iavf: fix netdev->max_mtu to respect actual hardware limit

[ Upstream commit b84852170153671bb0fa6737a6e48370addd8e1a ]

iavf sets LIBIE_MAX_MTU as netdev->max_mtu, ignoring vf_res->max_mtu
from PF [1]. This allows setting an MTU beyond the actual hardware
limit, causing TX queue timeouts [2].

Set correct netdev->max_mtu using vf_res->max_mtu from the PF.

Note that currently PF drivers such as ice/i40e set the frame size in
vf_res->max_mtu, not MTU. Convert vf_res->max_mtu to MTU before setting
netdev->max_mtu.

[1]
 # ip -j -d link show $DEV | jq '.[0].max_mtu'
 16356

[2]
 iavf 0000:00:05.0 enp0s5: NETDEV WATCHDOG: CPU: 1: transmit queue 0 timed out 5692 ms
 iavf 0000:00:05.0 enp0s5: NIC Link is Up Speed is 10 Gbps Full Duplex
 iavf 0000:00:05.0 enp0s5: NETDEV WATCHDOG: CPU: 6: transmit queue 3 timed out 5312 ms
 iavf 0000:00:05.0 enp0s5: NIC Link is Up Speed is 10 Gbps Full Duplex
 ...

Fixes: 5fa4caff59f2 ("iavf: switch to Page Pool")
Signed-off-by: Kohei Enju <kohei@enjuk.jp>
Reviewed-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Tested-by: Rafal Romanowski <rafal.romanowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

0 files changed, 0 insertions, 0 deletions