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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BDD4DC61D92 for ; Tue, 21 Nov 2023 12:13:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234704AbjKUMN4 (ORCPT ); Tue, 21 Nov 2023 07:13:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36034 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234690AbjKUMNz (ORCPT ); Tue, 21 Nov 2023 07:13:55 -0500 Received: from mail.netfilter.org (mail.netfilter.org [217.70.188.207]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id B2C0D138; Tue, 21 Nov 2023 04:13:51 -0800 (PST) From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: gregkh@linuxfoundation.org, sashal@kernel.org, stable@vger.kernel.org Subject: [PATCH -stable,5.4 18/26] netfilter: nft_set_rbtree: use read spinlock to avoid datapath contention Date: Tue, 21 Nov 2023 13:13:25 +0100 Message-Id: <20231121121333.294238-19-pablo@netfilter.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20231121121333.294238-1-pablo@netfilter.org> References: <20231121121333.294238-1-pablo@netfilter.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org commit 96b33300fba880ec0eafcf3d82486f3463b4b6da upstream. rbtree GC does not modify the datastructure, instead it collects expired elements and it enqueues a GC transaction. Use a read spinlock instead to avoid data contention while GC worker is running. Fixes: f6c383b8c31a ("netfilter: nf_tables: adapt set backend to use GC transaction API") Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nft_set_rbtree.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/net/netfilter/nft_set_rbtree.c b/net/netfilter/nft_set_rbtree.c index 4a8f2b6f7409..d9c436fa91b5 100644 --- a/net/netfilter/nft_set_rbtree.c +++ b/net/netfilter/nft_set_rbtree.c @@ -626,8 +626,7 @@ static void nft_rbtree_gc(struct work_struct *work) if (!gc) goto done; - write_lock_bh(&priv->lock); - write_seqcount_begin(&priv->count); + read_lock_bh(&priv->lock); for (node = rb_first(&priv->root); node != NULL; node = rb_next(node)) { /* Ruleset has been updated, try later. */ @@ -676,8 +675,7 @@ static void nft_rbtree_gc(struct work_struct *work) } try_later: - write_seqcount_end(&priv->count); - write_unlock_bh(&priv->lock); + read_unlock_bh(&priv->lock); if (gc) nft_trans_gc_queue_async_done(gc); -- 2.30.2