Change how synchronization is done on the iptables counters. Use seqcount
wrapper instead of depending on reader/writer lock.
Signed-off-by: Stephen Hemminger <shemminger@xxxxxxxxxx>
---
include/linux/netfilter/x_tables.h | 2 +-
include/linux/netfilter_arp/arp_tables.h | 3 +++
include/linux/netfilter_ipv4/ip_tables.h | 3 +++
include/linux/netfilter_ipv6/ip6_tables.h | 3 +++
net/ipv4/netfilter/arp_tables.c | 20 +++++++++++++-------
net/ipv4/netfilter/ip_tables.c | 20 +++++++++++++-------
net/ipv6/netfilter/ip6_tables.c | 20 +++++++++++++-------
net/netfilter/x_tables.c | 1 +
8 files changed, 50 insertions(+), 22 deletions(-)
4
--- a/include/linux/netfilter_ipv6/ip6_tables.h 2009-01-27 15:03:02.843376881 -0800
+++ b/include/linux/netfilter_ipv6/ip6_tables.h 2009-01-27 15:37:38.935377810 -0800
@@ -103,6 +103,9 @@ struct ip6t_entry
/* Back pointer */
unsigned int comefrom;
+ /* Update of counter synchronization */
+ seqcount_t seq;
+
/* Packet and byte counters. */
struct xt_counters counters;
--- a/net/ipv4/netfilter/arp_tables.c 2009-01-27 14:48:41.579877551 -0800
+++ b/net/ipv4/netfilter/arp_tables.c 2009-01-27 15:45:34.566650540 -0800
@@ -256,7 +256,9 @@ unsigned int arpt_do_table(struct sk_buf
hdr_len = sizeof(*arp) + (2 * sizeof(struct in_addr)) +
(2 * skb->dev->addr_len);
+ write_seqcount_begin(&e->seq);
ADD_COUNTER(e->counters, hdr_len, 1);
+ write_seqcount_end(&e->seq);
t = arpt_get_target(e);
@@ -549,6 +551,7 @@ static inline int check_entry_size_and_h
< 0 (not ARPT_RETURN). --RR */
/* Clear counters and comefrom */
+ seqcount_init(&e->seq);
e->counters = ((struct xt_counters) { 0, 0 });
e->comefrom = 0;
@@ -703,14 +706,17 @@ static void get_counters(const struct xt
&i);
for_each_possible_cpu(cpu) {
+ struct arpt_entry *e = t->entries[cpu];
+ unsigned int start;
+
if (cpu == curcpu)
continue;
i = 0;
- ARPT_ENTRY_ITERATE(t->entries[cpu],
- t->size,
- add_entry_to_counter,
- counters,
- &i);
+ do {
+ start = read_seqcount_begin(&e->seq);
+ ARPT_ENTRY_ITERATE(t->entries[cpu], t->size,
+ add_entry_to_counter, counters, &i);
+ } while (read_seqcount_retry(&e->seq, start));
}
}
@@ -731,9 +737,9 @@ static inline struct xt_counters *alloc_
return ERR_PTR(-ENOMEM);
/* First, sum counters... */
- write_lock_bh(&table->lock);
+ local_bh_disable();
get_counters(private, counters);
- write_unlock_bh(&table->lock);
+ local_bh_enable();
return counters;
}
--- a/net/ipv4/netfilter/ip_tables.c 2009-01-27 14:48:41.567879095 -0800
+++ b/net/ipv4/netfilter/ip_tables.c 2009-01-27 15:45:05.766673246 -0800
@@ -366,7 +366,9 @@ ipt_do_table(struct sk_buff *skb,
if (IPT_MATCH_ITERATE(e, do_match, skb, &mtpar) != 0)
goto no_match;
+ write_seqcount_begin(&e->seq);
ADD_COUNTER(e->counters, ntohs(ip->tot_len), 1);
+ write_seqcount_end(&e->seq);
t = ipt_get_target(e);
IP_NF_ASSERT(t->u.kernel.target);
@@ -758,6 +760,7 @@ check_entry_size_and_hooks(struct ipt_en
< 0 (not IPT_RETURN). --RR */
/* Clear counters and comefrom */
+ seqcount_init(&e->seq);
e->counters = ((struct xt_counters) { 0, 0 });
e->comefrom = 0;
@@ -915,14 +918,17 @@ get_counters(const struct xt_table_info
&i);
for_each_possible_cpu(cpu) {
+ struct ipt_entry *e = t->entries[cpu];
+ unsigned int start;
+
if (cpu == curcpu)
continue;
i = 0;
- IPT_ENTRY_ITERATE(t->entries[cpu],
- t->size,
- add_entry_to_counter,
- counters,
- &i);
+ do {
+ start = read_seqcount_begin(&e->seq);
