[dpdk-dev] [PATCH v2 09/17] net/bnxt: fix max rings computation

[Ajit Khaparde <ajitkhaparde@gmail.com>]

From: Sriharsha Basavapatna <sriharsha.basavapatna@broadcom.com>

The current max_rings computation does not take into account the case
when max_nq_rings is <= num_async_cpr. This results in a wrong value
like 0, when max_nq_rings is 1. Fix this by subtracting num_async_cpr
only when max_cp_rings > num_async_cpr.

Apart from this, the entire logic is currently spread across a few
macros, making it hard to read and debug this code. Move this code
into an inline function.

max_msix is not used in the max_rings calculation.
Apparently the max_msix field returned in HWRM_RESC_QCAPS is only
valid for Thor and newer chips. On Wh+ it will be equal to min_compl_rings.
Also, when a function reset is performed on an application quit, FW
will not reset the VF resource pool as per design.
This can lead to a strange condition wherein the max_msix field
on Wh+ keeps changing on each application re-load thereby throwing
throwing off the max_rings computation.

Fixes: f03e66cb64ce ("net/bnxt: limit queue count for NS3/Stingray devices")
Cc: stable@dpdk.org

Signed-off-by: Sriharsha Basavapatna <sriharsha.basavapatna@broadcom.com>
Signed-off-by: Somnath Kotur <somnath.kotur@broadcom.com>
Reviewed-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
---
 drivers/net/bnxt/bnxt.h        | 41 +++++++++++++++++++++++-----------
 drivers/net/bnxt/bnxt_ethdev.c |  2 +-
 drivers/net/bnxt/bnxt_rxq.c    |  7 +++---
 drivers/net/bnxt/bnxt_txq.c    |  2 +-
 4 files changed, 34 insertions(+), 18 deletions(-)

diff --git a/drivers/net/bnxt/bnxt.h b/drivers/net/bnxt/bnxt.h
index 9c1c87489..bc0935272 100644
--- a/drivers/net/bnxt/bnxt.h
+++ b/drivers/net/bnxt/bnxt.h
@@ -752,19 +752,6 @@ struct bnxt {
 	uint16_t		max_tx_rings;
 	uint16_t		max_rx_rings;
 #define MAX_STINGRAY_RINGS		128U
-/* For sake of symmetry, max Tx rings == max Rx rings, one stat ctx for each */
-#define BNXT_MAX_RX_RINGS(bp) \
-	(BNXT_STINGRAY(bp) ? RTE_MIN(RTE_MIN(bp->max_rx_rings / 2U, \
-					     MAX_STINGRAY_RINGS), \
-				     bp->max_stat_ctx / 2U) : \
-				RTE_MIN(bp->max_rx_rings / 2U, \
-					bp->max_stat_ctx / 2U))
-#define BNXT_MAX_TX_RINGS(bp) \
-	(RTE_MIN((bp)->max_tx_rings, BNXT_MAX_RX_RINGS(bp)))
-
-#define BNXT_MAX_RINGS(bp) \
-	(RTE_MIN((((bp)->max_cp_rings - BNXT_NUM_ASYNC_CPR(bp)) / 2U), \
-		 BNXT_MAX_TX_RINGS(bp)))
 
 #define BNXT_MAX_VF_REP_RINGS	8
 
@@ -822,6 +809,34 @@ struct bnxt {
 	uint16_t		tx_cfa_action;
 };
 
