[PATCH 10/10] nf_conntrack: Use rcu_barrier().

Jesper Dangaard Brouer
2009-06-23T15:31:25Z

I'm not sure which is are most optimal place to call rcu_barrier().
The patch probably calls rcu_barrier() too much, but its a better
safe than sorry approach.

There is embedded some comments that I would like Patrick McHardy
to look at.

Signed-off-by: Jesper Dangaard Brouer <hawk@comx.dk>
---

net/netfilter/nf_conntrack_core.c | 5 +++++
net/netfilter/nf_conntrack_standalone.c | 2 ++
2 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 5f72b94..cea4537 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -1084,6 +1084,8 @@ static void nf_conntrack_cleanup_init_net(void)
{
nf_conntrack_helper_fini();
nf_conntrack_proto_fini();
+ rcu_barrier();
+ /* Need to wait for call_rcu() before dealloc the kmem_cache */
kmem_cache_destroy(nf_conntrack_cachep);
}

@@ -1118,6 +1120,9 @@ void nf_conntrack_cleanup(struct net *net)
/* This makes sure all current packets have passed through
netfilter framework. Roll on, two-stage module
delete... */
+ /* hawk@comx.dk 2009-06-20: Think this should be replaced by a
+ rcu_barrier() ???
+ */
synchronize_net();

nf_conntrack_cleanup_net(net);
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index 1935153..29c6cd0 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -500,6 +500,8 @@ static void nf_conntrack_net_exit(struct net *net)
nf_conntrack_standalone_fini_sysctl(net);
nf_conntrack_standalone_fini_proc(net);
nf_conntrack_cleanup(net);
+ /* hawk@comx.dk: Think rcu_barrier() should to be called earlier? */
+ rcu_barrier(); /* Wait for completion of call_rcu()'s */
}

static struct pernet_operations nf_conntrack_net_ops = {