[dpdk-dev] [PATCH] net/bnxt: fix cp ring size calculation

[Lance Richardson]

The size of the receive completion ring should be recalculated
when MTU is increased to a size that requires scattered receive
or when LRO is enabled. Move logic for this calculation from
the ring configuration path to the device start path.
   - Made size calculation dependent only on scattered_rx
     status.
   - Moved calculation of scattered_rx up in the initialization
     sequence.
   - Made LRO offload status part of scattered_rx calculation.

When the completion ring size is too small, completion overflows
can occur causing the ring to be disabled in hardware.

Fixes: 04067844a3e9 ("net/bnxt: reduce CQ queue size without aggregation ring")
Cc: stable at dpdk.org
Signed-off-by: Lance Richardson <lance.richardson at broadcom.com>
Reviewed-by: Ajit Kumar Khaparde <ajit.khaparde at broadcom.com>
---
 drivers/net/bnxt/bnxt_ethdev.c |  6 +++++-
 drivers/net/bnxt/bnxt_rxr.c    | 15 +--------------
 2 files changed, 6 insertions(+), 15 deletions(-)

diff --git a/drivers/net/bnxt/bnxt_ethdev.c b/drivers/net/bnxt/bnxt_ethdev.c
index ec88cb0046..ca779726ec 100644
--- a/drivers/net/bnxt/bnxt_ethdev.c
+++ b/drivers/net/bnxt/bnxt_ethdev.c
@@ -1143,6 +1143,9 @@ static int bnxt_scattered_rx(struct rte_eth_dev *eth_dev)
 	if (eth_dev->data->dev_conf.rxmode.offloads & DEV_RX_OFFLOAD_SCATTER)
 		return 1;
 
+	if (eth_dev->data->dev_conf.rxmode.offloads & DEV_RX_OFFLOAD_TCP_LRO)
+		return 1;
+
 	for (i = 0; i < eth_dev->data->nb_rx_queues; i++) {
 		struct bnxt_rx_queue *rxq = eth_dev->data->rx_queues[i];
 
@@ -1418,11 +1421,12 @@ static int bnxt_dev_start_op(struct rte_eth_dev *eth_dev)
 
 	bnxt_enable_int(bp);
 
+	eth_dev->data->scattered_rx = bnxt_scattered_rx(eth_dev);
+
 	rc = bnxt_start_nic(bp);
 	if (rc)
 		goto error;
 
-	eth_dev->data->scattered_rx = bnxt_scattered_rx(eth_dev);
 	eth_dev->data->dev_started = 1;
 
 	bnxt_link_update_op(eth_dev, 1);
diff --git a/drivers/net/bnxt/bnxt_rxr.c b/drivers/net/bnxt/bnxt_rxr.c
index 8c2781c968..4674f7cea2 100644
--- a/drivers/net/bnxt/bnxt_rxr.c
+++ b/drivers/net/bnxt/bnxt_rxr.c
@@ -1116,12 +1116,9 @@ void bnxt_free_rx_rings(struct bnxt *bp)
 
 int bnxt_init_rx_ring_struct(struct bnxt_rx_queue *rxq, unsigned int socket_id)
 {
-	struct rte_eth_dev *eth_dev = rxq->bp->eth_dev;
-	struct rte_eth_rxmode *rxmode;
 	struct bnxt_cp_ring_info *cpr;
 	struct bnxt_rx_ring_info *rxr;
 	struct bnxt_ring *ring;
-	bool use_agg_ring;
 
 	rxq->rx_buf_size = BNXT_MAX_PKT_LEN + sizeof(struct rte_mbuf);
 
@@ -1164,19 +1161,9 @@ int bnxt_init_rx_ring_struct(struct bnxt_rx_queue *rxq, unsigned int socket_id)
 		return -ENOMEM;
 	cpr->cp_ring_struct = ring;
 
-	rxmode = &eth_dev->data->dev_conf.rxmode;
-	use_agg_ring = (rxmode->offloads & DEV_RX_OFFLOAD_SCATTER) ||
-		       (rxmode->offloads & DEV_RX_OFFLOAD_TCP_LRO) ||
-		       (rxmode->max_rx_pkt_len >
-			 (uint32_t)(rte_pktmbuf_data_room_size(rxq->mb_pool) -
-				    RTE_PKTMBUF_HEADROOM));
-
 	/* Allocate two completion slots per entry in desc ring. */
 	ring->ring_size = rxr->rx_ring_struct->ring_size * 2;
-
-	/* Allocate additional slots if aggregation ring is in use. */
-	if (use_agg_ring)
-		ring->ring_size *= AGG_RING_SIZE_FACTOR;
+	ring->ring_size *= AGG_RING_SIZE_FACTOR;
 
 	ring->ring_size = rte_align32pow2(ring->ring_size);
 	ring->ring_mask = ring->ring_size - 1;
-- 
2.25.1