openvswitch: Allow each vport to have an array of 'port_id's.

In order to allow handlers directly read upcalls from datapath,
we need to support per-handler netlink socket for each vport in
datapath.  This commit makes this happen.  Also, it is guaranteed
to be backward compatible with previous branch.

Signed-off-by: Alex Wang <alexw@nicira.com>
Acked-by: Thomas Graf <tgraf@redhat.com>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
diff --git a/net/openvswitch/vport.h b/net/openvswitch/vport.h
index 8d721e6..35f89d8 100644
--- a/net/openvswitch/vport.h
+++ b/net/openvswitch/vport.h
@@ -23,6 +23,7 @@
 #include <linux/list.h>
 #include <linux/netlink.h>
 #include <linux/openvswitch.h>
+#include <linux/reciprocal_div.h>
 #include <linux/skbuff.h>
 #include <linux/spinlock.h>
 #include <linux/u64_stats_sync.h>
@@ -52,6 +53,10 @@
 int ovs_vport_set_options(struct vport *, struct nlattr *options);
 int ovs_vport_get_options(const struct vport *, struct sk_buff *);
 
+int ovs_vport_set_upcall_portids(struct vport *, struct nlattr *pids);
+int ovs_vport_get_upcall_portids(const struct vport *, struct sk_buff *);
+u32 ovs_vport_find_upcall_portid(const struct vport *, struct sk_buff *);
+
 int ovs_vport_send(struct vport *, struct sk_buff *);
 
 /* The following definitions are for implementers of vport devices: */
@@ -62,13 +67,27 @@
 	u64 tx_dropped;
 	u64 tx_errors;
 };
+/**
+ * struct vport_portids - array of netlink portids of a vport.
+ *                        must be protected by rcu.
+ * @rn_ids: The reciprocal value of @n_ids.
+ * @rcu: RCU callback head for deferred destruction.
+ * @n_ids: Size of @ids array.
+ * @ids: Array storing the Netlink socket pids to be used for packets received
+ * on this port that miss the flow table.
+ */
+struct vport_portids {
+	struct reciprocal_value rn_ids;
+	struct rcu_head rcu;
+	u32 n_ids;
+	u32 ids[];
+};
 
 /**
  * struct vport - one port within a datapath
  * @rcu: RCU callback head for deferred destruction.
  * @dp: Datapath to which this port belongs.
- * @upcall_portid: The Netlink port to use for packets received on this port that
- * miss the flow table.
+ * @upcall_portids: RCU protected 'struct vport_portids'.
  * @port_no: Index into @dp's @ports array.
  * @hash_node: Element in @dev_table hash table in vport.c.
  * @dp_hash_node: Element in @datapath->ports hash table in datapath.c.
@@ -80,7 +99,7 @@
 struct vport {
 	struct rcu_head rcu;
 	struct datapath	*dp;
-	u32 upcall_portid;
+	struct vport_portids __rcu *upcall_portids;
 	u16 port_no;
 
 	struct hlist_node hash_node;
@@ -111,7 +130,7 @@
 	/* For ovs_vport_alloc(). */
 	struct datapath *dp;
 	u16 port_no;
-	u32 upcall_portid;
+	struct nlattr *upcall_portids;
 };
 
 /**