diff options
author | Pablo Neira Ayuso <pablo@netfilter.org> | 2009-06-03 12:32:06 +0400 |
---|---|---|
committer | pablo <pablo@1984.(none)> | 2009-06-03 12:32:06 +0400 |
commit | e34d5c1a4f9919a81b4ea4591d7383245f35cb8e (patch) | |
tree | 0a19bfe3e162b2b8de9b9414dcc2bef0a07e7133 /net/netfilter/nf_conntrack_ecache.c | |
parent | 17e6e4eac070607a35464ea7e2c5eceac32e5eca (diff) | |
download | linux-e34d5c1a4f9919a81b4ea4591d7383245f35cb8e.tar.xz |
netfilter: conntrack: replace notify chain by function pointer
This patch removes the notify chain infrastructure and replace it
by a simple function pointer. This issue has been mentioned in the
mailing list several times: the use of the notify chain adds
too much overhead for something that is only used by ctnetlink.
This patch also changes nfnetlink_send(). It seems that gfp_any()
returns GFP_KERNEL for user-context request, like those via
ctnetlink, inside the RCU read-side section which is not valid.
Using GFP_KERNEL is also evil since netlink may schedule(),
this leads to "scheduling while atomic" bug reports.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/netfilter/nf_conntrack_ecache.c')
-rw-r--r-- | net/netfilter/nf_conntrack_ecache.c | 83 |
1 files changed, 67 insertions, 16 deletions
diff --git a/net/netfilter/nf_conntrack_ecache.c b/net/netfilter/nf_conntrack_ecache.c index dee4190209cc..5516b3e64b43 100644 --- a/net/netfilter/nf_conntrack_ecache.c +++ b/net/netfilter/nf_conntrack_ecache.c @@ -16,24 +16,32 @@ #include <linux/stddef.h> #include <linux/err.h> #include <linux/percpu.h> -#include <linux/notifier.h> #include <linux/kernel.h> #include <linux/netdevice.h> #include <net/netfilter/nf_conntrack.h> #include <net/netfilter/nf_conntrack_core.h> -ATOMIC_NOTIFIER_HEAD(nf_conntrack_chain); -EXPORT_SYMBOL_GPL(nf_conntrack_chain); +static DEFINE_MUTEX(nf_ct_ecache_mutex); -ATOMIC_NOTIFIER_HEAD(nf_ct_expect_chain); -EXPORT_SYMBOL_GPL(nf_ct_expect_chain); +struct nf_ct_event_notifier *nf_conntrack_event_cb __read_mostly; +EXPORT_SYMBOL_GPL(nf_conntrack_event_cb); + +struct nf_exp_event_notifier *nf_expect_event_cb __read_mostly; +EXPORT_SYMBOL_GPL(nf_expect_event_cb); /* deliver cached events and clear cache entry - must be called with locally * disabled softirqs */ static inline void __nf_ct_deliver_cached_events(struct nf_conntrack_ecache *ecache) { + struct nf_ct_event_notifier *notify; + + rcu_read_lock(); + notify = rcu_dereference(nf_conntrack_event_cb); + if (notify == NULL) + goto out_unlock; + if (nf_ct_is_confirmed(ecache->ct) && !nf_ct_is_dying(ecache->ct) && ecache->events) { struct nf_ct_event item = { @@ -42,14 +50,15 @@ __nf_ct_deliver_cached_events(struct nf_conntrack_ecache *ecache) .report = 0 }; - atomic_notifier_call_chain(&nf_conntrack_chain, - ecache->events, - &item); + notify->fcn(ecache->events, &item); } ecache->events = 0; nf_ct_put(ecache->ct); ecache->ct = NULL; + +out_unlock: + rcu_read_unlock(); } /* Deliver all cached events for a particular conntrack. This is called @@ -111,26 +120,68 @@ void nf_conntrack_ecache_fini(struct net *net) free_percpu(net->ct.ecache); } -int nf_conntrack_register_notifier(struct notifier_block *nb) +int nf_conntrack_register_notifier(struct nf_ct_event_notifier *new) { - return atomic_notifier_chain_register(&nf_conntrack_chain, nb); + int ret = 0; + struct nf_ct_event_notifier *notify; + + mutex_lock(&nf_ct_ecache_mutex); + notify = rcu_dereference(nf_conntrack_event_cb); + if (notify != NULL) { + ret = -EBUSY; + goto out_unlock; + } + rcu_assign_pointer(nf_conntrack_event_cb, new); + mutex_unlock(&nf_ct_ecache_mutex); + return ret; + +out_unlock: + mutex_unlock(&nf_ct_ecache_mutex); + return ret; } EXPORT_SYMBOL_GPL(nf_conntrack_register_notifier); -int nf_conntrack_unregister_notifier(struct notifier_block *nb) +void nf_conntrack_unregister_notifier(struct nf_ct_event_notifier *new) { - return atomic_notifier_chain_unregister(&nf_conntrack_chain, nb); + struct nf_ct_event_notifier *notify; + + mutex_lock(&nf_ct_ecache_mutex); + notify = rcu_dereference(nf_conntrack_event_cb); + BUG_ON(notify != new); + rcu_assign_pointer(nf_conntrack_event_cb, NULL); + mutex_unlock(&nf_ct_ecache_mutex); } EXPORT_SYMBOL_GPL(nf_conntrack_unregister_notifier); -int nf_ct_expect_register_notifier(struct notifier_block *nb) +int nf_ct_expect_register_notifier(struct nf_exp_event_notifier *new) { - return atomic_notifier_chain_register(&nf_ct_expect_chain, nb); + int ret = 0; + struct nf_exp_event_notifier *notify; + + mutex_lock(&nf_ct_ecache_mutex); + notify = rcu_dereference(nf_expect_event_cb); + if (notify != NULL) { + ret = -EBUSY; + goto out_unlock; + } + rcu_assign_pointer(nf_expect_event_cb, new); + mutex_unlock(&nf_ct_ecache_mutex); + return ret; + +out_unlock: + mutex_unlock(&nf_ct_ecache_mutex); + return ret; } EXPORT_SYMBOL_GPL(nf_ct_expect_register_notifier); -int nf_ct_expect_unregister_notifier(struct notifier_block *nb) +void nf_ct_expect_unregister_notifier(struct nf_exp_event_notifier *new) { - return atomic_notifier_chain_unregister(&nf_ct_expect_chain, nb); + struct nf_exp_event_notifier *notify; + + mutex_lock(&nf_ct_ecache_mutex); + notify = rcu_dereference(nf_expect_event_cb); + BUG_ON(notify != new); + rcu_assign_pointer(nf_expect_event_cb, NULL); + mutex_unlock(&nf_ct_ecache_mutex); } EXPORT_SYMBOL_GPL(nf_ct_expect_unregister_notifier); |