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 B8EE8C433FE for ; Sun, 9 Oct 2022 22:30:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232016AbiJIWaS (ORCPT ); Sun, 9 Oct 2022 18:30:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35328 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231810AbiJIW00 (ORCPT ); Sun, 9 Oct 2022 18:26:26 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7B68F3E75B; Sun, 9 Oct 2022 15:18:40 -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 ams.source.kernel.org (Postfix) with ESMTPS id 95DE5B80DD2; Sun, 9 Oct 2022 22:18:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EFAD1C43470; Sun, 9 Oct 2022 22:18:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1665353883; bh=XwHKS7e8GthxQUR4oQfDVgwh4JKJsT8M94kHeLGQLys=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OtFqngI1+fPn1uWnuuQt8fM36PDDgtPm7J4bY7BJntdBT6O5usgzuDY84gWa0uB1x u+PIdyuJApjrL6NhUedfEIydngDgofwSgEgkTZOuE2p28diJuq8eXr6AnypIDPI925 BazziRb+21pOIAL5WzlJUZMcfKAY74z+9uz+bGwjccW+eJfUx/N60UAbmYpRotVm1y zXmfdqxoa1AKk4VmiekpUBfVR3WJEdNBkRgKZsOk2HBUXeZjRmReYlKhqIDrIXbiEh kiy5sTrDxLjbAyj54q32DE++rpCb1DVY/vfdg/RaOkOihsbMPzJNrvOE6WdzI+nh7X yd7BxO+dPvbyw== 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 5.19 52/73] net/sched: taprio: taprio_dump and taprio_change are protected by rtnl_mutex Date: Sun, 9 Oct 2022 18:14:30 -0400 Message-Id: <20221009221453.1216158-52-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221009221453.1216158-1-sashal@kernel.org> References: <20221009221453.1216158-1-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 86675a79da1e..71408136d4a0 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -1492,10 +1492,8 @@ 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)) @@ -1888,9 +1886,8 @@ 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)); @@ -1934,8 +1931,6 @@ 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: @@ -1945,7 +1940,6 @@ 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