{"id":810845,"url":"http://patchwork.ozlabs.org/api/patches/810845/?format=json","web_url":"http://patchwork.ozlabs.org/project/netdev/patch/20170907042607.24413-1-xiyou.wangcong@gmail.com/","project":{"id":7,"url":"http://patchwork.ozlabs.org/api/projects/7/?format=json","name":"Linux network development","link_name":"netdev","list_id":"netdev.vger.kernel.org","list_email":"netdev@vger.kernel.org","web_url":null,"scm_url":null,"webscm_url":null,"list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20170907042607.24413-1-xiyou.wangcong@gmail.com>","list_archive_url":null,"date":"2017-09-07T04:26:06","name":"[net,v2,1/2] net_sched: get rid of tcfa_rcu","commit_ref":null,"pull_url":null,"state":"changes-requested","archived":true,"hash":"b4f393bef63236d5fe0112e16209cab3cbbf2972","submitter":{"id":211,"url":"http://patchwork.ozlabs.org/api/people/211/?format=json","name":"Cong Wang","email":"xiyou.wangcong@gmail.com"},"delegate":{"id":34,"url":"http://patchwork.ozlabs.org/api/users/34/?format=json","username":"davem","first_name":"David","last_name":"Miller","email":"davem@davemloft.net"},"mbox":"http://patchwork.ozlabs.org/project/netdev/patch/20170907042607.24413-1-xiyou.wangcong@gmail.com/mbox/","series":[{"id":1909,"url":"http://patchwork.ozlabs.org/api/series/1909/?format=json","web_url":"http://patchwork.ozlabs.org/project/netdev/list/?series=1909","date":"2017-09-07T04:26:06","name":"[net,v2,1/2] net_sched: get rid of tcfa_rcu","version":2,"mbox":"http://patchwork.ozlabs.org/series/1909/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/810845/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/810845/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":"patchwork-incoming@ozlabs.org","Delivered-To":"patchwork-incoming@ozlabs.org","Authentication-Results":["ozlabs.org;\n\tspf=none (mailfrom) smtp.mailfrom=vger.kernel.org\n\t(client-ip=209.132.180.67; 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\n\tWed, 06 Sep 2017 21:26:16 -0700 (PDT)","From":"Cong Wang ","To":"netdev@vger.kernel.org","Cc":"jakub.kicinski@netronome.com, Cong Wang ,\n\tJiri Pirko , Eric Dumazet ","Subject":"[Patch net v2 1/2] net_sched: get rid of tcfa_rcu","Date":"Wed, 6 Sep 2017 21:26:06 -0700","Message-Id":"<20170907042607.24413-1-xiyou.wangcong@gmail.com>","X-Mailer":"git-send-email 2.9.4","Sender":"netdev-owner@vger.kernel.org","Precedence":"bulk","List-ID":"","X-Mailing-List":"netdev@vger.kernel.org"},"content":"gen estimator has been rewritten in commit 1c0d32fde5bd\n(\"net_sched: gen_estimator: complete rewrite of rate estimators\"),\nthe caller is no longer needed to wait for a grace period.\nSo this patch gets rid of it.\n\nThis also completely closes a race condition between action free\npath and filter chain add/remove path for the following patch.\nBecause otherwise the nested RCU callback can't be caught by\nrcu_barrier().\n\nCc: Jiri Pirko \nCc: Eric Dumazet \nSigned-off-by: Cong Wang \n---\n include/net/act_api.h | 2 --\n net/sched/act_api.c | 12 +++---------\n 2 files changed, 3 insertions(+), 11 deletions(-)","diff":"diff --git a/include/net/act_api.h b/include/net/act_api.h\nindex 26ffd8333f50..68218a5f8e72 100644\n--- a/include/net/act_api.h\n+++ b/include/net/act_api.h\n@@ -38,7 +38,6 @@ struct tc_action {\n \tstruct gnet_stats_queue\t\ttcfa_qstats;\n \tstruct net_rate_estimator __rcu *tcfa_rate_est;\n \tspinlock_t\t\t\ttcfa_lock;\n-\tstruct rcu_head\t\t\ttcfa_rcu;\n \tstruct gnet_stats_basic_cpu __percpu *cpu_bstats;\n \tstruct gnet_stats_queue __percpu *cpu_qstats;\n \tstruct tc_cookie\t*act_cookie;\n@@ -55,7 +54,6 @@ struct tc_action {\n #define tcf_qstats\tcommon.tcfa_qstats\n #define tcf_rate_est\tcommon.tcfa_rate_est\n #define tcf_lock\tcommon.tcfa_lock\n-#define tcf_rcu\t\tcommon.tcfa_rcu\n \n static inline unsigned int tcf_hash(u32 index, unsigned int hmask)\n {\ndiff --git a/net/sched/act_api.c b/net/sched/act_api.c\nindex f2e9ed34a963..fc17d286a6a2 100644\n--- a/net/sched/act_api.c\n+++ b/net/sched/act_api.c\n@@ -53,10 +53,8 @@ static void tcf_action_goto_chain_exec(const struct tc_action *a,\n \tres->goto_tp = rcu_dereference_bh(chain->filter_chain);\n }\n \n-static void free_tcf(struct rcu_head *head)\n+static void free_tcf(struct tc_action *p)\n {\n-\tstruct tc_action *p = container_of(head, struct tc_action, tcfa_rcu);\n-\n \tfree_percpu(p->cpu_bstats);\n \tfree_percpu(p->cpu_qstats);\n \n@@ -76,11 +74,7 @@ static void tcf_hash_destroy(struct tcf_hashinfo *hinfo, struct tc_action *p)\n \thlist_del(&p->tcfa_head);\n \tspin_unlock_bh(&hinfo->lock);\n \tgen_kill_estimator(&p->tcfa_rate_est);\n-\t/*\n-\t * gen_estimator est_timer() might access p->tcfa_lock\n-\t * or bstats, wait a RCU grace period before freeing p\n-\t */\n-\tcall_rcu(&p->tcfa_rcu, free_tcf);\n+\tfree_tcf(p);\n }\n \n int __tcf_hash_release(struct tc_action *p, bool bind, bool strict)\n@@ -271,7 +265,7 @@ void tcf_hash_cleanup(struct tc_action *a, struct nlattr *est)\n {\n \tif (est)\n \t\tgen_kill_estimator(&a->tcfa_rate_est);\n-\tcall_rcu(&a->tcfa_rcu, free_tcf);\n+\tfree_tcf(a);\n }\n EXPORT_SYMBOL(tcf_hash_cleanup);\n \n","prefixes":["net","v2","1/2"]}