[dpdk-stable] patch 'net/mlx5: fix timestamp initialization on empty clock queue' 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 08/05/21. 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/f46e2c750ac23a6c6f53b64c99c76a6c02111971

Thanks.

Luca Boccassi

---
>From f46e2c750ac23a6c6f53b64c99c76a6c02111971 Mon Sep 17 00:00:00 2001
From: Viacheslav Ovsiienko <viacheslavo at nvidia.com>
Date: Wed, 28 Jul 2021 17:23:35 +0300
Subject: [PATCH] net/mlx5: fix timestamp initialization on empty clock queue

[ upstream commit dab07e489cd5be47a017e0b8558b3fe3ee03b979 ]

The committing completions by clock queue might be delayed
after queue initialization is done and the only Clock Queue
completion entry (CQE) might keep the invalid status till
the CQE first update happens.

The mlx5_txpp_update_timestamp() wrongly recognized invalid
status as error and reported about lost synchronization.

The patch recognizes the invalid status as "not updated yet"
and accurate scheduling initialization routine waits till
CQE first update happens.

Some collateral typos in comment are fixed as well.

Fixes: 77522be0a56d ("net/mlx5: introduce clock queue service routine")

Signed-off-by: Viacheslav Ovsiienko <viacheslavo at nvidia.com>
---
 drivers/net/mlx5/mlx5_txpp.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/drivers/net/mlx5/mlx5_txpp.c b/drivers/net/mlx5/mlx5_txpp.c
index 72b0690913..cf11048160 100644
--- a/drivers/net/mlx5/mlx5_txpp.c
+++ b/drivers/net/mlx5/mlx5_txpp.c
@@ -676,8 +676,8 @@ mlx5_atomic_read_cqe(rte_int128_t *from, rte_int128_t *ts)
 {
 	/*
 	 * The only CQE of Clock Queue is being continuously
-	 * update by hardware with soecified rate. We have to
-	 * read timestump and WQE completion index atomically.
+	 * updated by hardware with specified rate. We must
+	 * read timestamp and WQE completion index atomically.
 	 */
 #if defined(RTE_ARCH_X86_64)
 	rte_int128_t src;
@@ -738,15 +738,24 @@ mlx5_txpp_update_timestamp(struct mlx5_dev_ctx_shared *sh)
 	} to;
 	uint64_t ts;
 	uint16_t ci;
+	uint8_t opcode;
 
 	static_assert(sizeof(struct mlx5_cqe_ts) == sizeof(rte_int128_t),
 		      "Wrong timestamp CQE part size");
 	mlx5_atomic_read_cqe((rte_int128_t *)&cqe->timestamp, &to.u128);
-	if (to.cts.op_own >> 4) {
-		DRV_LOG(DEBUG, "Clock Queue error sync lost.");
-		__atomic_fetch_add(&sh->txpp.err_clock_queue,
+	opcode = MLX5_CQE_OPCODE(to.cts.op_own);
+	if (opcode) {
+		if (opcode != MLX5_CQE_INVALID) {
+			/*
+			 * Commit the error state if and only if
+			 * we have got at least one actual completion.
+			 */
+			DRV_LOG(DEBUG,
+				"Clock Queue error sync lost (%X).", opcode);
+				__atomic_fetch_add(&sh->txpp.err_clock_queue,
 				   1, __ATOMIC_RELAXED);
-		sh->txpp.sync_lost = 1;
+			sh->txpp.sync_lost = 1;
+		}
 		return;
 	}
 	ci = rte_be_to_cpu_16(to.cts.wqe_counter);
-- 
2.30.2

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2021-08-03 12:35:08.701055993 +0100
+++ 0011-net-mlx5-fix-timestamp-initialization-on-empty-clock.patch	2021-08-03 12:35:08.230819049 +0100
@@ -1 +1 @@
-From dab07e489cd5be47a017e0b8558b3fe3ee03b979 Mon Sep 17 00:00:00 2001
+From f46e2c750ac23a6c6f53b64c99c76a6c02111971 Mon Sep 17 00:00:00 2001
@@ -5,0 +6,2 @@
+[ upstream commit dab07e489cd5be47a017e0b8558b3fe3ee03b979 ]
+
@@ -21 +22,0 @@
-Cc: stable at dpdk.org
@@ -29 +30 @@
-index d90399afb5..4f6da9f2d1 100644
+index 72b0690913..cf11048160 100644
@@ -32 +33 @@
-@@ -530,8 +530,8 @@ mlx5_atomic_read_cqe(rte_int128_t *from, rte_int128_t *ts)
+@@ -676,8 +676,8 @@ mlx5_atomic_read_cqe(rte_int128_t *from, rte_int128_t *ts)
@@ -43 +44 @@
-@@ -592,13 +592,22 @@ mlx5_txpp_update_timestamp(struct mlx5_dev_ctx_shared *sh)
+@@ -738,15 +738,24 @@ mlx5_txpp_update_timestamp(struct mlx5_dev_ctx_shared *sh)
@@ -48,0 +50,2 @@
+ 	static_assert(sizeof(struct mlx5_cqe_ts) == sizeof(rte_int128_t),
+ 		      "Wrong timestamp CQE part size");