+ IPT_ENTRY_ITERATE(e, t->size,
+ add_entry_to_counter, counters, &i);
+ } while (read_seqcount_retry(&e->seq, start));
}
}
@@ -942,9 +948,9 @@ static struct xt_counters * alloc_counte
return ERR_PTR(-ENOMEM);
/* First, sum counters... */
- write_lock_bh(&table->lock);
+ local_bh_disable();
get_counters(private, counters);
- write_unlock_bh(&table->lock);
+ local_bh_enable();
return counters;
}
--- a/net/ipv6/netfilter/ip6_tables.c 2009-01-27 14:48:41.603877653 -0800
+++ b/net/ipv6/netfilter/ip6_tables.c 2009-01-27 15:45:22.262639173 -0800
@@ -392,9 +392,11 @@ ip6t_do_table(struct sk_buff *skb,
if (IP6T_MATCH_ITERATE(e, do_match, skb, &mtpar) != 0)
goto no_match;
+ write_seqcount_begin(&e->seq);
ADD_COUNTER(e->counters,
ntohs(ipv6_hdr(skb)->payload_len) +
sizeof(struct ipv6hdr), 1);
+ write_seqcount_end(&e->seq);
t = ip6t_get_target(e);
IP_NF_ASSERT(t->u.kernel.target);
@@ -787,6 +789,7 @@ check_entry_size_and_hooks(struct ip6t_e
< 0 (not IP6T_RETURN). --RR */
/* Clear counters and comefrom */
+ seqcount_init(&e->seq);
e->counters = ((struct xt_counters) { 0, 0 });
e->comefrom = 0;
@@ -944,14 +947,17 @@ get_counters(const struct xt_table_info
&i);
for_each_possible_cpu(cpu) {
+ struct ip6t_entry *e = t->entries[cpu];
+ unsigned int start;
+
if (cpu == curcpu)
continue;
i = 0;
- IP6T_ENTRY_ITERATE(t->entries[cpu],
- t->size,
- add_entry_to_counter,
- counters,
- &i);
+ do {
+ start = read_seqcount_begin(&e->seq);
+ IP6T_ENTRY_ITERATE(e, t->size,
+ add_entry_to_counter, counters, &i);
+ } while (read_seqcount_retry(&e->seq, start));
}
}
@@ -971,9 +977,9 @@ static struct xt_counters *alloc_counter
return ERR_PTR(-ENOMEM);
/* First, sum counters... */
- write_lock_bh(&table->lock);
+ local_bh_disable();
get_counters(private, counters);
- write_unlock_bh(&table->lock);
+ local_bh_enable();
return counters;
}
--- a/include/linux/netfilter_ipv4/ip_tables.h 2009-01-27 15:02:24.367376923 -0800
+++ b/include/linux/netfilter_ipv4/ip_tables.h 2009-01-27 15:16:43.940902866 -0800
@@ -91,6 +91,9 @@ struct ipt_entry
/* Back pointer */
unsigned int comefrom;
+ /* Update of counter synchronization */
+ seqcount_t seq;
+
/* Packet and byte counters. */
struct xt_counters counters;
--- a/net/netfilter/x_tables.c 2009-01-27 15:06:05.822878866 -0800
+++ b/net/netfilter/x_tables.c 2009-01-27 15:14:06.004743434 -0800
@@ -720,6 +720,7 @@ struct xt_table *xt_register_table(struc
/* Simplifies replace_table code. */
table->private = bootstrap;
rwlock_init(&table->lock);
+
if (!xt_replace_table(table, 0, newinfo, &ret))
goto unlock;
--- a/include/linux/netfilter/x_tables.h 2009-01-27 15:01:04.420377356 -0800
+++ b/include/linux/netfilter/x_tables.h 2009-01-27 15:33:10.791377313 -0800
@@ -385,7 +385,7 @@ struct xt_table_info
/* ipt_entry tables: one per CPU */
/* Note : this field MUST be the last one, see XT_TABLE_INFO_SZ */
- char *entries[1];
+ void *entries[1];
};
#define XT_TABLE_INFO_SZ (offsetof(struct xt_table_info, entries) \
--- a/include/linux/netfilter_arp/arp_tables.h 2009-01-27 15:35:33.827376817 -0800
+++ b/include/linux/netfilter_arp/arp_tables.h 2009-01-27 15:36:48.919127941 -0800
@@ -99,6 +99,9 @@ struct arpt_entry
/* Back pointer */
unsigned int comefrom;
+ /* Update of counter synchronization */
+ seqcount_t seq;
+
/* Packet and byte counters. */
struct xt_counters counters;
--
--
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