From 308ff823ebd749a94d3b6ac26b95bc0eb114c39e Mon Sep 17 00:00:00 2001 From: Jesper Dangaard Brouer Date: Thu, 25 Jun 2009 16:32:52 +0200 Subject: [PATCH] nf_conntrack: Use rcu_barrier() RCU barriers, rcu_barrier(), is inserted two places. In nf_conntrack_expect.c nf_conntrack_expect_fini() before the kmem_cache_destroy(). Firstly to make sure the callback to the nf_ct_expect_free_rcu() code is still around. Secondly because I'm unsure about the consequence of having in flight nf_ct_expect_free_rcu/kmem_cache_free() calls while doing a kmem_cache_destroy() slab destroy. And in nf_conntrack_extend.c nf_ct_extend_unregister(), inorder to wait for completion of callbacks to __nf_ct_ext_free_rcu(), which is invoked by __nf_ct_ext_add(). It might be more efficient to call rcu_barrier() in nf_conntrack_core.c nf_conntrack_cleanup_net(), but thats make it more difficult to read the code (as the callback code in located in nf_conntrack_extend.c). Signed-off-by: Jesper Dangaard Brouer Signed-off-by: Patrick McHardy --- net/netfilter/nf_conntrack_expect.c | 4 +++- net/netfilter/nf_conntrack_extend.c | 2 +- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/net/netfilter/nf_conntrack_expect.c b/net/netfilter/nf_conntrack_expect.c index afde8f991646..2032dfe25ca8 100644 --- a/net/netfilter/nf_conntrack_expect.c +++ b/net/netfilter/nf_conntrack_expect.c @@ -617,8 +617,10 @@ err1: void nf_conntrack_expect_fini(struct net *net) { exp_proc_remove(net); - if (net_eq(net, &init_net)) + if (net_eq(net, &init_net)) { + rcu_barrier(); /* Wait for call_rcu() before destroy */ kmem_cache_destroy(nf_ct_expect_cachep); + } nf_ct_free_hashtable(net->ct.expect_hash, net->ct.expect_vmalloc, nf_ct_expect_hsize); } diff --git a/net/netfilter/nf_conntrack_extend.c b/net/netfilter/nf_conntrack_extend.c index 4b2c769d555f..fef95be334bd 100644 --- a/net/netfilter/nf_conntrack_extend.c +++ b/net/netfilter/nf_conntrack_extend.c @@ -186,6 +186,6 @@ void nf_ct_extend_unregister(struct nf_ct_ext_type *type) rcu_assign_pointer(nf_ct_ext_types[type->id], NULL); update_alloc_size(type); mutex_unlock(&nf_ct_ext_type_mutex); - synchronize_rcu(); + rcu_barrier(); /* Wait for completion of call_rcu()'s */ } EXPORT_SYMBOL_GPL(nf_ct_extend_unregister); -- 2.20.1