From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Westphal Subject: [PATCH nf-next 5/9] netfilter: conntrack: small refactoring of conntrack seq_printf Date: Thu, 28 Apr 2016 19:13:44 +0200 Message-ID: <1461863628-23350-6-git-send-email-fw@strlen.de> References: <1461863628-23350-1-git-send-email-fw@strlen.de> Cc: netdev@vger.kernel.org, Florian Westphal To: Return-path: Received: from Chamillionaire.breakpoint.cc ([80.244.247.6]:41575 "EHLO Chamillionaire.breakpoint.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753185AbcD1RNq (ORCPT ); Thu, 28 Apr 2016 13:13:46 -0400 In-Reply-To: <1461863628-23350-1-git-send-email-fw@strlen.de> Sender: netfilter-devel-owner@vger.kernel.org List-ID: The iteration process is lockless, so we test if the conntrack object is eligible for printing (e.g. is AF_INET) after obtaining the reference count. Once we put all conntracks into same hash table we might see more entries that need to be skipped. So add a helper and first perform the test in a lockless fashion for fast skip. Once we obtain the reference count, just repeat the check. Signed-off-by: Florian Westphal --- .../netfilter/nf_conntrack_l3proto_ipv4_compat.c | 24 +++++++++++++++++----- 1 file changed, 19 insertions(+), 5 deletions(-) diff --git a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4_compat.c b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4_compat.c index f0dfe92..483cf79 100644 --- a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4_compat.c +++ b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4_compat.c @@ -114,6 +114,19 @@ static inline void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct) } #endif +static bool ct_seq_should_skip(const struct nf_conn *ct, + const struct nf_conntrack_tuple_hash *hash) +{ + /* we only want to print DIR_ORIGINAL */ + if (NF_CT_DIRECTION(hash)) + return true; + + if (nf_ct_l3num(ct) != AF_INET) + return true; + + return false; +} + static int ct_seq_show(struct seq_file *s, void *v) { struct nf_conntrack_tuple_hash *hash = v; @@ -123,14 +136,15 @@ static int ct_seq_show(struct seq_file *s, void *v) int ret = 0; NF_CT_ASSERT(ct); - if (unlikely(!atomic_inc_not_zero(&ct->ct_general.use))) + if (ct_seq_should_skip(ct, hash)) return 0; + if (unlikely(!atomic_inc_not_zero(&ct->ct_general.use))) + return 0; - /* we only want to print DIR_ORIGINAL */ - if (NF_CT_DIRECTION(hash)) - goto release; - if (nf_ct_l3num(ct) != AF_INET) + /* check if we raced w. object reuse */ + if (!nf_ct_is_confirmed(ct) || + ct_seq_should_skip(ct, hash)) goto release; l3proto = __nf_ct_l3proto_find(nf_ct_l3num(ct)); -- 2.7.3