ ml/+o55zAuABKqFOVDXz1eLyDe5G075FfeXUh2vfKvEm76bvI4KGB/Pbd+CTxeUrD119 OYow== X-Gm-Message-State: APjAAAXjbcdfGRXR+cQuNMtqe6KC/jJWRE5Ru1aywYvPNEdtR6X1G9DC maxKmAMHXO7otrXf0oa/wA1HZ6Sp5d8AkQ== X-Google-Smtp-Source: APXvYqzoOVRr62rAtCafcWIWDAIJCEiVPJV++DBN8nFqsM7nx+nmQDfSXXLCA9X+6PUau7CqHuHPew== X-Received: by 2002:a5e:c601:: with SMTP id f1mr2580631iok.208.1576689534581; Wed, 18 Dec 2019 09:18:54 -0800 (PST) Received: from x1.thefacebook.com ([65.144.74.34]) by smtp.gmail.com with ESMTPSA id o12sm577488ioh.42.2019.12.18.09.18.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Dec 2019 09:18:54 -0800 (PST) From: Jens Axboe To: io-uring@vger.kernel.org Cc: Pavel Begunkov , Jens Axboe Subject: [PATCH 13/13] io_uring: don't wait when under-submitting Date: Wed, 18 Dec 2019 10:18:35 -0700 Message-Id: <20191218171835.13315-14-axboe@kernel.dk> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191218171835.13315-1-axboe@kernel.dk> References: <20191218171835.13315-1-axboe@kernel.dk> 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 From: Pavel Begunkov 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 Signed-off-by: Jens Axboe --- fs/io_uring.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/io_uring.c b/fs/io_uring.c index 74dc9de94117..b7800def3090 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); -- 2.24.1