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 1024AC4332F for ; Sun, 9 Oct 2022 22:42:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232968AbiJIWmh (ORCPT ); Sun, 9 Oct 2022 18:42:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58806 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233040AbiJIWk1 (ORCPT ); Sun, 9 Oct 2022 18:40:27 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 73AB041D07; Sun, 9 Oct 2022 15:21:58 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 311B360C2A; Sun, 9 Oct 2022 22:20:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 55398C43470; Sun, 9 Oct 2022 22:20:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1665354051; bh=Svku7iPweTfGQwgBqouCE3/CF9p7StAi3Qh/c7ijZ5Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RX3GFz7VjxvoYlPzfrPCbuEgBSB04iqtnGevpEkbES4JJbxfW8r2aH34aQ13kg1Ly vc3EpzuN4PWSYJQFWf6AbKMy576TnQE5pOmJyB9N8kjOpvdpyBsWrtoB0rA8KKze5c CRqv5q7ZnuPq9k86jWfOsiLxkUXD2pIeAevtloZaLEJwV82jJk/4BlTRqj43j9mz3K Wruramz9gS1ccyyDdWk0nBhzhPaRYb7tXImYHNBW9jo/wv3Q/nztLK1jJml1itU5HL N1gYBVQCV8KEEVAp1y0eG/Z96a8eyy4R6iChVbXPuX/EGjUvpVqW2Nc4DSP7Pb1BzF p/lirsSamnMyQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Vladimir Oltean , Jakub Kicinski , Sasha Levin , vinicius.gomes@intel.com, jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 5.15 33/46] net/sched: taprio: taprio_dump and taprio_change are protected by rtnl_mutex Date: Sun, 9 Oct 2022 18:18:58 -0400 Message-Id: <20221009221912.1217372-33-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221009221912.1217372-1-sashal@kernel.org> References: <20221009221912.1217372-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Vladimir Oltean [ Upstream commit 18cdd2f0998a4967b1fff4c43ed9aef049e42c39 ] Since the writer-side lock is taken here, we do not need to open an RCU read-side critical section, instead we can use rtnl_dereference() to tell lockdep we are serialized with concurrent writes. Signed-off-by: Vladimir Oltean Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/sched/sch_taprio.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c index ae7ca68f2cf9..0ac3fbc13b7e 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -1491,10 +1491,8 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt, } INIT_LIST_HEAD(&new_admin->entries); - rcu_read_lock(); - oper = rcu_dereference(q->oper_sched); - admin = rcu_dereference(q->admin_sched); - rcu_read_unlock(); + oper = rtnl_dereference(q->oper_sched); + admin = rtnl_dereference(q->admin_sched); /* no changes - no new mqprio settings */ if (!taprio_mqprio_cmp(dev, mqprio)) @@ -1887,9 +1885,8 @@ static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb) struct nlattr *nest, *sched_nest; unsigned int i; - rcu_read_lock(); - oper = rcu_dereference(q->oper_sched); - admin = rcu_dereference(q->admin_sched); + oper = rtnl_dereference(q->oper_sched); + admin = rtnl_dereference(q->admin_sched); opt.num_tc = netdev_get_num_tc(dev); memcpy(opt.prio_tc_map, dev->prio_tc_map, sizeof(opt.prio_tc_map)); @@ -1933,8 +1930,6 @@ static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb) nla_nest_end(skb, sched_nest); done: - rcu_read_unlock(); - return nla_nest_end(skb, nest); admin_error: @@ -1944,7 +1939,6 @@ static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb) nla_nest_cancel(skb, nest); start_error: - rcu_read_unlock(); return -ENOSPC; } -- 2.35.1