[dpdk-stable] patch 'net/bnxt: fix scalar Tx completion handling' has been queued to stable release 20.11.3

[luca.boccassi at gmail.com]

Hi,

FYI, your patch has been queued to stable release 20.11.3

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 07/14/21. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Queued patches are on a temporary branch at:
https://github.com/bluca/dpdk-stable

This queued commit can be viewed at:
https://github.com/bluca/dpdk-stable/commit/ea63b9f5ca7c1860f52cc5154059a7988a2777a3

Thanks.

Luca Boccassi

---
>From ea63b9f5ca7c1860f52cc5154059a7988a2777a3 Mon Sep 17 00:00:00 2001
From: Lance Richardson <lance.richardson at broadcom.com>
Date: Wed, 16 Jun 2021 13:55:22 -0400
Subject: [PATCH] net/bnxt: fix scalar Tx completion handling

[ upstream commit 2b5a36f4df0c00407117ed6f8f9444dd943b4f4c ]

Preserve the raw (unmasked) transmit completion ring
consumer index.

Remove cache prefetches that have no measurable performance
benefit.

Fixes: c7de4195cc4c ("net/bnxt: modify ring index logic")

Signed-off-by: Lance Richardson <lance.richardson at broadcom.com>
Reviewed-by: Ajit Khaparde <ajit.khaparde at broadcom.com>
---
 drivers/net/bnxt/bnxt_txr.c | 24 +++++++++++-------------
 1 file changed, 11 insertions(+), 13 deletions(-)

diff --git a/drivers/net/bnxt/bnxt_txr.c b/drivers/net/bnxt/bnxt_txr.c
index 0cf6ece786..412bc59f3b 100644
--- a/drivers/net/bnxt/bnxt_txr.c
+++ b/drivers/net/bnxt/bnxt_txr.c
@@ -427,30 +427,26 @@ static void bnxt_tx_cmp(struct bnxt_tx_queue *txq, int nr_pkts)
 
 static int bnxt_handle_tx_cp(struct bnxt_tx_queue *txq)
 {
+	uint32_t nb_tx_pkts = 0, cons, ring_mask, opaque;
 	struct bnxt_cp_ring_info *cpr = txq->cp_ring;
 	uint32_t raw_cons = cpr->cp_raw_cons;
-	uint32_t cons;
-	uint32_t nb_tx_pkts = 0;
+	struct bnxt_ring *cp_ring_struct;
 	struct tx_cmpl *txcmp;
-	struct cmpl_base *cp_desc_ring = cpr->cp_desc_ring;
-	struct bnxt_ring *cp_ring_struct = cpr->cp_ring_struct;
-	uint32_t ring_mask = cp_ring_struct->ring_mask;
-	uint32_t opaque = 0;
 
 	if (bnxt_tx_bds_in_hw(txq) < txq->tx_free_thresh)
 		return 0;
 
+	cp_ring_struct = cpr->cp_ring_struct;
+	ring_mask = cp_ring_struct->ring_mask;
+
 	do {
 		cons = RING_CMPL(ring_mask, raw_cons);
 		txcmp = (struct tx_cmpl *)&cpr->cp_desc_ring[cons];
-		rte_prefetch_non_temporal(&cp_desc_ring[(cons + 2) &
-							ring_mask]);
 
-		if (!CMPL_VALID(txcmp, cpr->valid))
+		if (!CMP_VALID(txcmp, raw_cons, cp_ring_struct))
 			break;
-		opaque = rte_cpu_to_le_32(txcmp->opaque);
-		NEXT_CMPL(cpr, cons, cpr->valid, 1);
-		rte_prefetch0(&cp_desc_ring[cons]);
+
+		opaque = rte_le_to_cpu_32(txcmp->opaque);
 
 		if (CMP_TYPE(txcmp) == TX_CMPL_TYPE_TX_L2)
 			nb_tx_pkts += opaque;
@@ -458,9 +454,11 @@ static int bnxt_handle_tx_cp(struct bnxt_tx_queue *txq)
 			RTE_LOG_DP(ERR, PMD,
 					"Unhandled CMP type %02x\n",
 					CMP_TYPE(txcmp));
-		raw_cons = cons;
+		raw_cons = NEXT_RAW_CMP(raw_cons);
 	} while (nb_tx_pkts < ring_mask);
 
+	cpr->valid = !!(raw_cons & cp_ring_struct->ring_size);
+
 	if (nb_tx_pkts) {
 		if (txq->offloads & DEV_TX_OFFLOAD_MBUF_FAST_FREE)
 			bnxt_tx_cmp_fast(txq, nb_tx_pkts);
-- 
2.30.2

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2021-07-12 13:41:41.250783611 +0100
+++ 0090-net-bnxt-fix-scalar-Tx-completion-handling.patch	2021-07-12 13:41:36.762128276 +0100
@@ -1 +1 @@
-From 2b5a36f4df0c00407117ed6f8f9444dd943b4f4c Mon Sep 17 00:00:00 2001
+From ea63b9f5ca7c1860f52cc5154059a7988a2777a3 Mon Sep 17 00:00:00 2001
@@ -5,0 +6,2 @@
+[ upstream commit 2b5a36f4df0c00407117ed6f8f9444dd943b4f4c ]
+
@@ -13 +14,0 @@
-Cc: stable at dpdk.org
@@ -22 +23 @@
-index 27459960de..54eaab34a0 100644
+index 0cf6ece786..412bc59f3b 100644
@@ -25 +26 @@
-@@ -444,30 +444,26 @@ static void bnxt_tx_cmp(struct bnxt_tx_queue *txq, int nr_pkts)
+@@ -427,30 +427,26 @@ static void bnxt_tx_cmp(struct bnxt_tx_queue *txq, int nr_pkts)
@@ -64 +65 @@
-@@ -475,9 +471,11 @@ static int bnxt_handle_tx_cp(struct bnxt_tx_queue *txq)
+@@ -458,9 +454,11 @@ static int bnxt_handle_tx_cp(struct bnxt_tx_queue *txq)