[dpdk-dev] [PATCH v4 1/2] ethdev: fix MTU doesn't update when jumbo frame disabled

Steve Yang stevex.yang at intel.com
Mon Jan 25 09:32:01 CET 2021


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 at 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.
-- 
2.17.1



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