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| author |   Eric Dumazet <edumazet@google.com> | 2012-08-22 17:19:46 +0000 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2012-08-22 21:50:36 -0700 |
| commit | 0115e8e30d6fcdd4b8faa30d3ffd90859a591f51 (patch) | |
| tree | 725026e2192e57b98366947ab53c73689ca040a8 /net/ipv4/devinet.c | |
| parent | Merge git://1984.lsi.us.es/nf-next (diff) | |
| download | linux-dev-0115e8e30d6fcdd4b8faa30d3ffd90859a591f51.tar.xz linux-dev-0115e8e30d6fcdd4b8faa30d3ffd90859a591f51.zip | |
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.c | 6 |
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) { |