[dpdk-stable] [PATCH v2 2/2] examples/kni: fix MTU change to setup Tx queue

[Rasesh Mody]

This patch adds a fix to setup Tx queue when changing KNI interface MTU.
It ensures device can safely start txq post MTU change operation.

Fixes: fc9ee41b7016 ("examples/kni: convert to new ethdev offloads API")
Cc: stable at dpdk.org

Signed-off-by: Rasesh Mody <rmody at marvell.com>
---
 examples/kni/main.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/examples/kni/main.c b/examples/kni/main.c
index 6b4ab3b5b..7a927a50c 100644
--- a/examples/kni/main.c
+++ b/examples/kni/main.c
@@ -774,9 +774,11 @@ kni_change_mtu(uint16_t port_id, unsigned int new_mtu)
 {
 	int ret;
 	uint16_t nb_rxd = NB_RXD;
+	uint16_t nb_txd = NB_TXD;
 	struct rte_eth_conf conf;
 	struct rte_eth_dev_info dev_info;
 	struct rte_eth_rxconf rxq_conf;
+	struct rte_eth_txconf txq_conf;
 
 	if (!rte_eth_dev_is_valid_port(port_id)) {
 		RTE_LOG(ERR, APP, "Invalid port id %d\n", port_id);
@@ -804,7 +806,7 @@ kni_change_mtu(uint16_t port_id, unsigned int new_mtu)
 		return ret;
 	}
 
-	ret = rte_eth_dev_adjust_nb_rx_tx_desc(port_id, &nb_rxd, NULL);
+	ret = rte_eth_dev_adjust_nb_rx_tx_desc(port_id, &nb_rxd, &nb_txd);
 	if (ret < 0)
 		rte_exit(EXIT_FAILURE, "Could not adjust number of descriptors "
 				"for port%u (%d)\n", (unsigned int)port_id,
@@ -829,6 +831,16 @@ kni_change_mtu(uint16_t port_id, unsigned int new_mtu)
 		return ret;
 	}
 
+	txq_conf = dev_info.default_txconf;
+	txq_conf.offloads = conf.txmode.offloads;
+	ret = rte_eth_tx_queue_setup(port_id, 0, nb_txd,
+		rte_eth_dev_socket_id(port_id), &txq_conf);
+	if (ret < 0) {
+		RTE_LOG(ERR, APP, "Fail to setup Tx queue of port %d\n",
+				port_id);
+		return ret;
+	}
+
 	/* Restart specific port */
 	ret = rte_eth_dev_start(port_id);
 	if (ret < 0) {
-- 
2.18.0