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 | 14 +++-----------
net/ipv4/netfilter/arp_tables.c | 4 ++--
net/ipv4/netfilter/ip_tables.c | 4 ++--
net/ipv6/netfilter/ip6_tables.c | 4 ++--
net/netfilter/x_tables.c | 28 ++++++++++++++++++++++++++++
5 files changed, 37 insertions(+), 17 deletions(-)
4
--- a/net/ipv4/netfilter/arp_tables.c 2009-01-29 11:08:38.735069921 -0800
+++ b/net/ipv4/netfilter/arp_tables.c 2009-01-29 11:09:20.720069979 -0800
@@ -736,9 +736,9 @@ 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 2009-01-29 11:08:38.723069778 -0800
+++ b/net/ipv4/netfilter/ip_tables.c 2009-01-29 11:09:20.720069979 -0800
@@ -947,9 +947,9 @@ 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 2009-01-29 11:08:38.763071181 -0800
+++ b/net/ipv6/netfilter/ip6_tables.c 2009-01-29 11:09:20.724069866 -0800
@@ -976,9 +976,9 @@ 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/net/netfilter/x_tables.c 2009-01-29 11:08:38.747070716 -0800
+++ b/net/netfilter/x_tables.c 2009-01-29 11:10:03.595571234 -0800
@@ -577,6 +577,34 @@ int xt_compat_target_to_user(struct xt_e
EXPORT_SYMBOL_GPL(xt_compat_target_to_user);
#endif
+static DEFINE_PER_CPU(seqcount_t, xt_counter_sequence);
+
+void xt_fetch_counter(struct xt_counters *v, int cpu,
+ const struct xt_counters *c)
+{
+ seqcount_t *seq = &per_cpu(xt_counter_sequence, cpu);
+ unsigned start;
+
+ do {
+ start = read_seqcount_begin(seq);
+ *v = *c;
+ } while (read_seqcount_retry(seq, start));
+}
+EXPORT_SYMBOL_GPL(xt_fetch_counter);
+
+void xt_incr_counter(struct xt_counters *c, unsigned b, unsigned p)
+{
+ seqcount_t *seq = &__get_cpu_var(xt_counter_sequence);
+
+ write_seqcount_begin(seq);
+ c->pcnt += p;
+ c->bcnt += b;
+ write_seqcount_end(seq);
+
+}
+EXPORT_SYMBOL_GPL(xt_incr_counter);
+
+
struct xt_table_info *xt_alloc_table_info(unsigned int size)
{
struct xt_table_info *newinfo;
--- a/include/linux/netfilter/x_tables.h 2009-01-29 11:08:38.779071484 -0800
+++ b/include/linux/netfilter/x_tables.h 2009-01-29 11:09:20.724069866 -0800
@@ -112,17 +112,9 @@ struct xt_counters
u_int64_t pcnt, bcnt; /* Packet and byte counters */
};
-static inline void xt_fetch_counter(struct xt_counters *v, int cpu,
- const struct xt_counters *c)
-{
- *v = *c;
-}
-
-static inline void xt_incr_counter(struct xt_counters *c, unsigned b, unsigned p)
-{
- c->pcnt += p;
- c->bcnt += b;
-}
+extern void xt_fetch_counter(struct xt_counters *v, int cpu,
+ const struct xt_counters *c);
+extern void xt_incr_counter(struct xt_counters *c, unsigned b, unsigned p);
/* The argument to IPT_SO_ADD_COUNTERS. */
--
--
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