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=-12.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 8B797C10DAA for ; Wed, 9 Sep 2020 09:43:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3575921973 for ; Wed, 9 Sep 2020 09:43:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727782AbgIIJn3 (ORCPT ); Wed, 9 Sep 2020 05:43:29 -0400 Received: from correo.us.es ([193.147.175.20]:34868 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729719AbgIIJmh (ORCPT ); Wed, 9 Sep 2020 05:42:37 -0400 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id 36B652EFEBC for ; Wed, 9 Sep 2020 11:42:31 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 07A8BDA730 for ; Wed, 9 Sep 2020 11:42:31 +0200 (CEST) Received: by antivirus1-rhel7.int (Postfix, from userid 99) id EE830DA73D; Wed, 9 Sep 2020 11:42:30 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id B343ADA730; Wed, 9 Sep 2020 11:42:28 +0200 (CEST) Received: from 192.168.1.97 (192.168.1.97) by antivirus1-rhel7.int (F-Secure/fsigk_smtp/550/antivirus1-rhel7.int); Wed, 09 Sep 2020 11:42:28 +0200 (CEST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/antivirus1-rhel7.int) Received: from localhost.localdomain (unknown [90.77.255.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: pneira@us.es) by entrada.int (Postfix) with ESMTPSA id 7308A4301DED; Wed, 9 Sep 2020 11:42:28 +0200 (CEST) X-SMTPAUTHUS: auth mail.us.es From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: davem@davemloft.net, netdev@vger.kernel.org Subject: [PATCH 07/13] netfilter: conntrack: remove unneeded nf_ct_put Date: Wed, 9 Sep 2020 11:42:13 +0200 Message-Id: <20200909094219.17732-8-pablo@netfilter.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200909094219.17732-1-pablo@netfilter.org> References: <20200909094219.17732-1-pablo@netfilter.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Virus-Scanned: ClamAV using ClamSMTP Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org From: Florian Westphal We can delay refcount increment until we reassign the existing entry to the current skb. A 0 refcount can't happen while the nf_conn object is still in the hash table and parallel mutations are impossible because we hold the bucket lock. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_core.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index 93e77ca0efad..234b7cab37c3 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -908,6 +908,7 @@ static void __nf_conntrack_insert_prepare(struct nf_conn *ct) tstamp->start = ktime_get_real_ns(); } +/* caller must hold locks to prevent concurrent changes */ static int __nf_ct_resolve_clash(struct sk_buff *skb, struct nf_conntrack_tuple_hash *h) { @@ -921,13 +922,12 @@ static int __nf_ct_resolve_clash(struct sk_buff *skb, if (nf_ct_is_dying(ct)) return NF_DROP; - if (!atomic_inc_not_zero(&ct->ct_general.use)) - return NF_DROP; - if (((ct->status & IPS_NAT_DONE_MASK) == 0) || nf_ct_match(ct, loser_ct)) { struct net *net = nf_ct_net(ct); + nf_conntrack_get(&ct->ct_general); + nf_ct_acct_merge(ct, ctinfo, loser_ct); nf_ct_add_to_dying_list(loser_ct); nf_conntrack_put(&loser_ct->ct_general); @@ -937,7 +937,6 @@ static int __nf_ct_resolve_clash(struct sk_buff *skb, return NF_ACCEPT; } - nf_ct_put(ct); return NF_DROP; } -- 2.20.1