netfilter: x_tables: pass xt_counters struct to counter allocator

commit f28e15bacedd444608e25421c72eb2cf4527c9ca upstream.

Keeps some noise away from a followup patch.

Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

4 files changed, 33 insertions, 12 deletions

diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index e689deb95f1a..e4ac858385d3 100644
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -515,13 +515,10 @@ find_check_entry(struct arpt_entry *e, const char *name, unsigned int size)
 {
 	struct xt_entry_target *t;
 	struct xt_target *target;
-	unsigned long pcnt;
 	int ret;
 
-	pcnt = xt_percpu_counter_alloc();
-	if (IS_ERR_VALUE(pcnt))
+	if (!xt_percpu_counter_alloc(&e->counters))
 		return -ENOMEM;
-	e->counters.pcnt = pcnt;
 
 	t = arpt_get_target(e);
 	target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index 2d83604e3572..be7405aff963 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -657,12 +657,9 @@ find_check_entry(struct ipt_entry *e, struct net *net, const char *name,
 	unsigned int j;
 	struct xt_mtchk_param mtpar;
 	struct xt_entry_match *ematch;
-	unsigned long pcnt;
 
-	pcnt = xt_percpu_counter_alloc();
-	if (IS_ERR_VALUE(pcnt))
+	if (!xt_percpu_counter_alloc(&e->counters))
 		return -ENOMEM;
-	e->counters.pcnt = pcnt;
 
 	j = 0;
 	mtpar.net	= net;
diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c
index 274adecd6137..a4f39f7ca008 100644
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -670,12 +670,9 @@ find_check_entry(struct ip6t_entry *e, struct net *net, const char *name,
 	unsigned int j;
 	struct xt_mtchk_param mtpar;
 	struct xt_entry_match *ematch;
-	unsigned long pcnt;
 
-	pcnt = xt_percpu_counter_alloc();
-	if (IS_ERR_VALUE(pcnt))
+	if (!xt_percpu_counter_alloc(&e->counters))
 		return -ENOMEM;
-	e->counters.pcnt = pcnt;
 
 	j = 0;
 	mtpar.net	= net;
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index a8471220b11f..cfab40c59b9b 100644
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -1592,6 +1592,36 @@ void xt_proto_fini(struct net *net, u_int8_t af)
 }
 EXPORT_SYMBOL_GPL(xt_proto_fini);
 
+/**
+ * xt_percpu_counter_alloc - allocate x_tables rule counter
+ *
+ * @counter: pointer to counter struct inside the ip(6)/arpt_entry struct
+ *
+ * On SMP, the packet counter [ ip(6)t_entry->counters.pcnt ] will then
+ * contain the address of the real (percpu) counter.
+ *
+ * Rule evaluation needs to use xt_get_this_cpu_counter() helper
+ * to fetch the real percpu counter.
+ *
+ * returns false on error.
+ */
+bool xt_percpu_counter_alloc(struct xt_counters *counter)
+{
+	void __percpu *res;
+
+	if (nr_cpu_ids <= 1)
+		return true;
+
+	res = __alloc_percpu(sizeof(struct xt_counters),
+			     sizeof(struct xt_counters));
+	if (!res)
+		return false;
+
+	counter->pcnt = (__force unsigned long)res;
+	return true;
+}
+EXPORT_SYMBOL_GPL(xt_percpu_counter_alloc);
+
 void xt_percpu_counter_free(struct xt_counters *counters)
 {
 	unsigned long pcnt = counters->pcnt;