On 1/25/2021 8:32 AM, Steve Yang wrote:
The MTU value should be updated to 'max_rx_pkt_len - overhead' no matter if the JUMBO FRAME offload enabled. If not update this MTU, use will get the wrong MTU info via some command. E.g.: 'show port info all' in testpmd tool.Actually, the 'max_rx_pkt_len' has been used for other purposes in many places now, even though the 'max_rx_pkt_len' is expected 'Only used if JUMBO_FRAME enabled'. For examples, 'max_rx_pkt_len' perhaps can be used as the 'rx_ctx.rxmax' in i40e. Fixes: bf0f90d92d30 ("ethdev: fix max Rx packet length check") Signed-off-by: Steve Yang <stevex.y...@intel.com> --- lib/librte_ethdev/rte_ethdev.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c index daf5f24f7e..42857e3b67 100644 --- a/lib/librte_ethdev/rte_ethdev.c +++ b/lib/librte_ethdev/rte_ethdev.c @@ -1421,10 +1421,6 @@ rte_eth_dev_configure(uint16_t port_id, uint16_t nb_rx_q, uint16_t nb_tx_q, ret = -EINVAL; goto rollback; } - - /* Scale the MTU size to adapt max_rx_pkt_len */ - dev->data->mtu = dev->data->dev_conf.rxmode.max_rx_pkt_len - - overhead_len; } else { uint16_t pktlen = dev_conf->rxmode.max_rx_pkt_len; if (pktlen < RTE_ETHER_MIN_MTU + overhead_len || @@ -1434,6 +1430,10 @@ rte_eth_dev_configure(uint16_t port_id, uint16_t nb_rx_q, uint16_t nb_tx_q, RTE_ETHER_MTU + overhead_len; }+ /* Scale the MTU size to adapt max_rx_pkt_len */+ dev->data->mtu = dev->data->dev_conf.rxmode.max_rx_pkt_len - + overhead_len; + /* * If LRO is enabled, check that the maximum aggregated packet * size is supported by the configured device.
This will cause 'max_rx_pkt_len' taken into account even 'JUMBO_FRAME' is not set, this is against the API documentation.
PMD can ignore the 'max_rx_pkt_len' when 'JUMBO_FRAME' is not set, so updating the 'max_rx_pkt_len' is relatively harmless, but updating 'MTU' can have affect.
Instead what do you think explicitly call 'rte_eth_dev_set_mtu()' in the testpmd when the MTU of the port needs to be changed because of "port config all max-pkt-len" command?
