Petr says:
When offloading GRE tunnels, the MTU setting is kept fixed after the
initial offload even as the slow-path configuration changed. Worse: the
offloaded MTU setting is actually just a transient value set at the time
of NETDEV_REGISTER of the tunnel. As of commit ffc2b6ee4174 ("ip_gre:
fix IFLA_MTU ignored on NEWLINK"), that transient value is zero, and
unless there's e.g. a VRF migration that prompts re-offload, it stays at
zero, and all GRE packets end up trapping.
Thus, in patch #1, change the way the MTU is changed post-registration,
so that the full event protocol is observed. That way the drivers get to
see the change and have a chance to react.
In the remaining two patches, implement support for MTU change in mlxsw
driver.
Petr Machata (3):
ip_tunnel: Emit events for post-register MTU changes
mlxsw: spectrum_router: Move mlxsw_sp_rif_ipip_lb_op()
mlxsw: spectrum_router: Handle MTU change of GRE netdevs
.../net/ethernet/mellanox/mlxsw/spectrum_router.c | 78 ++++++++++++++--------
net/ipv4/ip_tunnel.c | 26 ++++++--
2 files changed, 72 insertions(+), 32 deletions(-)
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2.14.3
