net/bnxt: fix set MTU

There is no need to update bnxt_hwrm_vnic_plcmode_cfg if new MTU is
not greater than the max data the mbuf can accommodate.

Fixes: daef48efe5e5 ("net/bnxt: support set MTU")
Cc: stable@dpdk.org
Signed-off-by: Ajit Khaparde <ajit.khaparde@broadcom.com>

diff --git a/drivers/net/bnxt/bnxt_ethdev.c b/drivers/net/bnxt/bnxt_ethdev.c
index 7fa69b4..896e2d2 100644 (file)
--- a/drivers/net/bnxt/bnxt_ethdev.c
+++ b/drivers/net/bnxt/bnxt_ethdev.c
@@ -1582,6 +1582,7 @@ static int bnxt_mtu_set_op(struct rte_eth_dev *eth_dev, uint16_t new_mtu)
 
        for (i = 0; i < bp->nr_vnics; i++) {
                struct bnxt_vnic_info *vnic = &bp->vnic_info[i];
+               uint16_t size = 0;
 
                vnic->mru = bp->eth_dev->data->mtu + ETHER_HDR_LEN +
                                        ETHER_CRC_LEN + VLAN_TAG_SIZE * 2;
@@ -1589,9 +1590,14 @@ static int bnxt_mtu_set_op(struct rte_eth_dev *eth_dev, uint16_t new_mtu)
                if (rc)
                        break;
 
-               rc = bnxt_hwrm_vnic_plcmode_cfg(bp, vnic);
-               if (rc)
-                       return rc;
+               size = rte_pktmbuf_data_room_size(bp->rx_queues[0]->mb_pool);
+               size -= RTE_PKTMBUF_HEADROOM;
+
+               if (size < new_mtu) {
+                       rc = bnxt_hwrm_vnic_plcmode_cfg(bp, vnic);
+                       if (rc)
+                               return rc;
+               }
        }
 
        return rc;