mbox series

[net,0/3] mlxsw: Handle changes to MTU in GRE tunnels

Message ID 20180322175335.26232-1-idosch@mellanox.com
Headers show
Series mlxsw: Handle changes to MTU in GRE tunnels | expand

Message

Ido Schimmel March 22, 2018, 5:53 p.m. UTC 
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(-)

Comments

David Miller March 23, 2018, 4:56 p.m. UTC | #1 
From: Ido Schimmel <idosch@mellanox.com>
Date: Thu, 22 Mar 2018 19:53:32 +0200

> 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.

Series applied, thanks.