Re: [PATCH net-next 3/3] net/mlx5: add debugfs stats for doorbell dma pools

[Leon Romanovsky <leon@kernel.org>]

On Thu, Jul 23, 2026 at 10:22:22AM +0300, Tariq Toukan wrote:
> From: Nimrod Oren <noren@nvidia.com>
> 
> Add a debugfs file exposing per-node DMA pool usage for doorbell
> allocations.
> 
>   # cat /sys/kernel/debug/mlx5/<dev>/db_dma_pools
>   node  block_size  used_blocks  allocated_blocks
>      0          64            0                 0
>      1          64            0                 0
> 
> Signed-off-by: Nimrod Oren <noren@nvidia.com>
> Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
> ---
>  .../net/ethernet/mellanox/mlx5/core/alloc.c   | 30 +++++++++++++++++++
>  include/linux/mlx5/driver.h                   |  1 +
>  2 files changed, 31 insertions(+)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/alloc.c b/drivers/net/ethernet/mellanox/mlx5/core/alloc.c
> index 3975c726d35c..60ff413999f7 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/alloc.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/alloc.c
> @@ -437,11 +437,37 @@ void mlx5_frag_buf_free(struct mlx5_core_dev *dev, struct mlx5_frag_buf *buf)
>  }
>  EXPORT_SYMBOL_GPL(mlx5_frag_buf_free);
>  
> +static int mlx5_db_dma_pools_debugfs_show(struct seq_file *file, void *priv)
> +{
> +	struct mlx5_core_dev *dev = file->private;
> +	int node;
> +
> +	mlx5_dma_pools_debugfs_print_header(file);
> +
> +	if (!dev->priv.db_node_pools)
> +		return 0;

According to patch #1, this check is useless. You are failing mlx5 probe
function if DMA pools initialization failed.

Thanks

> +
> +	for_each_node_state(node, N_POSSIBLE) {
> +		struct mlx5_dma_pool *pool = dev->priv.db_node_pools[node];
> +
> +		if (!pool)
> +			continue;
> +
> +		mlx5_dma_pool_debugfs_stats_print(file, pool);
> +	}
> +
> +	return 0;
> +}
> +DEFINE_SHOW_ATTRIBUTE(mlx5_db_dma_pools_debugfs);
> +
>  void mlx5_db_pools_cleanup(struct mlx5_core_dev *dev)
>  {
>  	struct mlx5_priv *priv = &dev->priv;
>  	int node;
>  
> +	debugfs_remove(priv->dbg.db_dma_pools_debugfs);
> +	priv->dbg.db_dma_pools_debugfs = NULL;
> +
>  	for_each_node_state(node, N_POSSIBLE)
>  		if (priv->db_node_pools[node])
>  			mlx5_dma_pool_destroy(priv->db_node_pools[node]);
> @@ -471,6 +497,10 @@ int mlx5_db_pools_init(struct mlx5_core_dev *dev)
>  		priv->db_node_pools[node] = pool;
>  	}
>  
> +	priv->dbg.db_dma_pools_debugfs =
> +		debugfs_create_file("db_dma_pools", 0444, priv->dbg.dbg_root,
> +				    dev, &mlx5_db_dma_pools_debugfs_fops);
> +
>  	return 0;
>  }
>  
> diff --git a/include/linux/mlx5/driver.h b/include/linux/mlx5/driver.h
> index 2c56bb1d676d..83d0a83bbfbc 100644
> --- a/include/linux/mlx5/driver.h
> +++ b/include/linux/mlx5/driver.h
> @@ -548,6 +548,7 @@ struct mlx5_debugfs_entries {
>  	struct dentry *cq_debugfs;
>  	struct dentry *cmdif_debugfs;
>  	struct dentry *frag_buf_dma_pools_debugfs;
> +	struct dentry *db_dma_pools_debugfs;
>  	struct dentry *pages_debugfs;
>  	struct dentry *lag_debugfs;
>  };
> -- 
> 2.44.0
>