netfilter: nfnetlink: avoid recurrent netns lookups in call_batch

Pass the net pointer to the call_batch callback functions so we can skip
recurrent lookups.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Tested-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>

include/linux/netfilter/nfnetlink.h

@@ -14,7 +14,7 @@ struct nfnl_callback {
 	int (*call_rcu)(struct sock *nl, struct sk_buff *skb, 
 		    const struct nlmsghdr *nlh,
 		    const struct nlattr * const cda[]);
-	int (*call_batch)(struct sock *nl, struct sk_buff *skb,
+	int (*call_batch)(struct net *net, struct sock *nl, struct sk_buff *skb,
 			  const struct nlmsghdr *nlh,
 			  const struct nlattr * const cda[]);
 	const struct nla_policy *policy;	/* netlink attribute policy */

net/netfilter/nfnetlink.c

@@ -381,7 +381,7 @@ static void nfnetlink_rcv_batch(struct sk_buff *skb, struct nlmsghdr *nlh,
 				goto ack;
 
 			if (nc->call_batch) {
-				err = nc->call_batch(net->nfnl, skb, nlh,
+				err = nc->call_batch(net, net->nfnl, skb, nlh,
 						     (const struct nlattr **)cda);
 			}