From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-3366930-1521215571-2-6129190673391420017 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1521215570; b=T8t1pwkuV0MDsWw3pr+npY4/G9PnAjIJlFnQGBIMaNoRpEx 1sQSrxscSOTIK4DkPzl5yLPX+CfD1xOOpkOe0NqJIuHQzGT3QzmJVdlgEuq/Kx4b UgaBoMPYH4EHO6c2iL0E8nXOeKl6TPhESmNmqgqwYwmni4z6anPbROjhGskKaz08 6Ch8wijd4fn5uC1K2rP7x2u+nWaExfZfd7gx27d1vg+ictqzcx6HrCZ02fj6nHTv tTadAWif6cG/PB7teJLW9sKgeCb6wSp0W2E5JlVGqtV5ldc3Vj1bEWmh28B29XVC IZ4y+U44D1WicalXaprtMHxR5WEKOcWH2fTkkWw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-type:sender :list-id; s=arctest; t=1521215570; bh=L9Hv6b8n9f6uHoOfm88dD2vUtO lFOrtDnWEqbG72cig=; b=nXwyTn2+JczFNXLOzW40M0AetteM/Fd6M/1MCTrYy4 pTLbLpQseGuu7eGrBPYypCXUjr+Bx5hG/vuzn9CPCbY/JMybO8lFpiXFPqdctQgt 3npQnNLp7cJ3Zs0fMfQVa7+yk41BFcudn8+FgIuJvxHslx0a/uTp3s1EEaZ7Spi9 jptluvxATLVeD1uXYsByxklrsKylZJ3gGlftB/MJ+HIeZhLInXD9pfA5XBNe0S/x ArYB6D1kJ+JI8J9WgJkLq1ODsksNOODLWS8ne5PkoKJEsm/ONKCXfjodzg0DE+TO WdNr8wt4cxt3fcvEx5yLCAgCNHO2AvTcYp+jvMR+ONpg== ARC-Authentication-Results: i=1; mx6.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-category=clean score=-100 state=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes Authentication-Results: mx6.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-category=clean score=-100 state=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965389AbeCPPoR (ORCPT ); Fri, 16 Mar 2018 11:44:17 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:45864 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965372AbeCPPoL (ORCPT ); Fri, 16 Mar 2018 11:44:11 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, John Fastabend , "David S. Miller" , Sasha Levin Subject: [PATCH 4.15 109/128] net: sched: drop qdisc_reset from dev_graft_qdisc Date: Fri, 16 Mar 2018 16:24:10 +0100 Message-Id: <20180316152341.971330169@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180316152336.199007505@linuxfoundation.org> References: <20180316152336.199007505@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: John Fastabend [ Upstream commit 7bbde83b1860c28a1cc35516352c4e7e5172c29a ] In qdisc_graft_qdisc a "new" qdisc is attached and the 'qdisc_destroy' operation is called on the old qdisc. The destroy operation will wait a rcu grace period and call qdisc_rcu_free(). At which point gso_cpu_skb is free'd along with all stats so no need to zero stats and gso_cpu_skb from the graft operation itself. Further after dropping the qdisc locks we can not continue to call qdisc_reset before waiting an rcu grace period so that the qdisc is detached from all cpus. By removing the qdisc_reset() here we get the correct property of waiting an rcu grace period and letting the qdisc_destroy operation clean up the qdisc correctly. Note, a refcnt greater than 1 would cause the destroy operation to be aborted however if this ever happened the reference to the qdisc would be lost and we would have a memory leak. Signed-off-by: John Fastabend Signed-off-by: David S. Miller Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- net/sched/sch_generic.c | 28 +++++++++++++++++++--------- 1 file changed, 19 insertions(+), 9 deletions(-) --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -762,10 +762,6 @@ struct Qdisc *dev_graft_qdisc(struct net root_lock = qdisc_lock(oqdisc); spin_lock_bh(root_lock); - /* Prune old scheduler */ - if (oqdisc && refcount_read(&oqdisc->refcnt) <= 1) - qdisc_reset(oqdisc); - /* ... and graft new one */ if (qdisc == NULL) qdisc = &noop_qdisc; @@ -916,6 +912,16 @@ static bool some_qdisc_is_busy(struct ne return false; } +static void dev_qdisc_reset(struct net_device *dev, + struct netdev_queue *dev_queue, + void *none) +{ + struct Qdisc *qdisc = dev_queue->qdisc_sleeping; + + if (qdisc) + qdisc_reset(qdisc); +} + /** * dev_deactivate_many - deactivate transmissions on several devices * @head: list of devices to deactivate @@ -926,7 +932,6 @@ static bool some_qdisc_is_busy(struct ne void dev_deactivate_many(struct list_head *head) { struct net_device *dev; - bool sync_needed = false; list_for_each_entry(dev, head, close_list) { netdev_for_each_tx_queue(dev, dev_deactivate_queue, @@ -936,20 +941,25 @@ void dev_deactivate_many(struct list_hea &noop_qdisc); dev_watchdog_down(dev); - sync_needed |= !dev->dismantle; } /* Wait for outstanding qdisc-less dev_queue_xmit calls. * This is avoided if all devices are in dismantle phase : * Caller will call synchronize_net() for us */ - if (sync_needed) - synchronize_net(); + synchronize_net(); /* Wait for outstanding qdisc_run calls. */ - list_for_each_entry(dev, head, close_list) + list_for_each_entry(dev, head, close_list) { while (some_qdisc_is_busy(dev)) yield(); + /* The new qdisc is assigned at this point so we can safely + * unwind stale skb lists and qdisc statistics + */ + netdev_for_each_tx_queue(dev, dev_qdisc_reset, NULL); + if (dev_ingress_queue(dev)) + dev_qdisc_reset(dev, dev_ingress_queue(dev), NULL); + } } void dev_deactivate(struct net_device *dev)