Patch Detail
get:
Show a patch.
patch:
Update a patch.
put:
Update a patch.
GET /api/patches/812660/?format=api
{ "id": 812660, "url": "http://patchwork.ozlabs.org/api/patches/812660/?format=api", "web_url": "http://patchwork.ozlabs.org/project/netdev/patch/20170911233332.7594-2-xiyou.wangcong@gmail.com/", "project": { "id": 7, "url": "http://patchwork.ozlabs.org/api/projects/7/?format=api", "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": "<20170911233332.7594-2-xiyou.wangcong@gmail.com>", "list_archive_url": null, "date": "2017-09-11T23:33:30", "name": "[net,v3,1/3] net_sched: get rid of tcfa_rcu", "commit_ref": null, "pull_url": null, "state": "accepted", "archived": true, "hash": "88b17f24db4c95563a895e99c7440db908e6c7b2", "submitter": { "id": 211, "url": "http://patchwork.ozlabs.org/api/people/211/?format=api", "name": "Cong Wang", "email": "xiyou.wangcong@gmail.com" }, "delegate": { "id": 34, "url": "http://patchwork.ozlabs.org/api/users/34/?format=api", "username": "davem", "first_name": "David", "last_name": "Miller", "email": "davem@davemloft.net" }, "mbox": "http://patchwork.ozlabs.org/project/netdev/patch/20170911233332.7594-2-xiyou.wangcong@gmail.com/mbox/", "series": [ { "id": 2596, "url": "http://patchwork.ozlabs.org/api/series/2596/?format=api", "web_url": "http://patchwork.ozlabs.org/project/netdev/list/?series=2596", "date": "2017-09-11T23:33:29", "name": "net_sched: fix filter chain reference counting", "version": 3, "mbox": "http://patchwork.ozlabs.org/series/2596/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/812660/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/812660/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "<netdev-owner@vger.kernel.org>", "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; helo=vger.kernel.org;\n\tenvelope-from=netdev-owner@vger.kernel.org;\n\treceiver=<UNKNOWN>)", "ozlabs.org; dkim=pass (2048-bit key;\n\tunprotected) header.d=gmail.com header.i=@gmail.com\n\theader.b=\"mJ+ym3+I\"; dkim-atps=neutral" ], "Received": [ "from vger.kernel.org (vger.kernel.org [209.132.180.67])\n\tby ozlabs.org (Postfix) with ESMTP id 3xrklT241Hz9s8J\n\tfor <patchwork-incoming@ozlabs.org>;\n\tTue, 12 Sep 2017 09:33:57 +1000 (AEST)", "(majordomo@vger.kernel.org) by vger.kernel.org via listexpand\n\tid S1751144AbdIKXdy (ORCPT <rfc822;patchwork-incoming@ozlabs.org>);\n\tMon, 11 Sep 2017 19:33:54 -0400", "from mail-pf0-f193.google.com ([209.85.192.193]:33769 \"EHLO\n\tmail-pf0-f193.google.com\" rhost-flags-OK-OK-OK-OK) by vger.kernel.org\n\twith ESMTP id S1750957AbdIKXdw (ORCPT\n\t<rfc822;netdev@vger.kernel.org>); Mon, 11 Sep 2017 19:33:52 -0400", "by mail-pf0-f193.google.com with SMTP id h4so5522148pfk.0\n\tfor <netdev@vger.kernel.org>; Mon, 11 Sep 2017 16:33:52 -0700 (PDT)", "from tw-172-25-30-113.office.twttr.net ([8.25.197.25])\n\tby smtp.gmail.com with ESMTPSA id\n\tf5sm15676526pga.30.2017.09.11.16.33.50\n\t(version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256);\n\tMon, 11 Sep 2017 16:33:50 -0700 (PDT)" ], "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/relaxed;\n\td=gmail.com; s=20161025;\n\th=from:to:cc:subject:date:message-id:in-reply-to:references;\n\tbh=ATafWyJ6xXo4ACe+NKNF8mWfMPDnfEfp65HhvrrY1wE=;\n\tb=mJ+ym3+IeArB6rUU4PBV5MjGByiVWRkCRatvw1Nnr3XMFnPILK2MsXRmCGT3YscbCw\n\t5W86SpWlXBSTZlYTuOW/Qc633P3NNOpLSiLDD4lJrTyaekozB99ZCh+7WGPHlDPpV75o\n\tTXq9RyzBWQw7WNk2me09kz+PvP3uy7wubVjKfEFRqNjua0rd8eNzlP7iYiTFl883fuCY\n\toE6dfR+ZtLSHbvfIOVO6WI/JYedO+AO20IShO8auvqynNbf7Ubtou5zWpbau/BKQVDng\n\tvXXJnyqBRt2vdVOWexhnJbl3pAZ9Ch9YIqaKNiR13nQS+5Awh4sKk3e9R0AgeWL2GFd1\n\ttIWQ==", "X-Google-DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/relaxed;\n\td=1e100.net; s=20161025;\n\th=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to\n\t:references;\n\tbh=ATafWyJ6xXo4ACe+NKNF8mWfMPDnfEfp65HhvrrY1wE=;\n\tb=lgP5ymAG8UqwdQ6hioBCSoQBnjUs574JJpkMdeggFSDDj4RQxs8sHReYyblNtCf2Zy\n\tfUjbV3EcBSqiaO31ly1jox8+3VR4v5LMpAZcTMmISbQD3NXhoScxOADMxqd+ZUGwUco/\n\t7IBi30oI9fRGhVcVdiyy3pqvTR2pPY3x1KtQK9yj/IX/TR3Wu5LgyFFMfjMJGFUQlxzx\n\tCyr814ISGROzB8NkkdLk2FnUcDt3UMYJU7flcj7ON5YEn3HfrsLB+/qNd+kwMt6jflrX\n\tdgixuJg/YeJ6hE57SPhMkdm2jXjDW84w+2lWObcx3uovIExMstzmcMVBE+k0e9RLL15W\n\tXJYQ==", "X-Gm-Message-State": "AHPjjUhN3rVeeUDfyMzvhYOLHC5fUSKgN6XCrh5K19+xnrS/yTTd7kW0\n\tuxjSwNosERJ2+Or6r9E=", "X-Google-Smtp-Source": "ADKCNb7oAjgE3bk/d+I33xRu5J8nqTJkvvxx/VlmKnzjme7T9Qu2MTGPresHpTJRKD7J5sEg77G2DA==", "X-Received": "by 10.84.132.65 with SMTP id 59mr15522692ple.366.1505172831677; \n\tMon, 11 Sep 2017 16:33:51 -0700 (PDT)", "From": "Cong Wang <xiyou.wangcong@gmail.com>", "To": "netdev@vger.kernel.org", "Cc": "jiri@mellanox.com, jakub.kicinski@netronome.com, jhs@mojatatu.com,\n\tCong Wang <xiyou.wangcong@gmail.com>, Eric Dumazet <edumazet@google.com>", "Subject": "[Patch net v3 1/3] net_sched: get rid of tcfa_rcu", "Date": "Mon, 11 Sep 2017 16:33:30 -0700", "Message-Id": "<20170911233332.7594-2-xiyou.wangcong@gmail.com>", "X-Mailer": "git-send-email 2.9.4", "In-Reply-To": "<20170911233332.7594-1-xiyou.wangcong@gmail.com>", "References": "<20170911233332.7594-1-xiyou.wangcong@gmail.com>", "Sender": "netdev-owner@vger.kernel.org", "Precedence": "bulk", "List-ID": "<netdev.vger.kernel.org>", "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\nPlease see also the comments in code.\n\nCc: Jiri Pirko <jiri@mellanox.com>\nCc: Jamal Hadi Salim <jhs@mojatatu.com>\nCc: Eric Dumazet <edumazet@google.com>\nSigned-off-by: Cong Wang <xiyou.wangcong@gmail.com>\n---\n include/net/act_api.h | 2 --\n net/sched/act_api.c | 17 ++++++++---------\n 2 files changed, 8 insertions(+), 11 deletions(-)", "diff": "diff --git a/include/net/act_api.h b/include/net/act_api.h\nindex 8f3d5d8b5ae0..b944e0eb93be 100644\n--- a/include/net/act_api.h\n+++ b/include/net/act_api.h\n@@ -34,7 +34,6 @@ 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@@ -50,7 +49,6 @@ 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 /* Update lastuse only if needed, to avoid dirtying a cache line.\n * We use a temp variable to avoid fetching jiffies twice.\ndiff --git a/net/sched/act_api.c b/net/sched/act_api.c\nindex a306974e2fb4..fcd7dc7b807a 100644\n--- a/net/sched/act_api.c\n+++ b/net/sched/act_api.c\n@@ -53,10 +53,13 @@ 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+/* XXX: For standalone actions, we don't need a RCU grace period either, because\n+ * actions are always connected to filters and filters are already destroyed in\n+ * RCU callbacks, so after a RCU grace period actions are already disconnected\n+ * from filters. Readers later can not find us.\n+ */\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 +79,7 @@ static void tcf_idr_remove(struct tcf_idrinfo *idrinfo, struct tc_action *p)\n \tidr_remove_ext(&idrinfo->action_idr, p->tcfa_index);\n \tspin_unlock_bh(&idrinfo->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_idr_release(struct tc_action *p, bool bind, bool strict)\n@@ -259,7 +258,7 @@ void tcf_idr_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_idr_cleanup);\n \n", "prefixes": [ "net", "v3", "1/3" ] }