{"id":810689,"url":"http://patchwork.ozlabs.org/api/1.2/patches/810689/?format=json","web_url":"http://patchwork.ozlabs.org/project/openvswitch/patch/20170906155745.1031-1-blp@ovn.org/","project":{"id":47,"url":"http://patchwork.ozlabs.org/api/1.2/projects/47/?format=json","name":"Open vSwitch","link_name":"openvswitch","list_id":"ovs-dev.openvswitch.org","list_email":"ovs-dev@openvswitch.org","web_url":"http://openvswitch.org/","scm_url":"git@github.com:openvswitch/ovs.git","webscm_url":"https://github.com/openvswitch/ovs","list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20170906155745.1031-1-blp@ovn.org>","list_archive_url":null,"date":"2017-09-06T15:57:45","name":"[ovs-dev] dpif-netdev: Avoid side-effect in argument of atomic_store_relaxed().","commit_ref":null,"pull_url":null,"state":"accepted","archived":false,"hash":"142c04745a740e5e782d0219656cf1d684c2f56d","submitter":{"id":67603,"url":"http://patchwork.ozlabs.org/api/1.2/people/67603/?format=json","name":"Ben Pfaff","email":"blp@ovn.org"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/openvswitch/patch/20170906155745.1031-1-blp@ovn.org/mbox/","series":[{"id":1846,"url":"http://patchwork.ozlabs.org/api/1.2/series/1846/?format=json","web_url":"http://patchwork.ozlabs.org/project/openvswitch/list/?series=1846","date":"2017-09-06T15:57:45","name":"[ovs-dev] dpif-netdev: Avoid side-effect in argument of atomic_store_relaxed().","version":1,"mbox":"http://patchwork.ozlabs.org/series/1846/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/810689/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/810689/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":["incoming@patchwork.ozlabs.org","dev@openvswitch.org"],"Delivered-To":["patchwork-incoming@bilbo.ozlabs.org","ovs-dev@mail.linuxfoundation.org"],"Authentication-Results":"ozlabs.org;\n\tspf=pass (mailfrom) smtp.mailfrom=openvswitch.org\n\t(client-ip=140.211.169.12; helo=mail.linuxfoundation.org;\n\tenvelope-from=ovs-dev-bounces@openvswitch.org;\n\treceiver=)","Received":["from mail.linuxfoundation.org (mail.linuxfoundation.org\n\t[140.211.169.12])\n\t(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256\n\tbits)) (No client certificate requested)\n\tby ozlabs.org (Postfix) with ESMTPS id 3xnSsk6Cb7z9t4s\n\tfor ;\n\tThu, 7 Sep 2017 01:58:02 +1000 (AEST)","from mail.linux-foundation.org (localhost [127.0.0.1])\n\tby mail.linuxfoundation.org (Postfix) with ESMTP id 3ACAFAE1;\n\tWed, 6 Sep 2017 15:57:59 +0000 (UTC)","from smtp1.linuxfoundation.org (smtp1.linux-foundation.org\n\t[172.17.192.35])\n\tby mail.linuxfoundation.org (Postfix) with ESMTPS id D5A98AC8\n\tfor ; Wed, 6 Sep 2017 15:57:57 +0000 (UTC)","from relay6-d.mail.gandi.net (relay6-d.mail.gandi.net\n\t[217.70.183.198])\n\tby smtp1.linuxfoundation.org (Postfix) with ESMTPS id 45E20433\n\tfor ; Wed, 6 Sep 2017 15:57:57 +0000 (UTC)","from sigabrt.benpfaff.org (unknown [208.91.2.3])\n\t(Authenticated sender: blp@ovn.org)\n\tby relay6-d.mail.gandi.net (Postfix) with ESMTPSA id A8E80FB8B1;\n\tWed, 6 Sep 2017 17:57:53 +0200 (CEST)"],"X-Greylist":"domain auto-whitelisted by SQLgrey-1.7.6","X-Originating-IP":"208.91.2.3","From":"Ben Pfaff ","To":"dev@openvswitch.org","Date":"Wed, 6 Sep 2017 08:57:45 -0700","Message-Id":"<20170906155745.1031-1-blp@ovn.org>","X-Mailer":"git-send-email 2.10.2","X-Spam-Status":"No, score=-0.7 required=5.0 tests=RCVD_IN_DNSWL_LOW\n\tautolearn=disabled version=3.3.1","X-Spam-Checker-Version":"SpamAssassin 3.3.1 (2010-03-16) on\n\tsmtp1.linux-foundation.org","Cc":"Ben Pfaff , Alin Serdean ","Subject":"[ovs-dev] [PATCH] dpif-netdev: Avoid side-effect in argument of\n\tatomic_store_relaxed().","X-BeenThere":"ovs-dev@openvswitch.org","X-Mailman-Version":"2.1.12","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","MIME-Version":"1.0","Content-Type":"text/plain; charset=\"us-ascii\"","Content-Transfer-Encoding":"7bit","Sender":"ovs-dev-bounces@openvswitch.org","Errors-To":"ovs-dev-bounces@openvswitch.org"},"content":"Some of the implementations of atomic_store_relaxed() evaluate their\nfirst argument more than once, so arguments with side effects cause\nstrange behavior. This fixes a problem observed on 64-bit Windows.\n\nReported-by: Alin Serdean \nSigned-off-by: Ben Pfaff \n---\n lib/dpif-netdev.c | 4 ++--\n 1 file changed, 2 insertions(+), 2 deletions(-)","diff":"diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c\nindex 071ec141f1d1..0ceef9d82914 100644\n--- a/lib/dpif-netdev.c\n+++ b/lib/dpif-netdev.c\n@@ -3201,8 +3201,8 @@ static void\n dp_netdev_rxq_set_intrvl_cycles(struct dp_netdev_rxq *rx,\n unsigned long long cycles)\n {\n- atomic_store_relaxed(&rx->cycles_intrvl[rx->intrvl_idx++\n- % PMD_RXQ_INTERVAL_MAX], cycles);\n+ unsigned int idx = rx->intrvl_idx++ % PMD_RXQ_INTERVAL_MAX;\n+ atomic_store_relaxed(&rx->cycles_intrvl[idx], cycles);\n }\n \n static uint64_t\n","prefixes":["ovs-dev"]}