patch 'net/mlx5: fix error packets drop in regular Rx' has been queued to stable release 23.11.1

[Xueming Li]

Hi,

FYI, your patch has been queued to stable release 23.11.1

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 04/15/24. 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://git.dpdk.org/dpdk-stable/log/?h=23.11-staging

This queued commit can be viewed at:
https://git.dpdk.org/dpdk-stable/commit/?h=23.11-staging&id=bfa6cbba4c6cffa1e3a27c17a6f8e89644f340a1

Thanks.

Xueming Li <xuemingl at nvidia.com>

---
>From bfa6cbba4c6cffa1e3a27c17a6f8e89644f340a1 Mon Sep 17 00:00:00 2001
From: Viacheslav Ovsiienko <viacheslavo at nvidia.com>
Date: Tue, 20 Feb 2024 13:45:20 +0200
Subject: [PATCH] net/mlx5: fix error packets drop in regular Rx
Cc: Xueming Li <xuemingl at nvidia.com>

[ upstream commit ef296e8f6140ea469b50c7bfe73501b1c9ef86e1 ]

When packet gets received with error it is reported in CQE
structure and PMD analyzes the error syndrome and provides
two options - either reset the entire queue for the critical
errors, or just ignore the packet.

The non-vectorized rx_burst did not ignore the non-critical
error packets, and in case of packet length exceeding the
mbuf data buffer length it took the next element in the queue
WQE ring, resulting in CQE/WQE consume indices synchronization
lost.

Fixes: aa67ed308458 ("net/mlx5: ignore non-critical syndromes for Rx queue")

Signed-off-by: Viacheslav Ovsiienko <viacheslavo at nvidia.com>
Acked-by: Dariusz Sosnowski <dsosnowski at nvidia.com>
---
 drivers/net/mlx5/mlx5_rx.c | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/drivers/net/mlx5/mlx5_rx.c b/drivers/net/mlx5/mlx5_rx.c
index 5bf1a679b2..cc087348a4 100644
--- a/drivers/net/mlx5/mlx5_rx.c
+++ b/drivers/net/mlx5/mlx5_rx.c
@@ -613,7 +613,8 @@ mlx5_rx_err_handle(struct mlx5_rxq_data *rxq, uint8_t vec,
  * @param mprq
  *   Indication if it is called from MPRQ.
  * @return
- *   0 in case of empty CQE, MLX5_REGULAR_ERROR_CQE_RET in case of error CQE,
+ *   0 in case of empty CQE,
+ *   MLX5_REGULAR_ERROR_CQE_RET in case of error CQE,
  *   MLX5_CRITICAL_ERROR_CQE_RET in case of error CQE lead to Rx queue reset,
  *   otherwise the packet size in regular RxQ,
  *   and striding byte count format in mprq case.
@@ -697,6 +698,11 @@ mlx5_rx_poll_len(struct mlx5_rxq_data *rxq, volatile struct mlx5_cqe *cqe,
 					if (ret == MLX5_RECOVERY_ERROR_RET ||
 						ret == MLX5_RECOVERY_COMPLETED_RET)
 						return MLX5_CRITICAL_ERROR_CQE_RET;
+					if (!mprq && ret == MLX5_RECOVERY_IGNORE_RET) {
+						*skip_cnt = 1;
+						++rxq->cq_ci;
+						return MLX5_ERROR_CQE_MASK;
+					}
 				} else {
 					return 0;
 				}
@@ -971,19 +977,18 @@ mlx5_rx_burst(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n)
 			cqe = &(*rxq->cqes)[rxq->cq_ci & cqe_mask];
 			len = mlx5_rx_poll_len(rxq, cqe, cqe_n, cqe_mask, &mcqe, &skip_cnt, false);
 			if (unlikely(len & MLX5_ERROR_CQE_MASK)) {
+				/* We drop packets with non-critical errors */
+				rte_mbuf_raw_free(rep);
 				if (len == MLX5_CRITICAL_ERROR_CQE_RET) {
-					rte_mbuf_raw_free(rep);
 					rq_ci = rxq->rq_ci << sges_n;
 					break;
 				}
+				/* Skip specified amount of error CQEs packets */
 				rq_ci >>= sges_n;
 				rq_ci += skip_cnt;
 				rq_ci <<= sges_n;
-				idx = rq_ci & wqe_mask;
-				wqe = &((volatile struct mlx5_wqe_data_seg *)rxq->wqes)[idx];
-				seg = (*rxq->elts)[idx];
-				cqe = &(*rxq->cqes)[rxq->cq_ci & cqe_mask];
-				len = len & ~MLX5_ERROR_CQE_MASK;
+				MLX5_ASSERT(!pkt);
+				continue;
 			}
 			if (len == 0) {
 				rte_mbuf_raw_free(rep);
-- 
2.34.1

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2024-04-13 20:43:06.552569301 +0800
+++ 0049-net-mlx5-fix-error-packets-drop-in-regular-Rx.patch	2024-04-13 20:43:04.967753971 +0800
@@ -1 +1 @@
-From ef296e8f6140ea469b50c7bfe73501b1c9ef86e1 Mon Sep 17 00:00:00 2001
+From bfa6cbba4c6cffa1e3a27c17a6f8e89644f340a1 Mon Sep 17 00:00:00 2001
@@ -4,0 +5,3 @@
+Cc: Xueming Li <xuemingl at nvidia.com>
+
+[ upstream commit ef296e8f6140ea469b50c7bfe73501b1c9ef86e1 ]
@@ -18 +20,0 @@
-Cc: stable at dpdk.org