From patchwork Tue May 19 21:45:38 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Ahmed S. Darwish" X-Patchwork-Id: 218981 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=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 496BFC433E0 for ; Tue, 19 May 2020 21:48:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 208F0205CB for ; Tue, 19 May 2020 21:48:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728480AbgESVrl (ORCPT ); Tue, 19 May 2020 17:47:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40976 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728351AbgESVrf (ORCPT ); Tue, 19 May 2020 17:47:35 -0400 Received: from Galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5EB28C08C5C0; Tue, 19 May 2020 14:47:35 -0700 (PDT) Received: from [5.158.153.53] (helo=debian-buster-darwi.lab.linutronix.de.) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.80) (envelope-from ) id 1jbA4r-0002nf-QD; Tue, 19 May 2020 23:47:09 +0200 From: "Ahmed S. Darwish" To: Peter Zijlstra , Ingo Molnar , Will Deacon Cc: Thomas Gleixner , "Paul E. McKenney" , "Sebastian A. Siewior" , Steven Rostedt , LKML , "Ahmed S. Darwish" , Pablo Neira Ayuso , Jozsef Kadlecsik , Florian Westphal , "David S. Miller" , Jakub Kicinski , netfilter-devel@vger.kernel.org, coreteam@netfilter.org, netdev@vger.kernel.org Subject: [PATCH v1 16/25] netfilter: nft_set_rbtree: Use sequence counter with associated rwlock Date: Tue, 19 May 2020 23:45:38 +0200 Message-Id: <20200519214547.352050-17-a.darwish@linutronix.de> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200519214547.352050-1-a.darwish@linutronix.de> References: <20200519214547.352050-1-a.darwish@linutronix.de> MIME-Version: 1.0 X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1, SHORTCIRCUIT=-0.0001 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org A sequence counter write side critical section must be protected by some form of locking to serialize writers. A plain seqcount_t does not contain the information of which lock must be held when entering a write side critical section. Use the new seqcount_rwlock_t data type, which allows to associate a rwlock with the sequence counter. This enables lockdep to verify that the rwlock used for writer serialization is held when the write side critical section is entered. If lockdep is disabled this lock association is compiled out and has neither storage size nor runtime overhead. Signed-off-by: Ahmed S. Darwish --- net/netfilter/nft_set_rbtree.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/netfilter/nft_set_rbtree.c b/net/netfilter/nft_set_rbtree.c index 3ffef454d469..f50d986d43c5 100644 --- a/net/netfilter/nft_set_rbtree.c +++ b/net/netfilter/nft_set_rbtree.c @@ -18,7 +18,7 @@ struct nft_rbtree { struct rb_root root; rwlock_t lock; - seqcount_t count; + seqcount_rwlock_t count; struct delayed_work gc_work; }; @@ -505,7 +505,7 @@ static int nft_rbtree_init(const struct nft_set *set, struct nft_rbtree *priv = nft_set_priv(set); rwlock_init(&priv->lock); - seqcount_init(&priv->count); + seqcount_rwlock_init(&priv->count, &priv->lock); priv->root = RB_ROOT; INIT_DEFERRABLE_WORK(&priv->gc_work, nft_rbtree_gc);