[v4,1/2] ethdev: fix MTU doesn't update when jumbo frame disabled
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Commit Message
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.yang@intel.com>
---
lib/librte_ethdev/rte_ethdev.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
Comments
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.yang@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?
@@ -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.