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 X-Spam-Level: X-Spam-Status: No, score=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 59139C3A5A4 for ; Fri, 23 Aug 2019 18:51:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3BBAD21874 for ; Fri, 23 Aug 2019 18:51:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406008AbfHWSv1 (ORCPT ); Fri, 23 Aug 2019 14:51:27 -0400 Received: from mail-il-dmz.mellanox.com ([193.47.165.129]:44542 "EHLO mellanox.co.il" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2390833AbfHWSv0 (ORCPT ); Fri, 23 Aug 2019 14:51:26 -0400 Received: from Internal Mail-Server by MTLPINE1 (envelope-from vladbu@mellanox.com) with ESMTPS (AES256-SHA encrypted); 23 Aug 2019 21:51:19 +0300 Received: from reg-r-vrt-018-180.mtr.labs.mlnx. (reg-r-vrt-018-180.mtr.labs.mlnx [10.215.1.1]) by labmailer.mlnx (8.13.8/8.13.8) with ESMTP id x7NIpJEC012807; Fri, 23 Aug 2019 21:51:19 +0300 From: Vlad Buslov To: netdev@vger.kernel.org Cc: jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us, davem@davemloft.net, jakub.kicinski@netronome.com, pablo@netfilter.org, Vlad Buslov Subject: [PATCH net-next v2 01/10] net: sched: protect block offload-related fields with rw_semaphore Date: Fri, 23 Aug 2019 21:50:47 +0300 Message-Id: <20190823185056.12536-2-vladbu@mellanox.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190823185056.12536-1-vladbu@mellanox.com> References: <20190823185056.12536-1-vladbu@mellanox.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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, extend tcf_block with 'cb_lock' rwsem and use it to protect flow_block->cb_list and related counters from concurrent modification. The lock is taken in read mode for read-only traversal of cb_list in tc_setup_cb_call() and write mode in all other cases. This approach ensures that: - cb_list is not changed concurrently while filters is being offloaded on block. - block->nooffloaddevcnt is checked while holding the lock in read mode, but is only changed by bind/unbind code when holding the cb_lock in write mode to prevent concurrent modification. Signed-off-by: Vlad Buslov --- Changes from V1 to V2: - Rename 'errout' label to 'err_unlock'. include/net/sch_generic.h | 2 ++ net/sched/cls_api.c | 45 +++++++++++++++++++++++++++++++-------- 2 files changed, 38 insertions(+), 9 deletions(-) diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h index d9f359af0b93..a3eaf5f9d28f 100644 --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -13,6 +13,7 @@ #include #include #include +#include #include #include #include @@ -396,6 +397,7 @@ struct tcf_block { refcount_t refcnt; struct net *net; struct Qdisc *q; + struct rw_semaphore cb_lock; /* protects cb_list and offload counters */ struct flow_block flow_block; struct list_head owner_list; bool keep_dst; diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index e0d8b456e9f5..959b7ca1ca02 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -568,9 +568,11 @@ static void tc_indr_block_ing_cmd(struct net_device *dev, bo.block = &block->flow_block; + down_write(&block->cb_lock); cb(dev, cb_priv, TC_SETUP_BLOCK, &bo); tcf_block_setup(block, &bo); + up_write(&block->cb_lock); } static struct tcf_block *tc_dev_ingress_block(struct net_device *dev) @@ -661,6 +663,7 @@ static int tcf_block_offload_bind(struct tcf_block *block, struct Qdisc *q, struct net_device *dev = q->dev_queue->dev; int err; + down_write(&block->cb_lock); if (!dev->netdev_ops->ndo_setup_tc) goto