netfilter: nf_conntrack: use per-conntrack locks for protocol data

Introduce per-conntrack locks and use them instead of the global protocol
locks to avoid contention. Especially tcp_lock shows up very high in
profiles on larger machines.

This will also allow to simplify the upcoming reliable event delivery patches.

Signed-off-by: Patrick McHardy <kaber@trash.net>

include/net/netfilter/nf_conntrack.h

@@ -93,6 +93,8 @@ struct nf_conn {
            plus 1 for any connection(s) we are `master' for */
 	struct nf_conntrack ct_general;
 
+	spinlock_t lock;
+
 	/* XXX should I move this to the tail ? - Y.K */
 	/* These are my tuples; original and reply */
 	struct nf_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX];

include/net/netfilter/nf_conntrack_l4proto.h

@@ -59,11 +59,11 @@ struct nf_conntrack_l4proto
 			   const struct nf_conntrack_tuple *);
 
 	/* Print out the private part of the conntrack. */
-	int (*print_conntrack)(struct seq_file *s, const struct nf_conn *);
+	int (*print_conntrack)(struct seq_file *s, struct nf_conn *);
 
 	/* convert protoinfo to nfnetink attributes */
 	int (*to_nlattr)(struct sk_buff *skb, struct nlattr *nla,
-			 const struct nf_conn *ct);
+			 struct nf_conn *ct);
 	/* Calculate protoinfo nlattr size */
 	int (*nlattr_size)(void);