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author | Taehee Yoo <ap420073@gmail.com> | 2017-07-19 08:27:33 +0300 |
---|---|---|
committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2017-07-24 14:24:46 +0300 |
commit | 0b35f6031a00329800bacc04085188c300c3a4d8 (patch) | |
tree | b4e34d6ab10b8b065583f1ce7c75ec05dea5a107 /net/netfilter/ipvs/ip_vs_core.c | |
parent | 9f08ea848117ab521efcfd3e004d8e1a0edc640c (diff) | |
download | linux-0b35f6031a00329800bacc04085188c300c3a4d8.tar.xz |
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 <ap420073@gmail.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/netfilter/ipvs/ip_vs_core.c')
-rw-r--r-- | net/netfilter/ipvs/ip_vs_core.c | 8 |
1 files changed, 0 insertions, 8 deletions
diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c index e31956b58aba..2ff9d9070c95 100644 --- a/net/netfilter/ipvs/ip_vs_core.c +++ b/net/netfilter/ipvs/ip_vs_core.c @@ -125,14 +125,12 @@ ip_vs_in_stats(struct ip_vs_conn *cp, struct sk_buff *skb) s->cnt.inbytes += skb->len; u64_stats_update_end(&s->syncp); - rcu_read_lock(); svc = rcu_dereference(dest->svc); s = this_cpu_ptr(svc->stats.cpustats); u64_stats_update_begin(&s->syncp); s->cnt.inpkts++; s->cnt.inbytes += skb->len; u64_stats_update_end(&s->syncp); - rcu_read_unlock(); s = this_cpu_ptr(ipvs->tot_stats.cpustats); u64_stats_update_begin(&s->syncp); @@ -159,14 +157,12 @@ ip_vs_out_stats(struct ip_vs_conn *cp, struct sk_buff *skb) s->cnt.outbytes += skb->len; u64_stats_update_end(&s->syncp); - rcu_read_lock(); svc = rcu_dereference(dest->svc); s = this_cpu_ptr(svc->stats.cpustats); u64_stats_update_begin(&s->syncp); s->cnt.outpkts++; s->cnt.outbytes += skb->len; u64_stats_update_end(&s->syncp); - rcu_read_unlock(); s = this_cpu_ptr(ipvs->tot_stats.cpustats); u64_stats_update_begin(&s->syncp); @@ -1222,7 +1218,6 @@ static struct ip_vs_conn *__ip_vs_rs_conn_out(unsigned int hooknum, if (!pptr) return NULL; - rcu_read_lock(); dest = ip_vs_find_real_service(ipvs, af, iph->protocol, &iph->saddr, pptr[0]); if (dest) { @@ -1237,7 +1232,6 @@ static struct ip_vs_conn *__ip_vs_rs_conn_out(unsigned int hooknum, pptr[0], pptr[1]); } } - rcu_read_unlock(); return cp; } @@ -1689,11 +1683,9 @@ ip_vs_in_icmp(struct netns_ipvs *ipvs, struct sk_buff *skb, int *related, if (dest) { struct ip_vs_dest_dst *dest_dst; - rcu_read_lock(); dest_dst = rcu_dereference(dest->dest_dst); if (dest_dst) mtu = dst_mtu(dest_dst->dst_cache); - rcu_read_unlock(); } if (mtu > 68 + sizeof(struct iphdr)) mtu -= sizeof(struct iphdr); |