[dpdk-dev] [PATCH 3/6] net/bnxt: check for some error conditions in Tx path

[Ajit Khaparde <ajit.khaparde@broadcom.com>]

The HW can have limits on the minimum packet size it can support,
or the maximum number of segments it can support. Check for such
possibilities. Also check if we are going to have a 0 length buffer.

Fixes: 6eb3cc2294fd ("net/bnxt: add initial Tx code")
Signed-off-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Reviewed-by: Somnath Kotur <somnath.kotur@broadcom.com>
Signed-off-by: Sriharsha Basavapatna <sriharsha.basavapatna@broadcom.com>
---
 drivers/net/bnxt/bnxt_txr.c | 31 ++++++++++++++++++++++++++++++-
 drivers/net/bnxt/bnxt_txr.h |  2 ++
 2 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/drivers/net/bnxt/bnxt_txr.c b/drivers/net/bnxt/bnxt_txr.c
index 3a0d73af2..9684fb177 100644
--- a/drivers/net/bnxt/bnxt_txr.c
+++ b/drivers/net/bnxt/bnxt_txr.c
@@ -143,6 +143,33 @@ static uint16_t bnxt_start_xmit(struct rte_mbuf *tx_pkt,
 	tx_buf->mbuf = tx_pkt;
 	tx_buf->nr_bds = long_bd + tx_pkt->nb_segs;
 
+	/* Check if number of Tx descriptors is above HW limit */
+	if (unlikely(tx_buf->nr_bds > BNXT_MAX_TSO_SEGS)) {
+		PMD_DRV_LOG(ERR,
+			    "Num descriptors %d exceeds HW limit\n",
+			    tx_buf->nr_bds);
+		return -ENOSPC;
+	}
+
+	/* If packet length is less than minimum packet size, pad it */
+	if (unlikely(rte_pktmbuf_pkt_len(tx_pkt) < BNXT_MIN_PKT_SIZE)) {
+		uint8_t pad = BNXT_MIN_PKT_SIZE - rte_pktmbuf_pkt_len(tx_pkt);
+		char *seg = rte_pktmbuf_append(tx_pkt, pad);
+
+		if (!seg) {
+			PMD_DRV_LOG(ERR,
+				    "Failed to pad mbuf by %d bytes\n",
+				    pad);
+			return -ENOMEM;
+		}
+
+		/* Note: data_len, pkt len are updated in rte_pktmbuf_append */
+		memset(seg, 0, pad);
+	}
+
+	/* Check non zero data_len */
+	RTE_VERIFY(tx_pkt->data_len);
+
 	if (unlikely(bnxt_tx_avail(txr) < tx_buf->nr_bds))
 		return -ENOMEM;
 
@@ -203,6 +230,7 @@ static uint16_t bnxt_start_xmit(struct rte_mbuf *tx_pkt,
 			 */
 			txbd1->hdr_size = hdr_size >> 1;
 			txbd1->mss = tx_pkt->tso_segsz;
+			RTE_VERIFY(txbd1->mss);
 
 		} else if ((tx_pkt->ol_flags & PKT_TX_OIP_IIP_TCP_UDP_CKSUM) ==
 			   PKT_TX_OIP_IIP_TCP_UDP_CKSUM) {
@@ -285,8 +313,9 @@ static uint16_t bnxt_start_xmit(struct rte_mbuf *tx_pkt,
 	}
 
 	m_seg = tx_pkt->next;
-	/* i is set at the end of the if(long_bd) block */
 	while (m_seg) {
+		/* Check non zero data_len */
+		RTE_VERIFY(m_seg->data_len);
 		txr->tx_prod = RING_NEXT(txr->tx_ring_struct, txr->tx_prod);
 		tx_buf = &txr->tx_buf_ring[txr->tx_prod];
 
diff --git a/drivers/net/bnxt/bnxt_txr.h b/drivers/net/bnxt/bnxt_txr.h
index 7f3c7cdb0..f802d5080 100644
--- a/drivers/net/bnxt/bnxt_txr.h
+++ b/drivers/net/bnxt/bnxt_txr.h
@@ -10,6 +10,8 @@
 
 #define MAX_TX_RINGS	16
 #define BNXT_TX_PUSH_THRESH 92
+#define BNXT_MAX_TSO_SEGS	32
+#define BNXT_MIN_PKT_SIZE	52
 
 #define B_TX_DB(db, prod)	rte_write32((DB_KEY_TX | (prod)), db)
 
-- 
2.20.1 (Apple Git-117)