[PATCH 1/3][SRU][X] netfilter: x_tables: pass xt_counters struct instead of packet counter

[Eric Desrochers]

From: Florian Westphal <fw at strlen.de>

BugLink: https://bugs.launchpad.net/bugs/1640786

On SMP we overload the packet counter (unsigned long) to contain
percpu offset.  Hide this from callers and pass xt_counters address
instead.

Preparation patch to allocate the percpu counters in page-sized batch
chunks.

Signed-off-by: Florian Westphal <fw at strlen.de>
Acked-by: Eric Dumazet <edumazet at google.com>
Signed-off-by: Pablo Neira Ayuso <pablo at netfilter.org>
(backported from commit 4d31eef5176df06f218201bc9c0ce40babb41660)
Signed-off-by: Eric Desrochers <eric.desrochers at canonical.com>
---
 include/linux/netfilter/x_tables.h | 6 +-----
 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           | 9 +++++++++
 5 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h
index 04078e8..b923cc7 100644
--- a/include/linux/netfilter/x_tables.h
+++ b/include/linux/netfilter/x_tables.h
@@ -391,11 +391,7 @@ static inline u64 xt_percpu_counter_alloc(void)
 
 	return 0;
 }
-static inline void xt_percpu_counter_free(u64 pcnt)
-{
-	if (nr_cpu_ids > 1)
-		free_percpu((void __percpu *) (unsigned long) pcnt);
-}
+void xt_percpu_counter_free(struct xt_counters *cnt);
 
 static inline struct xt_counters *
 xt_get_this_cpu_counter(struct xt_counters *cnt)
diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index 7563651..6219e80 100644
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -553,7 +553,7 @@ find_check_entry(struct arpt_entry *e, const char *name, unsigned int size)
 err:
 	module_put(t->u.kernel.target->me);
 out:
-	xt_percpu_counter_free(e->counters.pcnt);
+	xt_percpu_counter_free(&e->counters);
 
 	return ret;
 }
@@ -641,7 +641,7 @@ static inline void cleanup_entry(struct arpt_entry *e)
 	if (par.target->destroy != NULL)
 		par.target->destroy(&par);
 	module_put(par.target->me);
-	xt_percpu_counter_free(e->counters.pcnt);
+	xt_percpu_counter_free(&e->counters);
 }
 
 /* Checks and translates the user-supplied table segment (held in
diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index f355884..e6e3499 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -715,7 +715,7 @@ find_check_entry(struct ipt_entry *e, struct net *net, const char *name,
 		cleanup_match(ematch, net);
 	}
 
-	xt_percpu_counter_free(e->counters.pcnt);
+	xt_percpu_counter_free(&e->counters);
 
 	return ret;
 }
@@ -811,7 +811,7 @@ cleanup_entry(struct ipt_entry *e, struct net *net)
 	if (par.target->destroy != NULL)
 		par.target->destroy(&par);
 	module_put(par.target->me);
-	xt_percpu_counter_free(e->counters.pcnt);
+	xt_percpu_counter_free(&e->counters);
 }
 
 /* Checks and translates the user-supplied table segment (held in
diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c
index ec2733e..e1d2b64 100644
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -727,7 +727,7 @@ find_check_entry(struct ip6t_entry *e, struct net *net, const char *name,
 		cleanup_match(ematch, net);
 	}
 
-	xt_percpu_counter_free(e->counters.pcnt);
+	xt_percpu_counter_free(&e->counters);
 
 	return ret;
 }
@@ -823,7 +823,7 @@ static void cleanup_entry(struct ip6t_entry *e, struct net *net)
 		par.target->destroy(&par);
 	module_put(par.target->me);
 
-	xt_percpu_counter_free(e->counters.pcnt);
+	xt_percpu_counter_free(&e->counters);
 }
 
 /* Checks and translates the user-supplied table segment (held in
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index 9e6f752..847063c 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -1550,6 +1550,15 @@ void xt_proto_fini(struct net *net, u_int8_t af)
 }
 EXPORT_SYMBOL_GPL(xt_proto_fini);
 
+void xt_percpu_counter_free(struct xt_counters *counters)
+{
+       unsigned long pcnt = counters->pcnt;
+
+       if (nr_cpu_ids > 1)
+               free_percpu((void __percpu *)pcnt);
+}
+EXPORT_SYMBOL_GPL(xt_percpu_counter_free);
+
 static int __net_init xt_net_init(struct net *net)
 {
 	int i;
-- 
2.7.4