+static
+inline uint16_t bnxt_max_rings(struct bnxt *bp)
+{
+	uint16_t max_tx_rings = bp->max_tx_rings;
+	uint16_t max_rx_rings = bp->max_rx_rings;
+	uint16_t max_cp_rings = bp->max_cp_rings;
+	uint16_t max_rings;
+
+	/* For the sake of symmetry:
+	 * max Tx rings == max Rx rings, one stat ctx for each.
+	 */
+	if (BNXT_STINGRAY(bp)) {
+		max_rx_rings = RTE_MIN(RTE_MIN(max_rx_rings / 2U,
+					       MAX_STINGRAY_RINGS),
+				       bp->max_stat_ctx / 2U);
+	} else {
+		max_rx_rings = RTE_MIN(max_rx_rings / 2U,
+				       bp->max_stat_ctx / 2U);
+	}
+
+	max_tx_rings = RTE_MIN(max_tx_rings, max_rx_rings);
+	if (max_cp_rings > BNXT_NUM_ASYNC_CPR(bp))
+		max_cp_rings -= BNXT_NUM_ASYNC_CPR(bp);
+	max_rings = RTE_MIN(max_cp_rings / 2U, max_tx_rings);
+
+	return max_rings;
+}
+
 #define BNXT_FC_TIMER	1 /* Timer freq in Sec Flow Counters */
 
 /**
diff --git a/drivers/net/bnxt/bnxt_ethdev.c b/drivers/net/bnxt/bnxt_ethdev.c
index 0b14ca234..bf8963577 100644
--- a/drivers/net/bnxt/bnxt_ethdev.c
+++ b/drivers/net/bnxt/bnxt_ethdev.c
@@ -920,7 +920,7 @@ static int bnxt_dev_info_get_op(struct rte_eth_dev *eth_dev,
 	if (BNXT_PF(bp))
 		dev_info->max_vfs = pdev->max_vfs;
 
-	max_rx_rings = BNXT_MAX_RINGS(bp);
+	max_rx_rings = bnxt_max_rings(bp);
 	/* For the sake of symmetry, max_rx_queues = max_tx_queues */
 	dev_info->max_rx_queues = max_rx_rings;
 	dev_info->max_tx_queues = max_rx_rings;
diff --git a/drivers/net/bnxt/bnxt_rxq.c b/drivers/net/bnxt/bnxt_rxq.c
index 328cc994d..19e11e47b 100644
--- a/drivers/net/bnxt/bnxt_rxq.c
+++ b/drivers/net/bnxt/bnxt_rxq.c
@@ -311,7 +311,7 @@ int bnxt_rx_queue_setup_op(struct rte_eth_dev *eth_dev,
 	if (rc)
 		return rc;
 
-	if (queue_idx >= BNXT_MAX_RINGS(bp)) {
+	if (queue_idx >= bnxt_max_rings(bp)) {
 		PMD_DRV_LOG(ERR,
 			"Cannot create Rx ring %d. Only %d rings available\n",
 			queue_idx, bp->max_rx_rings);
@@ -364,8 +364,9 @@ int bnxt_rx_queue_setup_op(struct rte_eth_dev *eth_dev,
 
 	eth_dev->data->rx_queues[queue_idx] = rxq;
 	/* Allocate RX ring hardware descriptors */
-	if (bnxt_alloc_rings(bp, queue_idx, NULL, rxq, rxq->cp_ring, NULL,
-			     "rxr")) {
+	rc = bnxt_alloc_rings(bp, queue_idx, NULL, rxq, rxq->cp_ring, NULL,
+			     "rxr");
+	if (rc) {
 		PMD_DRV_LOG(ERR,
 			    "ring_dma_zone_reserve for rx_ring failed!\n");
 		goto err;
diff --git a/drivers/net/bnxt/bnxt_txq.c b/drivers/net/bnxt/bnxt_txq.c
index c9792a2af..99a31cef2 100644
--- a/drivers/net/bnxt/bnxt_txq.c
+++ b/drivers/net/bnxt/bnxt_txq.c
@@ -98,7 +98,7 @@ int bnxt_tx_queue_setup_op(struct rte_eth_dev *eth_dev,
 	if (rc)
 		return rc;
 
-	if (queue_idx >= BNXT_MAX_RINGS(bp)) {
+	if (queue_idx >= bnxt_max_rings(bp)) {
 		PMD_DRV_LOG(ERR,
 			"Cannot create Tx ring %d. Only %d rings available\n",
 			queue_idx, bp->max_tx_rings);
-- 
2.21.1 (Apple Git-122.3)