[PATCH net-next 0/6] openvswitch: remove support for legacy tunnel ports

[Ilya Maximets <i.maximets@ovn.org>]

ovs-vswitchd doesn't use OVS_VPORT_TYPE_GRE/VXLAN/GENEVE with the
Linux kernel module since adding support for standard tunnel devices
with COLLECT_METADATA back in 2017.  The code to use them was only
activated as a fallback for old kernels, so not used in practice.  And
it is now fully removed in the upcoming OVS 4.0 release.

Modern way to use tunnels with OVS is to create standard tunnel ports
with RTM_NEWLINK + COLLECT_METADATA and add them as OVS_VPORT_TYPE_NETDEV.

Device reference management and the netlink options parsing for these
legacy port types is complicated and was a CVE magnet in the previous
release cycles.  Existence of these modules also makes locking analysis
for geneve module and other core tunnel devices unnecessarily more
complicated, especially in light of migration to per-netns locking:
  https://lore.kernel.org/r/CAAVpQUDmZEaQNDSySLayqexgTrUbhBaL7XPCt9XNQzh+NGQ=UQ@mail.gmail.com

Since there are no actual users for these port types for a very long
time, let's just remove the support entirely.  There is no practical
reason to run OVS from 2017 on a recent kernel.

While it's technically a uAPI change in some sense, from the user's
perspective this removal looks indistinguishable from the kernel built
with CONFIG_OPENVSWITCH_GENEVE/VXLAN/GRE disabled.  And it seems like
removal of unused drivers/modules is not a rare event these days.


There are 3 parts to this set:

1. The first patch does the tunnel port removal, which is the primary
   goal here.

2. Patches 2 and 3 remove extra infrastructure that is no longer in
   use by anything inside the openvswitch module.

3. Patches 4-6 remove functions from gre/vxlan/geneve modules that
   were added for openvswitch in the past to support the tunnel types.
   openvswitch is the only in-tree consumer of these functions.


Version 1:
 - Rebased.
 - Removed the tunnel modules from the new OVS selftest config.
 - Addressed RFC review from Sashiko:
   * Made ovs_netdev_link() static.
   * Restored -EOPNOTSUPP if OVS_VPORT_ATTR_OPTIONS was provided.
   * Removed retry in ovs_vport_cmd_new() as not needed anymore.

RFC:
 - https://lore.kernel.org/r/20260513183559.2141010-1-i.maximets@ovn.org

Ilya Maximets (6):
  openvswitch: remove support for legacy tunnel types
  openvswitch: vport: remove infrastructure for vport options
  openvswitch: vport: remove infrastructure for separate modules
  net: geneve: remove unused geneve_dev_create_fb
  net: gre: remove unused gretap_fb_dev_create
  net: vxlan: remove unused vxlan_dev_create

 drivers/net/geneve.c                          |  49 -----
 drivers/net/vxlan/vxlan_core.c                |  42 +----
 include/net/geneve.h                          |   5 -
 include/net/gre.h                             |   2 -
 include/net/vxlan.h                           |   3 -
 include/uapi/linux/openvswitch.h              |  31 +++-
 net/ipv4/ip_gre.c                             |  47 -----
 net/openvswitch/Kconfig                       |  35 ----
 net/openvswitch/Makefile                      |   4 -
 net/openvswitch/datapath.c                    |  28 +--
 net/openvswitch/vport-geneve.c                | 143 ---------------
 net/openvswitch/vport-gre.c                   | 106 -----------
 net/openvswitch/vport-netdev.c                |  29 +--
 net/openvswitch/vport-netdev.h                |   2 -
 net/openvswitch/vport-vxlan.c                 | 172 ------------------
 net/openvswitch/vport.c                       |  79 +-------
 net/openvswitch/vport.h                       |  23 +--
 tools/testing/selftests/net/config            |   3 -
 .../testing/selftests/net/openvswitch/config  |   3 -
 .../selftests/net/openvswitch/openvswitch.sh  |  38 ----
 .../selftests/net/openvswitch/ovs-dpctl.py    |  93 +++-------
 21 files changed, 63 insertions(+), 874 deletions(-)
 delete mode 100644 net/openvswitch/vport-geneve.c
 delete mode 100644 net/openvswitch/vport-gre.c
 delete mode 100644 net/openvswitch/vport-vxlan.c

-- 
2.55.0