From patchwork Mon Feb 4 12:32:47 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vlad Buslov X-Patchwork-Id: 1035860 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=mellanox.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 43tRvl5mBBz9s4Z for ; Mon, 4 Feb 2019 23:33:39 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730574AbfBDMdi (ORCPT ); Mon, 4 Feb 2019 07:33:38 -0500 Received: from mail-il-dmz.mellanox.com ([193.47.165.129]:57155 "EHLO mellanox.co.il" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728701AbfBDMdh (ORCPT ); Mon, 4 Feb 2019 07:33:37 -0500 Received: from Internal Mail-Server by MTLPINE1 (envelope-from vladbu@mellanox.com) with ESMTPS (AES256-SHA encrypted); 4 Feb 2019 14:33:31 +0200 Received: from reg-r-vrt-018-180.mtr.labs.mlnx. (reg-r-vrt-018-180.mtr.labs.mlnx [10.213.18.180]) by labmailer.mlnx (8.13.8/8.13.8) with ESMTP id x14CXVGG032317; Mon, 4 Feb 2019 14:33:31 +0200 From: Vlad Buslov To: netdev@vger.kernel.org Cc: jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us, davem@davemloft.net, ast@kernel.org, daniel@iogearbox.net, Vlad Buslov Subject: [PATCH net-next v3 02/16] net: sched: refactor tc_ctl_chain() to use block->lock Date: Mon, 4 Feb 2019 14:32:47 +0200 Message-Id: <20190204123301.4223-3-vladbu@mellanox.com> X-Mailer: git-send-email 2.13.6 In-Reply-To: <20190204123301.4223-1-vladbu@mellanox.com> References: <20190204123301.4223-1-vladbu@mellanox.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org In order to remove dependency on rtnl lock, modify chain API to use block->lock to protect chain from concurrent modification. Rearrange tc_ctl_chain() code to call tcf_chain_hold() while holding block->lock to prevent concurrent chain removal. Signed-off-by: Vlad Buslov Acked-by: Jiri Pirko --- net/sched/cls_api.c | 36 +++++++++++++++++++++++++----------- 1 file changed, 25 insertions(+), 11 deletions(-) diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index cc416b6a3aa2..a1bd1cd0e1ae 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -2247,6 +2247,8 @@ static int tc_ctl_chain(struct sk_buff *skb, struct nlmsghdr *n, err = -EINVAL; goto errout_block; } + + mutex_lock(&block->lock); chain = tcf_chain_lookup(block, chain_index); if (n->nlmsg_type == RTM_NEWCHAIN) { if (chain) { @@ -2258,41 +2260,49 @@ static int tc_ctl_chain(struct sk_buff *skb, struct nlmsghdr *n, } else { NL_SET_ERR_MSG(extack, "Filter chain already exists"); err = -EEXIST; - goto errout_block; + goto errout_block_locked; } } else { if (!(n->nlmsg_flags & NLM_F_CREATE)) { NL_SET_ERR_MSG(extack, "Need both RTM_NEWCHAIN and NLM_F_CREATE to create a new chain"); err = -ENOENT; - goto errout_block; + goto errout_block_locked; } chain = tcf_chain_create(block, chain_index); if (!chain) { NL_SET_ERR_MSG(extack, "Failed to create filter chain"); err = -ENOMEM; - goto errout_block; + goto errout_block_locked; } } } else { if (!chain || tcf_chain_held_by_acts_only(chain)) { NL_SET_ERR_MSG(extack, "Cannot find specified filter chain"); err = -EINVAL; - goto errout_block; + goto errout_block_locked; } tcf_chain_hold(chain); } + if (n->nlmsg_type == RTM_NEWCHAIN) { + /* Modifying chain requires holding parent block lock. In case + * the chain was successfully added, take a reference to the + * chain. This ensures that an empty chain does not disappear at + * the end of this function. + */ + tcf_chain_hold(chain); + chain->explicitly_created = true; + } + mutex_unlock(&block->lock); + switch (n->nlmsg_type) { case RTM_NEWCHAIN: err = tc_chain_tmplt_add(chain, net, tca, extack); - if (err) + if (err) { + tcf_chain_put_explicitly_created(chain); goto errout; - /* In case the chain was successfully added, take a reference - * to the chain. This ensures that an empty chain - * does not disappear at the end of this function. - */ - tcf_chain_hold(chain); - chain->explicitly_created = true; + } + tc_chain_notify(chain, NULL, 0, NLM_F_CREATE | NLM_F_EXCL, RTM_NEWCHAIN, false); break; @@ -2327,6 +2337,10 @@ static int tc_ctl_chain(struct sk_buff *skb, struct nlmsghdr *n, /* Replay the request. */ goto replay; return err; + +errout_block_locked: + mutex_unlock(&block->lock); + goto errout_block; } /* called with RTNL */