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authorEric Dumazet <edumazet@google.com>2012-08-22 17:19:46 +0000
committerDavid S. Miller <davem@davemloft.net>2012-08-22 21:50:36 -0700
commit0115e8e30d6fcdd4b8faa30d3ffd90859a591f51 (patch)
tree725026e2192e57b98366947ab53c73689ca040a8 /net/ipv4/devinet.c
parentbf277b0ccea7d2422b85e232017ce3fddbe9c49c (diff)
downloadlinux-stericsson-0115e8e30d6fcdd4b8faa30d3ffd90859a591f51.tar.gz
net: remove delay at device dismantle
I noticed extra one second delay in device dismantle, tracked down to a call to dst_dev_event() while some call_rcu() are still in RCU queues. These call_rcu() were posted by rt_free(struct rtable *rt) calls. We then wait a little (but one second) in netdev_wait_allrefs() before kicking again NETDEV_UNREGISTER. As the call_rcu() are now completed, dst_dev_event() can do the needed device swap on busy dst. To solve this problem, add a new NETDEV_UNREGISTER_FINAL, called after a rcu_barrier(), but outside of RTNL lock. Use NETDEV_UNREGISTER_FINAL with care ! Change dst_dev_event() handler to react to NETDEV_UNREGISTER_FINAL Also remove NETDEV_UNREGISTER_BATCH, as its not used anymore after IP cache removal. With help from Gao feng Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Cc: Mahesh Bandewar <maheshb@google.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Gao feng <gaofeng@cn.fujitsu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/devinet.c')
-rw-r--r--net/ipv4/devinet.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index adf273f8ad2e..6a5e6e4b142c 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1147,8 +1147,12 @@ static int inetdev_event(struct notifier_block *this, unsigned long event,
void *ptr)
{
struct net_device *dev = ptr;
- struct in_device *in_dev = __in_dev_get_rtnl(dev);
+ struct in_device *in_dev;
+ if (event == NETDEV_UNREGISTER_FINAL)
+ goto out;
+
+ in_dev = __in_dev_get_rtnl(dev);
ASSERT_RTNL();
if (!in_dev) {