Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754616AbcDZXUt (ORCPT ); Tue, 26 Apr 2016 19:20:49 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:40725 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754136AbcDZXUr (ORCPT ); Tue, 26 Apr 2016 19:20:47 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Cyrill Gorcunov" , "David S. Miller" , "Solar Designer" Date: Wed, 27 Apr 2016 01:02:24 +0200 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 083/115] ipv4: Don't do expensive useless work during inetdev destroy. In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8426:ae4:c500:9cba:69ae:962d:6167 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2879 Lines: 91 3.2.80-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: "David S. Miller" commit fbd40ea0180a2d328c5adc61414dc8bab9335ce2 upstream. When an inetdev is destroyed, every address assigned to the interface is removed. And in this scenerio we do two pointless things which can be very expensive if the number of assigned interfaces is large: 1) Address promotion. We are deleting all addresses, so there is no point in doing this. 2) A full nf conntrack table purge for every address. We only need to do this once, as is already caught by the existing masq_dev_notifier so masq_inet_event() can skip this. Reported-by: Solar Designer Signed-off-by: David S. Miller Tested-by: Cyrill Gorcunov [bwh: Backported to 3.2: adjust filename, context] Signed-off-by: Ben Hutchings --- net/ipv4/devinet.c | 4 ++++ net/ipv4/fib_frontend.c | 4 ++++ net/ipv4/netfilter/ipt_MASQUERADE.c | 12 ++++++++++-- 3 files changed, 18 insertions(+), 2 deletions(-) --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -326,6 +326,9 @@ static void __inet_del_ifa(struct in_dev ASSERT_RTNL(); + if (in_dev->dead) + goto no_promotions; + /* 1. Deleting primary ifaddr forces deletion all secondaries * unless alias promotion is set **/ @@ -372,6 +375,7 @@ static void __inet_del_ifa(struct in_dev fib_del_ifaddr(ifa, ifa1); } +no_promotions: /* 2. Unlink it */ *ifap = ifa1->ifa_next; --- a/net/ipv4/fib_frontend.c +++ b/net/ipv4/fib_frontend.c @@ -764,6 +764,9 @@ void fib_del_ifaddr(struct in_ifaddr *if subnet = 1; } + if (in_dev->dead) + goto no_promotions; + /* Deletion is more complicated than add. * We should take care of not to delete too much :-) * @@ -839,6 +842,7 @@ void fib_del_ifaddr(struct in_ifaddr *if } } +no_promotions: if (!(ok & BRD_OK)) fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim); if (subnet && ifa->ifa_prefixlen < 31) { --- a/net/ipv4/netfilter/ipt_MASQUERADE.c +++ b/net/ipv4/netfilter/ipt_MASQUERADE.c @@ -123,8 +123,16 @@ static int masq_inet_event(struct notifi unsigned long event, void *ptr) { - struct net_device *dev = ((struct in_ifaddr *)ptr)->ifa_dev->dev; - return masq_device_event(this, event, dev); + struct in_device *idev = ((struct in_ifaddr *)ptr)->ifa_dev; + /* The masq_dev_notifier will catch the case of the device going + * down. So if the inetdev is dead and being destroyed we have + * no work to do. Otherwise this is an individual address removal + * and we have to perform the flush. + */ + if (idev->dead) + return NOTIFY_DONE; + + return masq_device_event(this, event, idev->dev); } static struct notifier_block masq_dev_notifier = {