[PATCH] net/mlx5: fix condition to avoid Tx failure

[PATCH] net/mlx5: fix condition to avoid Tx failure

[Viacheslav Ovsiienko]

From: Raja Zidane <rzidane@nvidia.com>

If hardware descriptor (WQE) length exceeds one the HW can handle,
the Tx queue failure occurs. PMD does the length check but there was
a bug - the length limit was expressed in 16B units (WQEBB segments),
while the calculated WQE length and limit were in 64B units (WQEBBs).
Fix the condition to avoid subsequent Tx queue failure.

Fixes: 18a1c20 ("net/mlx5: implement Tx burst template")
Cc: stable@dpdk.org

Signed-off-by: Raja Zidane <rzidane@nvidia.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
---
 drivers/net/mlx5/mlx5_tx.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/mlx5/mlx5_tx.h b/drivers/net/mlx5/mlx5_tx.h
index 59ebe95032..e0fc1872fe 100644
--- a/drivers/net/mlx5/mlx5_tx.h
+++ b/drivers/net/mlx5/mlx5_tx.h
@@ -1783,7 +1783,7 @@ mlx5_tx_packet_multi_tso(struct mlx5_txq_data *__rte_restrict txq,
 	if (unlikely(loc->wqe_free < ((ds + 3) / 4)))
 		return MLX5_TXCMP_CODE_EXIT;
 	/* Check for maximal WQE size. */
-	if (unlikely((MLX5_WQE_SIZE_MAX / MLX5_WSEG_SIZE) < ((ds + 3) / 4)))
+	if (unlikely((MLX5_WQE_SIZE_MAX / MLX5_WSEG_SIZE) < ds))
 		return MLX5_TXCMP_CODE_ERROR;
 #ifdef MLX5_PMD_SOFT_COUNTERS
 	/* Update sent data bytes/packets counters. */
@@ -1858,7 +1858,7 @@ mlx5_tx_packet_multi_send(struct mlx5_txq_data *__rte_restrict txq,
 	if (unlikely(loc->wqe_free < ((ds + 3) / 4)))
 		return MLX5_TXCMP_CODE_EXIT;
 	/* Check for maximal WQE size. */
-	if (unlikely((MLX5_WQE_SIZE_MAX / MLX5_WSEG_SIZE) < ((ds + 3) / 4)))
+	if (unlikely((MLX5_WQE_SIZE_MAX / MLX5_WSEG_SIZE) < ds))
 		return MLX5_TXCMP_CODE_ERROR;
 	/*
 	 * Some Tx offloads may cause an error if packet is not long enough,
-- 
2.18.1

RE: [PATCH] net/mlx5: fix condition to avoid Tx failure

[Raslan Darawsheh]

Hi,

> -----Original Message-----
> From: Slava Ovsiienko <viacheslavo@nvidia.com>
> Sent: Wednesday, August 17, 2022 5:15 PM
> To: dev@dpdk.org
> Cc: Matan Azrad <matan@nvidia.com>; Raslan Darawsheh
> <rasland@nvidia.com>; Dmitry Kozlyuk <dkozlyuk@nvidia.com>; Raja Zidane
> <rzidane@nvidia.com>; stable@dpdk.org
> Subject: [PATCH] net/mlx5: fix condition to avoid Tx failure
> 
> From: Raja Zidane <rzidane@nvidia.com>
> 
> If hardware descriptor (WQE) length exceeds one the HW can handle,
> the Tx queue failure occurs. PMD does the length check but there was
> a bug - the length limit was expressed in 16B units (WQEBB segments),
> while the calculated WQE length and limit were in 64B units (WQEBBs).
> Fix the condition to avoid subsequent Tx queue failure.
> 
> Fixes: 18a1c20 ("net/mlx5: implement Tx burst template")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Raja Zidane <rzidane@nvidia.com>
> Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>

Patch applied to next-net-mlx,

Kindest regards,
Raslan Darawsheh