From 0b35f6031a00329800bacc04085188c300c3a4d8 Mon Sep 17 00:00:00 2001 From: Taehee Yoo Date: Wed, 19 Jul 2017 14:27:33 +0900 Subject: netfilter: Remove duplicated rcu_read_lock. This patch removes duplicate rcu_read_lock(). 1. IPVS part: According to Julian Anastasov's mention, contexts of ipvs are described at: http://marc.info/?l=netfilter-devel&m=149562884514072&w=2, in summary: - packet RX/TX: does not need locks because packets come from hooks. - sync msg RX: backup server uses RCU locks while registering new connections. - ip_vs_ctl.c: configuration get/set, RCU locks needed. - xt_ipvs.c: It is a netfilter match, running from hook context. As result, rcu_read_lock and rcu_read_unlock can be removed from: - ip_vs_core.c: all - ip_vs_ctl.c: - only from ip_vs_has_real_service - ip_vs_ftp.c: all - ip_vs_proto_sctp.c: all - ip_vs_proto_tcp.c: all - ip_vs_proto_udp.c: all - ip_vs_xmit.c: all (contains only packet processing) 2. Netfilter part: There are three types of functions that are guaranteed the rcu_read_lock(). First, as result, functions are only called by nf_hook(): - nf_conntrack_broadcast_help(), pptp_expectfn(), set_expected_rtp_rtcp(). - tcpmss_reverse_mtu(), tproxy_laddr4(), tproxy_laddr6(). - match_lookup_rt6(), check_hlist(), hashlimit_mt_common(). - xt_osf_match_packet(). Second, functions that caller already held the rcu_read_lock(). - destroy_conntrack(), ctnetlink_conntrack_event(). - ctnl_timeout_find_get(), nfqnl_nf_hook_drop(). Third, functions that are mixed with type1 and type2. These functions are called by nf_hook() also these are called by ordinary functions that already held the rcu_read_lock(): - __ctnetlink_glue_build(), ctnetlink_expect_event(). - ctnetlink_proto_size(). Applied files are below: - nf_conntrack_broadcast.c, nf_conntrack_core.c, nf_conntrack_netlink.c. - nf_conntrack_pptp.c, nf_conntrack_sip.c, nfnetlink_cttimeout.c. - nfnetlink_queue.c, xt_TCPMSS.c, xt_TPROXY.c, xt_addrtype.c. - xt_connlimit.c, xt_hashlimit.c, xt_osf.c Detailed calltrace can be found at: http://marc.info/?l=netfilter-devel&m=149667610710350&w=2 Signed-off-by: Taehee Yoo Acked-by: Julian Anastasov Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_netlink.c | 12 ------------ 1 file changed, 12 deletions(-) (limited to 'net/netfilter/nf_conntrack_netlink.c') diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index 7999e70c3bfb..4dba71de4de7 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -539,13 +539,11 @@ static inline size_t ctnetlink_proto_size(const struct nf_conn *ct) struct nf_conntrack_l4proto *l4proto; size_t len = 0; - rcu_read_lock(); l3proto = __nf_ct_l3proto_find(nf_ct_l3num(ct)); len += l3proto->nla_size; l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct)); len += l4proto->nla_size; - rcu_read_unlock(); return len; } @@ -664,7 +662,6 @@ ctnetlink_conntrack_event(unsigned int events, struct nf_ct_event *item) nfmsg->version = NFNETLINK_V0; nfmsg->res_id = 0; - rcu_read_lock(); zone = nf_ct_zone(ct); nest_parms = nla_nest_start(skb, CTA_TUPLE_ORIG | NLA_F_NESTED); @@ -736,8 +733,6 @@ ctnetlink_conntrack_event(unsigned int events, struct nf_ct_event *item) && ctnetlink_dump_mark(skb, ct) < 0) goto nla_put_failure; #endif - rcu_read_unlock(); - nlmsg_end(skb, nlh); err = nfnetlink_send(skb, net, item->portid, group, item->report, GFP_ATOMIC); @@ -747,7 +742,6 @@ ctnetlink_conntrack_event(unsigned int events, struct nf_ct_event *item) return 0; nla_put_failure: - rcu_read_unlock(); nlmsg_cancel(skb, nlh); nlmsg_failure: kfree_skb(skb); @@ -2213,7 +2207,6 @@ static int __ctnetlink_glue_build(struct sk_buff *skb, struct nf_conn *ct) const struct nf_conntrack_zone *zone; struct nlattr *nest_parms; - rcu_read_lock(); zone = nf_ct_zone(ct); nest_parms = nla_nest_start(skb, CTA_TUPLE_ORIG | NLA_F_NESTED); @@ -2272,11 +2265,9 @@ static int __ctnetlink_glue_build(struct sk_buff *skb, struct nf_conn *ct) #endif if (ctnetlink_dump_labels(skb, ct) < 0) goto nla_put_failure; - rcu_read_unlock(); return 0; nla_put_failure: - rcu_read_unlock(); return -ENOSPC; } @@ -2661,17 +2652,14 @@ ctnetlink_expect_event(unsigned int events, struct nf_exp_event *item) nfmsg->version = NFNETLINK_V0; nfmsg->res_id = 0; - rcu_read_lock(); if (ctnetlink_exp_dump_expect(skb, exp) < 0) goto nla_put_failure; - rcu_read_unlock(); nlmsg_end(skb, nlh); nfnetlink_send(skb, net, item->portid, group, item->report, GFP_ATOMIC); return 0; nla_put_failure: - rcu_read_unlock(); nlmsg_cancel(skb, nlh); nlmsg_failure: kfree_skb(skb); -- cgit v1.2.3