On Wed, Feb 25, 2015 at 08:15:43PM -0600, Eric W. Biederman wrote:

Simon Horman [off-list ref] writes:

quoted

On Wed, Feb 25, 2015 at 11:13:02AM -0600, Eric W. Biederman wrote:

quoted

This refactoring is needed to allow more than just mpls gso support to
be built into the mpls moddule.

Signed-off-by: "Eric W. Biederman" <redacted>
---
 net/Makefile     |  2 +-
 net/mpls/Kconfig | 18 +++++++++++++++++-
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/net/Makefile b/net/Makefile
index 38704bdf941a..3995613e5510 100644
--- a/net/Makefile
+++ b/net/Makefile

@@ -69,7 +69,7 @@ obj-$(CONFIG_BATMAN_ADV)	+= batman-adv/
 obj-$(CONFIG_NFC)		+= nfc/
 obj-$(CONFIG_OPENVSWITCH)	+= openvswitch/
 obj-$(CONFIG_VSOCKETS)	+= vmw_vsock/
-obj-$(CONFIG_NET_MPLS_GSO)	+= mpls/
+obj-$(CONFIG_MPLS)		+= mpls/
 obj-$(CONFIG_HSR)		+= hsr/
 ifneq ($(CONFIG_NET_SWITCHDEV),)
 obj-y				+= switchdev/

diff --git a/net/mpls/Kconfig b/net/mpls/Kconfig
index 37421db88965..a77fbcdd04ee 100644
--- a/net/mpls/Kconfig
+++ b/net/mpls/Kconfig

@@ -1,9 +1,25 @@
 #
 # MPLS configuration
 #
+
+menuconfig MPLS
+	tristate "MultiProtocol Label Switching"
+	default n
+	---help---
+	  MultiProtocol Label Switching routes packets through logical
+	  circuits.  Originally conceved as a way of routing packets at
+	  hardware speeds (before hardware was capable of routing ipv4 packets),
+	  MPLS remains as simple way of making tunnels.
+
+	  If you have not heard of MPLS you probably want to say N here.
+
+if MPLS
+
 config NET_MPLS_GSO
-	tristate "MPLS: GSO support"
+	bool "MPLS: GSO support"
 	help
 	 This is helper module to allow segmentation of non-MPLS GSO packets
 	 that have had MPLS stack entries pushed onto them and thus
 	 become MPLS GSO packets.
+
+endif # MPLS

Is the implication here that MPLS must be selected to allow NET_MPLS_GSO to
be selected? That is if NET_MPLS_GSO is to be used to handle MPLS packets
emitted by OVS then now MPLS also needs to be selected?

Yes.

That is the way we seem to handle this for other protocols and I could
not see an easy way to build multiple modules from a single Makefile.

I am a tad afraid that this Kconfig clause will cause problems with
make oldconfig as it stands, and I will be happy to take suggestions
on how to do this better.

The other MPLS bits that are added in the following patches are behind
their own Kconfig options so there is no danger in getting more MPLS
code than desired.

Thanks, that part seems reasonable to me.

I'm also unsure of a better way to handle this.

Reviewed-by: Simon Horman <horms@verge.net.au>