From mboxrd@z Thu Jan 1 00:00:00 1970 From: Giuseppe Scrivano Subject: [RFC PATCH] netfilter: call synchronize_net only once from nf_register_net_hooks Date: Wed, 22 Nov 2017 11:40:26 +0100 Message-ID: <20171122104026.7592-1-gscrivan@redhat.com> To: netfilter-devel@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:55368 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751575AbdKVKka (ORCPT ); Wed, 22 Nov 2017 05:40:30 -0500 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9D2BF6868E for ; Wed, 22 Nov 2017 10:40:30 +0000 (UTC) Sender: netfilter-devel-owner@vger.kernel.org List-ID: SELinux, if enabled, registers for each new network namespace 6 netfilter hooks. Avoid to use synchronize_net for each new hook, but do it once after all the hooks are added. The net benefit on an SMP machine with two cores is that creating a new network namespace takes -40% of the original time. Signed-off-by: Giuseppe Scrivano --- net/netfilter/core.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/net/netfilter/core.c b/net/netfilter/core.c index 52cd2901a097..beeb0b36f429 100644 --- a/net/netfilter/core.c +++ b/net/netfilter/core.c @@ -252,7 +252,7 @@ static struct nf_hook_entries __rcu **nf_hook_entry_head(struct net *net, const return NULL; } -int nf_register_net_hook(struct net *net, const struct nf_hook_ops *reg) +static int __nf_register_net_hook(struct net *net, const struct nf_hook_ops *reg) { struct nf_hook_entries *p, *new_hooks; struct nf_hook_entries __rcu **pp; @@ -291,11 +291,19 @@ int nf_register_net_hook(struct net *net, const struct nf_hook_ops *reg) #ifdef HAVE_JUMP_LABEL static_key_slow_inc(&nf_hooks_needed[reg->pf][reg->hooknum]); #endif - synchronize_net(); BUG_ON(p == new_hooks); kvfree(p); return 0; } + +int nf_register_net_hook(struct net *net, const struct nf_hook_ops *reg) +{ + int ret = __nf_register_net_hook(net, reg); + if (ret < 0) + return ret; + synchronize_net(); + return 0; +} EXPORT_SYMBOL(nf_register_net_hook); /* @@ -379,10 +387,11 @@ int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg, int err = 0; for (i = 0; i < n; i++) { - err = nf_register_net_hook(net, ®[i]); + err = __nf_register_net_hook(net, ®[i]); if (err) goto err; } + synchronize_net(); return err; err: -- 2.14.3