On 12/28/2020 2:51 PM, Andrew Rybchenko wrote:
On 12/17/20 12:22 PM, Steve Yang wrote:
If max rx packet length is smaller then MTU + Ether overhead, that will
drop all MTU size packets.
Update the MTU size according to the max rx packet and Ether overhead.
Fixes: 59d0ecdbf0e1 ("ethdev: MTU accessors")
Signed-off-by: Steve Yang <stevex.y...@intel.com>
---
lib/librte_ethdev/rte_ethdev.c | 21 ++++++++++++++++++---
1 file changed, 18 insertions(+), 3 deletions(-)
diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
index 17ddacc78d..ff6a1e675f 100644
--- a/lib/librte_ethdev/rte_ethdev.c
+++ b/lib/librte_ethdev/rte_ethdev.c
@@ -1292,6 +1292,7 @@ rte_eth_dev_configure(uint16_t port_id, uint16_t nb_rx_q,
uint16_t nb_tx_q,
struct rte_eth_dev *dev;
struct rte_eth_dev_info dev_info;
struct rte_eth_conf orig_conf;
+ uint16_t overhead_len;
int diag;
int ret;
@@ -1323,6 +1324,15 @@ rte_eth_dev_configure(uint16_t port_id, uint16_t nb_rx_q, uint16_t nb_tx_q,
if (ret != 0)
goto rollback;
+ /* Get the real Ethernet overhead length */
+ if (dev_info.max_mtu &&
First of all I'm not sure that we need to handle 0 value
separately. Or it should be checked separately and trigger
an error since it is a driver mis-behaviour.
Agree. Most probably we can drop it, "dev_info.max_mtu != UINT16_MAX" covers the
case driver doesn't provide any value.
If kept, it should be compared vs 0 explicitly in accordance
with DPDK coding style.
+ dev_info.max_mtu != UINT16_MAX &&
+ dev_info.max_rx_pktlen &&
It should be compared vs 0 explicitly in accordance
with DPDK coding style.
+ dev_info.max_rx_pktlen > dev_info.max_mtu)
+ overhead_len = dev_info.max_rx_pktlen - dev_info.max_mtu;
+ else
+ overhead_len = RTE_ETHER_HDR_LEN + RTE_ETHER_CRC_LEN;
+
/* If number of queues specified by application for both Rx and Tx is
* zero, use driver preferred values. This cannot be done individually
* as it is valid for either Tx or Rx (but not both) to be zero.
@@ -1410,13 +1420,18 @@ rte_eth_dev_configure(uint16_t port_id, uint16_t
nb_rx_q, uint16_t nb_tx_q,
goto rollback;
}
} else {
- if (dev_conf->rxmode.max_rx_pkt_len < RTE_ETHER_MIN_LEN ||
- dev_conf->rxmode.max_rx_pkt_len > RTE_ETHER_MAX_LEN)
+ uint16_t pktlen = dev_conf->rxmode.max_rx_pkt_len;
+ if (pktlen < RTE_ETHER_MIN_MTU + overhead_len ||
+ pktlen > RTE_ETHER_MTU + overhead_len)
Alignment looks misleading. Either two tabs or just 4 spaces.
/* Use default value */
dev->data->dev_conf.rxmode.max_rx_pkt_len =
- RTE_ETHER_MAX_LEN;
+ 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;
+
Is it expected side effect that re-configure always resets
previously set MTU. I.e.:
configure -> set_mtu -> start -> stop -> re-configure
and set MTU is lost.
This is the problem of two APIs updating same/related values, when device
re-configure with a given 'max_rx_pkt_len', can we know if the intentions is
update to the value to new provided 'max_rx_pkt_len' or not?
For this case if user want to keep the MTU value, can read the MTU from device
first and set 'max_rx_pkt_len' according it.
And we can reduce to updating the MTU in the configure() only when JUMBO frame
offload is requested, that should be when the 'max_rx_pkt_len' is valid only.
/*
* If LRO is enabled, check that the maximum aggregated packet
* size is supported by the configured device.
