From d72b450666d8d0ee1dc01911c4193bc27b71af3d Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Sun, 13 Mar 2016 23:28:00 -0400 Subject: [PATCH] ipv4: Don't do expensive useless work during inetdev destroy. 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(-) diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index e41c40f48cfe..757bee7e8a9b 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -326,6 +326,9 @@ static void __inet_del_ifa(struct in_device *in_dev, struct in_ifaddr **ifap, 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_device *in_dev, struct in_ifaddr **ifap, fib_del_ifaddr(ifa, ifa1); } +no_promotions: /* 2. Unlink it */ *ifap = ifa1->ifa_next; diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c index 92fc5f69f5da..76784c7d54da 100644 --- a/net/ipv4/fib_frontend.c +++ b/net/ipv4/fib_frontend.c @@ -764,6 +764,9 @@ void fib_del_ifaddr(struct in_ifaddr *ifa, struct in_ifaddr *iprim) 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 *ifa, struct in_ifaddr *iprim) } } +no_promotions: if (!(ok & BRD_OK)) fib_magic(RTM_DELROUTE, RTN_BROADCAST, ifa->ifa_broadcast, 32, prim); if (subnet && ifa->ifa_prefixlen < 31) { diff --git a/net/ipv4/netfilter/ipt_MASQUERADE.c b/net/ipv4/netfilter/ipt_MASQUERADE.c index 9931152a78b5..9a30807c8c28 100644 --- a/net/ipv4/netfilter/ipt_MASQUERADE.c +++ b/net/ipv4/netfilter/ipt_MASQUERADE.c @@ -123,8 +123,16 @@ static int masq_inet_event(struct notifier_block *this, 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 = { -- 2.39.2