Re: [dpdk-dev] [PATCH v6 2/2] librte_ethdev: fix MTU size exceeds max rx packet length

Update the MTU size according to the max rx packet and Ether overhead.

Fixes: 59d0ecdbf0e1 ("ethdev: MTU accessors")

Signed-off-by: SteveX Yang <redacted>
---
 lib/librte_ethdev/rte_ethdev.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
index b12bb3854..17f1c33ac 100644
--- a/lib/librte_ethdev/rte_ethdev.c
+++ b/lib/librte_ethdev/rte_ethdev.c

@@ -1290,6 +1290,8 @@ 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;
+	uint16_t max_rx_pktlen;
 	int diag;
 	int ret;

@@ -1415,6 +1417,18 @@ rte_eth_dev_configure(uint16_t port_id, uint16_t nb_rx_q, uint16_t nb_tx_q,
 							RTE_ETHER_MAX_LEN;
 	}

+	/*
+	 * Update MTU value if MTU + OVERHEAD exceeds the max_rx_pkt_len
+	 */
+	max_rx_pktlen = dev->data->dev_conf.rxmode.max_rx_pkt_len;
+	if (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 (max_rx_pktlen < dev->data->mtu + overhead_len)