openvswitch: Simplify datapath locking.

Currently OVS uses combination of genl and rtnl lock to protect
datapath state.  This was done due to networking stack locking.
But this has complicated locking and there are few lock ordering
issues with new tunneling protocols.
Following patch simplifies locking by introducing new ovs mutex
and now this lock is used to protect entire ovs state.

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: Jesse Gross <jesse@nicira.com>
diff --git a/net/openvswitch/vport.h b/net/openvswitch/vport.h
index aee7d43..7282b84 100644
--- a/net/openvswitch/vport.h
+++ b/net/openvswitch/vport.h
@@ -138,14 +138,14 @@
 struct vport_ops {
 	enum ovs_vport_type type;
 
-	/* Called with RTNL lock. */
+	/* Called with ovs_mutex. */
 	struct vport *(*create)(const struct vport_parms *);
 	void (*destroy)(struct vport *);
 
 	int (*set_options)(struct vport *, struct nlattr *);
 	int (*get_options)(const struct vport *, struct sk_buff *);
 
-	/* Called with rcu_read_lock or RTNL lock. */
+	/* Called with rcu_read_lock or ovs_mutex. */
 	const char *(*get_name)(const struct vport *);
 	void (*get_config)(const struct vport *, void *);
 	int (*get_ifindex)(const struct vport *);