[PATCH v2] net/ice: fix scalar Rx and Tx path segment

[Mingjin Ye <mingjinx.ye@intel.com>]

CRC is stripped by the hardware in the scattered Rx path. If the last
buffer packet length is '0', the scalar Tx path would send empty buffer
that causes the Tx queue to overflow.

This patch adds a judgment for the last buffer length to fix this issue,
so that it would free the mbuf associated to the last one if the last
buffer is empty.

Fixes: 6eac0b7fde95 ("net/ice: support advance Rx/Tx")
Cc: stable@dpdk.org

Signed-off-by: Mingjin Ye <mingjinx.ye@intel.com>

v2:
	* Fix log level in ice_rxtx.c source file.
---
 drivers/net/ice/ice_rxtx.c | 53 ++++++++++++++++++++++++++++++++++++--
 1 file changed, 51 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ice/ice_rxtx.c b/drivers/net/ice/ice_rxtx.c
index 0a2b0376ac..b181f66aad 100644
--- a/drivers/net/ice/ice_rxtx.c
+++ b/drivers/net/ice/ice_rxtx.c
@@ -2111,6 +2111,10 @@ ice_recv_scattered_pkts(void *rx_queue,
 			} else
 				rxm->data_len = (uint16_t)(rx_packet_len -
 							   RTE_ETHER_CRC_LEN);
+		} else if (rx_packet_len == 0) {
+			rte_pktmbuf_free_seg(rxm);
+			first_seg->nb_segs--;
+			last_seg->next = NULL;
 		}
 
 		first_seg->port = rxq->port_id;
@@ -2903,6 +2907,35 @@ ice_calc_pkt_desc(struct rte_mbuf *tx_pkt)
 	return count;
 }
 
+/*Check the number of valid mbufs and free the invalid mbufs*/
+static inline uint16_t
+ice_check_mbuf(struct rte_mbuf *tx_pkt)
+{
+	struct rte_mbuf *txd = tx_pkt;
+	struct rte_mbuf *txd_removal = NULL;
+	struct rte_mbuf *txd_pre = NULL;
+	uint16_t count = 0;
+	uint16_t removal = 0;
+
+	while (txd != NULL) {
+		if (removal == 1 || txd->data_len == 0) {
+			txd_removal = txd;
+			txd = txd->next;
+			if (removal == 0) {
+				removal = 1;
+				txd_pre->next = NULL;
+			}
+			rte_pktmbuf_free_seg(txd_removal);
+		} else {
+			++count;
+			txd_pre = txd;
+			txd = txd->next;
+		}
+	}
+
+	return count;
+}
+
 uint16_t
 ice_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 {
@@ -2960,11 +2993,27 @@ ice_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 		 * the mbuf data size exceeds max data size that hw allows
 		 * per tx desc.
 		 */
-		if (ol_flags & RTE_MBUF_F_TX_TCP_SEG)
+		if (ol_flags & RTE_MBUF_F_TX_TCP_SEG) {
 			nb_used = (uint16_t)(ice_calc_pkt_desc(tx_pkt) +
 					     nb_ctx);
-		else
+		} else {
+			nb_used = ice_check_mbuf(tx_pkt);
+			if (nb_used == 0) {
+				PMD_TX_LOG(ERR,
+				"Check packets is empty "
+				"(port=%d queue=%d)\n",
+				txq->port_id, txq->queue_id);
+				continue;
+			} else if (nb_used < tx_pkt->nb_segs) {
+				PMD_TX_LOG(DEBUG,
+				"Check packets valid num ="
+				"%4u total num = %4u (port=%d queue=%d)\n",
+				nb_used, tx_pkt->nb_segs, txq->port_id, txq->queue_id);
+				tx_pkt->nb_segs = nb_used;
+			}
 			nb_used = (uint16_t)(tx_pkt->nb_segs + nb_ctx);
+		}
+
 		tx_last = (uint16_t)(tx_id + nb_used - 1);
 
 		/* Circular ring */
-- 
2.34.1