no_offload_dev_inc; @@ -669,24 +672,31 @@ static int tcf_block_offload_bind(struct tcf_block *block, struct Qdisc *q, */ if (!tc_can_offload(dev) && tcf_block_offload_in_use(block)) { NL_SET_ERR_MSG(extack, "Bind to offloaded block failed as dev has offload disabled"); - return -EOPNOTSUPP; + err = -EOPNOTSUPP; + goto err_unlock; } err = tcf_block_offload_cmd(block, dev, ei, FLOW_BLOCK_BIND, extack); if (err == -EOPNOTSUPP) goto no_offload_dev_inc; if (err) - return err; + goto err_unlock; tc_indr_block_call(block, dev, ei, FLOW_BLOCK_BIND, extack); + up_write(&block->cb_lock); return 0; no_offload_dev_inc: - if (tcf_block_offload_in_use(block)) - return -EOPNOTSUPP; + if (tcf_block_offload_in_use(block)) { + err = -EOPNOTSUPP; + goto err_unlock; + } + err = 0; block->nooffloaddevcnt++; tc_indr_block_call(block, dev, ei, FLOW_BLOCK_BIND, extack); - return 0; +err_unlock: + up_write(&block->cb_lock); + return err; } static void tcf_block_offload_unbind(struct tcf_block *block, struct Qdisc *q, @@ -695,6 +705,7 @@ static void tcf_block_offload_unbind(struct tcf_block *block, struct Qdisc *q, struct net_device *dev = q->dev_queue->dev; int err; + down_write(&block->cb_lock); tc_indr_block_call(block, dev, ei, FLOW_BLOCK_UNBIND, NULL); if (!dev->netdev_ops->ndo_setup_tc) @@ -702,10 +713,12 @@ static void tcf_block_offload_unbind(struct tcf_block *block, struct Qdisc *q, err = tcf_block_offload_cmd(block, dev, ei, FLOW_BLOCK_UNBIND, NULL); if (err == -EOPNOTSUPP) goto no_offload_dev_dec; + up_write(&block->cb_lock); return; no_offload_dev_dec: WARN_ON(block->nooffloaddevcnt-- == 0); + up_write(&block->cb_lock); } static int @@ -820,6 +833,7 @@ static struct tcf_block *tcf_block_create(struct net *net, struct Qdisc *q, return ERR_PTR(-ENOMEM); } mutex_init(&block->lock); + init_rwsem(&block->cb_lock); flow_block_init(&block->flow_block); INIT_LIST_HEAD(&block->chain_list); INIT_LIST_HEAD(&block->owner_list); @@ -1355,6 +1369,8 @@ tcf_block_playback_offloads(struct tcf_block *block, flow_setup_cb_t *cb, struct tcf_proto *tp, *tp_prev; int err; + lockdep_assert_held(&block->cb_lock); + for (chain = __tcf_get_next_chain(block, NULL); chain; chain_prev = chain, @@ -1393,6 +1409,8 @@ static int tcf_block_bind(struct tcf_block *block, struct flow_block_cb *block_cb, *next; int err, i = 0; + lockdep_assert_held(&block->cb_lock); + list_for_each_entry(block_cb, &bo->cb_list, list) { err = tcf_block_playback_offloads(block, block_cb->cb, block_cb->cb_priv, true, @@ -1427,6 +1445,8 @@ static void tcf_block_unbind(struct tcf_block *block, { struct flow_block_cb *block_cb, *next; + lockdep_assert_held(&block->cb_lock); + list_for_each_entry_safe(block_cb, next, &bo->cb_list, list) { tcf_block_playback_offloads(block, block_cb->cb, block_cb->cb_priv, false, @@ -2987,19 +3007,26 @@ int tc_setup_cb_call(struct tcf_block *block, enum tc_setup_type type, int ok_count = 0; int err; + down_read(&block->cb_lock); /* Make sure all netdevs sharing this block are offload-capable. */ - if (block->nooffloaddevcnt && err_stop) - return -EOPNOTSUPP; + if (block->nooffloaddevcnt && err_stop) { + ok_count = -EOPNOTSUPP; + goto err_unlock; + } list_for_each_entry(block_cb, &block->flow_block.cb_list, list) { err = block_cb->cb(type, type_data, block_cb->cb_priv); if (err) { - if (err_stop) - return err; + if (err_stop) { + ok_count = err; + goto err_unlock; + } } else { ok_count++; } } +err_unlock: + up_read(&block->cb_lock); return ok_count; } EXPORT_SYMBOL(tc_setup_cb_call); -- 2.21.0