ovs: Turn vports with dependencies into separate modules

The internal and netdev vport remain part of openvswitch.ko. Encap
vports including vxlan, gre, and geneve can be built as separate
modules and are loaded on demand. Modules can be unloaded after use.
Datapath ports keep a reference to the vport module during their
lifetime.

Allows to remove the error prone maintenance of the global list
vport_ops_list.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/openvswitch/Kconfig

@@ -29,11 +29,11 @@ config OPENVSWITCH
 	  If unsure, say N.
 
 config OPENVSWITCH_GRE
-	bool "Open vSwitch GRE tunneling support"
+	tristate "Open vSwitch GRE tunneling support"
 	depends on INET
 	depends on OPENVSWITCH
-	depends on NET_IPGRE_DEMUX && !(OPENVSWITCH=y && NET_IPGRE_DEMUX=m)
-	default y
+	depends on NET_IPGRE_DEMUX
+	default OPENVSWITCH
 	---help---
 	  If you say Y here, then the Open vSwitch will be able create GRE
 	  vport.
@@ -43,11 +43,11 @@ config OPENVSWITCH_GRE
 	  If unsure, say Y.
 
 config OPENVSWITCH_VXLAN
-	bool "Open vSwitch VXLAN tunneling support"
+	tristate "Open vSwitch VXLAN tunneling support"
 	depends on INET
 	depends on OPENVSWITCH
-	depends on VXLAN && !(OPENVSWITCH=y && VXLAN=m)
-	default y
+	depends on VXLAN
+	default OPENVSWITCH
 	---help---
 	  If you say Y here, then the Open vSwitch will be able create vxlan vport.
 
@@ -56,11 +56,11 @@ config OPENVSWITCH_VXLAN
 	  If unsure, say Y.
 
 config OPENVSWITCH_GENEVE
-	bool "Open vSwitch Geneve tunneling support"
+	tristate "Open vSwitch Geneve tunneling support"
 	depends on INET
 	depends on OPENVSWITCH
-	depends on GENEVE && !(OPENVSWITCH=y && GENEVE=m)
-	default y
+	depends on GENEVE
+	default OPENVSWITCH
 	---help---
 	  If you say Y here, then the Open vSwitch will be able create geneve vport.