[PATCH] net/mlx5: fix MPRQ pool registration

[Xueming(Steven) Li]

It's 20.11 LTS patch, applied and thanks!

> -----Original Message-----
> From: Dmitry Kozlyuk <dkozlyuk at nvidia.com>
> Sent: Monday, August 15, 2022 3:27 PM
> To: stable at dpdk.org
> Cc: Xueming(Steven) Li <xuemingl at nvidia.com>; Luca Boccassi <bluca at debian.org>; Slava Ovsiienko <viacheslavo at nvidia.com>
> Subject: [PATCH] net/mlx5: fix MPRQ pool registration
> 
> mlx5_mr_update_mp() was checking pktmbuf pool private flags.
> However, this function may be passed an MPRQ pool, which is not a pktmbuf pool and has no private data.
> Random data is accessed instead of pktmbuf flags, causing a crash.
> Move the flags check to the RxQ start and only for pools that are known to be of pktmbuf type.
> 
> Fixes: 23b584d6cc85 ("net/mlx5: fix external buffer pool registration for Rx queue")
> 
> Signed-off-by: Dmitry Kozlyuk <dkozlyuk at nvidia.com>
> Acked-by: Viacheslav Ovsiienko <viacheslavo at nvidia.com>
> ---
>  drivers/net/mlx5/mlx5_mr.c      | 11 -----------
>  drivers/net/mlx5/mlx5_trigger.c | 21 +++++++++++++++++++--
>  2 files changed, 19 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/net/mlx5/mlx5_mr.c b/drivers/net/mlx5/mlx5_mr.c index 1dd14ddfe5..2a7fac8ad3 100644
> --- a/drivers/net/mlx5/mlx5_mr.c
> +++ b/drivers/net/mlx5/mlx5_mr.c
> @@ -444,18 +444,7 @@ mlx5_mr_update_mp(struct rte_eth_dev *dev, struct mlx5_mr_ctrl *mr_ctrl,
>  		.mr_ctrl = mr_ctrl,
>  		.ret = 0,
>  	};
> -	uint32_t flags = rte_pktmbuf_priv_flags(mp);
> 
> -	if (flags & RTE_PKTMBUF_POOL_F_PINNED_EXT_BUF) {
> -		/*
> -		 * The pinned external buffer should be registered for DMA
> -		 * operations by application. The mem_list of the pool contains
> -		 * the list of chunks with mbuf structures w/o built-in data
> -		 * buffers and DMA actually does not happen there, no need
> -		 * to create MR for these chunks.
> -		 */
> -		return 0;
> -	}
>  	DRV_LOG(DEBUG, "Port %u Rx queue registering mp %s "
>  		       "having %u chunks.", dev->data->port_id,
>  		       mp->name, mp->nb_mem_chunks);
> diff --git a/drivers/net/mlx5/mlx5_trigger.c b/drivers/net/mlx5/mlx5_trigger.c index c8dc0398ea..9b82ee40fd 100644
> --- a/drivers/net/mlx5/mlx5_trigger.c
> +++ b/drivers/net/mlx5/mlx5_trigger.c
> @@ -156,12 +156,29 @@ mlx5_rxq_start(struct rte_eth_dev *dev)
>  				mlx5_mr_update_mp(dev, &rxq_ctrl->rxq.mr_ctrl,
>  						  rxq_ctrl->rxq.mprq_mp);
>  			} else {
> +				struct rte_mempool *mp;
> +				uint32_t flags;
>  				uint32_t s;
> 
> -				for (s = 0; s < rxq_ctrl->rxq.rxseg_n; s++)
> +				/*
> +				 * The pinned external buffer should be
> +				 * registered for DMA operations by application.
> +				 * The mem_list of the pool contains
> +				 * the list of chunks with mbuf structures
> +				 * w/o built-in data buffers
> +				 * and DMA actually does not happen there,
> +				 * no need to create MR for these chunks.
> +				 */
> +				for (s = 0; s < rxq_ctrl->rxq.rxseg_n; s++) {
> +					mp = rxq_ctrl->rxq.rxseg[s].mp;
> +					flags = rte_pktmbuf_priv_flags(mp);
> +					if (flags &
> +					    RTE_PKTMBUF_POOL_F_PINNED_EXT_BUF)
> +						continue;
>  					mlx5_mr_update_mp
>  						(dev, &rxq_ctrl->rxq.mr_ctrl,
> -						rxq_ctrl->rxq.rxseg[s].mp);
> +						 mp);
> +				}
>  			}
>  			ret = rxq_alloc_elts(rxq_ctrl);
>  			if (ret)
> --
> 2.25.1