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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,UNPARSEABLE_RELAY, URIBL_BLOCKED,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 9CD5EC43381 for ; Thu, 21 Mar 2019 13:18:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 69B55218FF for ; Thu, 21 Mar 2019 13:18:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728395AbfCUNSh (ORCPT ); Thu, 21 Mar 2019 09:18:37 -0400 Received: from mail-il-dmz.mellanox.com ([193.47.165.129]:42416 "EHLO mellanox.co.il" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728362AbfCUNSd (ORCPT ); Thu, 21 Mar 2019 09:18:33 -0400 Received: from Internal Mail-Server by MTLPINE1 (envelope-from vladbu@mellanox.com) with ESMTPS (AES256-SHA encrypted); 21 Mar 2019 15:18:26 +0200 Received: from reg-r-vrt-018-180.mtr.labs.mlnx. (reg-r-vrt-018-180.mtr.labs.mlnx [10.213.18.180]) by labmailer.mlnx (8.13.8/8.13.8) with ESMTP id x2LDIPdS019148; Thu, 21 Mar 2019 15:18:26 +0200 From: Vlad Buslov To: netdev@vger.kernel.org Cc: jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us, davem@davemloft.net, sbrivio@redhat.com, Vlad Buslov Subject: [PATCH net-next v3 09/12] net: sched: flower: handle concurrent tcf proto deletion Date: Thu, 21 Mar 2019 15:17:41 +0200 Message-Id: <20190321131744.19224-10-vladbu@mellanox.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190321131744.19224-1-vladbu@mellanox.com> References: <20190321131744.19224-1-vladbu@mellanox.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Without rtnl lock protection tcf proto can be deleted concurrently. Check tcf proto 'deleting' flag after taking tcf spinlock to verify that no concurrent deletion is in progress. Return EAGAIN error if concurrent deletion detected, which will cause caller to retry and possibly create new instance of tcf proto. Retry mechanism is a result of fine-grained locking approach used in this and previous changes in series and is necessary to allow concurrent updates on same chain instance. Alternative approach would be to lock the whole chain while updating filters on any of child tp's, adding and removing classifier instances from the chain. However, since most CPU-intensive parts of filter update code are specifically in classifier code and its dependencies (extensions and hw offloads), such approach would negate most of the gains introduced by this change and previous changes in the series when updating same chain instance. Signed-off-by: Vlad Buslov Reviewed-by: Stefano Brivio --- net/sched/cls_flower.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c index 70b357f23391..25a4d64b82db 100644 --- a/net/sched/cls_flower.c +++ b/net/sched/cls_flower.c @@ -1500,6 +1500,14 @@ static int fl_change(struct net *net, struct sk_buff *in_skb, if (!tc_in_hw(fnew->flags)) fnew->flags |= TCA_CLS_FLAGS_NOT_IN_HW; + /* tp was deleted concurrently. -EAGAIN will cause caller to lookup + * proto again or create new one, if necessary. + */ + if (tp->deleting) { + err = -EAGAIN; + goto errout_hw; + } + refcount_inc(&fnew->refcnt); if (fold) { /* Fold filter was deleted concurrently. Retry lookup. */ -- 2.21.0