ipv4: Don't do expensive useless work during inetdev destroy.

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 <solar@openwall.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Tested-by: Cyrill Gorcunov <gorcunov@openvz.org>

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 65e76a48382c6e212fe42135f59f3636eba5ea4a..e333bc86bd39d8baf08ea336f20f99cc51ec945f 100644 (file)
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -334,6 +334,9 @@ 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
         **/
@@ -380,6 +383,7 @@ 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 47344759306011b5bb940e9cab9237b9e9f624b4..21add552e56a2dcb2f5b5737ccc946e431c39de5 100644 (file)
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -922,6 +922,9 @@ 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 :-)
         *
@@ -997,6 +1000,7 @@ 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/nf_nat_masquerade_ipv4.c b/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c
index c6eb42100e9a7d78a6a5c27434e42e3282b3af74..ea91058b5f6f4245a84179f81a8641756f60efff 100644 (file)
--- a/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c
+++ b/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c
@@ -108,10 +108,18 @@ 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;
+       struct in_device *idev = ((struct in_ifaddr *)ptr)->ifa_dev;
        struct netdev_notifier_info info;
 
-       netdev_notifier_info_init(&info, 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;
+
+       netdev_notifier_info_init(&info, idev->dev);
        return masq_device_event(this, event, &info);
 }