在 2020/12/17 17:22, Steve Yang 写道:
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 &&
+ dev_info.max_mtu != UINT16_MAX &&
+ dev_info.max_rx_pktlen &&
+ 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)
/* 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;
+
Hi
I think the dev->data->mtu should be updated after configured
success. So the update in this position seems unreasonable.
'max_rx_pkt_len' is only used when jumbo_frame enabled, as follows:
struct rte_eth_rxmode {
.....
uint32_t max_rx_pkt_len; /**< Only used if JUMBO_FRAME enabled. */
/** Maximum allowed size of LRO aggregated packet. */
....};
So If DEV_RX_OFFLOAD_JUMBO_FRAME is set to rxmode.offload, driver should
configure mtu to hardware according to 'max_rx_pkt_len' and update
dev->data->mtu. This seems more reasonable. And some PMD drivers are
already doing this.
In addition, validity check for 'max_rx_pkt_len' in
rte_eth_dev_configure API may be error. It should be greater than
'RTE_ETHER_MTU + overhead_len'.
Because driver must enable DEV_RX_OFFLOAD_JUMBO_FRAME when user set mtu
with greater than 1500 by 'rte_eth_dev_set_mtu' API.
What do you think?
Thanks
Lijun Ou
/*
* If LRO is enabled, check that the maximum aggregated packet
* size is supported by the configured device.
