[PATCH v3] net/nfp: fix mtu settings

[Peng Zhang <peng.zhang@corigine.com>]

1.When the setting mtu is higher than flbufsz, the mtu doesn't work.
But it doesn't have any notice about this restrict.
2.add the min_mtu and max_mtu in the nfp_net_infos_get() to avoid
the setting mtu isn't in the range

This patch will add these restrict of nfp mtu.

Fixes: d4a27a3b092a ("nfp: add basic features")
Cc: stable@dpdk.org

Signed-off-by: Peng Zhang <peng.zhang@corigine.com>
Signed-off-by: Chaoyong He <chaoyong.he@corigine.com>
Signed-off-by: Louis Peens <louis.peens@corigine.com>
---
v3:
* git summary

v2:
* add the min_mtu and max_mtu in the nfp_net_infos_get()
---

 drivers/net/nfp/nfp_common.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/net/nfp/nfp_common.c b/drivers/net/nfp/nfp_common.c
index f8978e803a..4e48e33a63 100644
--- a/drivers/net/nfp/nfp_common.c
+++ b/drivers/net/nfp/nfp_common.c
@@ -693,6 +693,8 @@ nfp_net_infos_get(struct rte_eth_dev *dev, struct rte_eth_dev_info *dev_info)
 
 	hw = NFP_NET_DEV_PRIVATE_TO_HW(dev->data->dev_private);
 
+	dev_info->max_mtu = (uint16_t)hw->max_mtu;
+	dev_info->min_mtu = RTE_ETHER_MIN_MTU;
 	dev_info->max_rx_queues = (uint16_t)hw->max_rx_queues;
 	dev_info->max_tx_queues = (uint16_t)hw->max_tx_queues;
 	dev_info->min_rx_bufsize = RTE_ETHER_MIN_MTU;
@@ -956,6 +958,13 @@ nfp_net_dev_mtu_set(struct rte_eth_dev *dev, uint16_t mtu)
 		return -EBUSY;
 	}
 
+	/* the setting mtu is lower than flbufsz */
+	if (mtu > hw->flbufsz) {
+		PMD_DRV_LOG(ERR, "the setting mtu must be lower than current mbufsize of %d",
+			    hw->flbufsz);
+		return -ERANGE;
+	}
+
 	/* writing to configuration space */
 	nn_cfg_writel(hw, NFP_NET_CFG_MTU, mtu);
 
-- 
2.27.0