[PATCH 1/3][SRU][Y, Z] 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>
(cherry picked 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    | 5 ++---
 net/netfilter/x_tables.c           | 9 +++++++++
 5 files changed, 16 insertions(+), 12 deletions(-)

diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h
index 2ad1a2b..dfd56c1 100644
--- a/include/linux/netfilter/x_tables.h
+++ b/include/linux/netfilter/x_tables.h
@@ -402,11 +402,7 @@ static inline unsigned long 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 624b0fd..a2be65c 100644
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -460,7 +460,7 @@ 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;
 }
@@ -540,7 +540,7 @@ 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 ebaed2b..7c25dd4 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -603,7 +603,7 @@ 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;
 }
@@ -691,7 +691,7 @@ 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 063217e..862e20f 100644
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -633,7 +633,7 @@ 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;
 }
@@ -720,8 +720,7 @@ static void cleanup_entry(struct ip6t_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/netfilter/x_tables.c b/net/netfilter/x_tables.c
index fc49774..93703c9 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -1615,6 +1615,15 @@ 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