Re: [PATCH v9 1/2] IB/mlx5: Fix transport-domain rollback and initialize lb mutex earlier

[Leon Romanovsky]

On Fri, Apr 10, 2026 at 01:52:17AM +0100, Prathamesh Deshpande wrote:
> mlx5_ib_alloc_transport_domain() allocates a transport domain and then
> may fail in mlx5_ib_enable_lb(). In that case, the allocated TD is leaked.
> 
> Fix this by deallocating the TD when mlx5_ib_enable_lb() returns an
> error. Also return 0 explicitly in the no-loopback-capability success
> branch, and move dev->lb.mutex initialization to mlx5_ib_stage_init_init().
> 
> Fixes: 146d2f1af324 ("IB/mlx5: Allocate a Transport Domain for each ucontext")
> Signed-off-by: Prathamesh Deshpande <prathameshdeshpande7@xxxxxxxxx>
> ---
>  drivers/infiniband/hw/mlx5/main.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
> index e02bfb1479f5..6be198c0651c 100644
> --- a/drivers/infiniband/hw/mlx5/main.c
> +++ b/drivers/infiniband/hw/mlx5/main.c
> @@ -2068,9 +2068,13 @@ static int mlx5_ib_alloc_transport_domain(struct mlx5_ib_dev *dev, u32 *tdn,
>  	if ((MLX5_CAP_GEN(dev->mdev, port_type) != MLX5_CAP_PORT_TYPE_ETH) ||
>  	    (!MLX5_CAP_GEN(dev->mdev, disable_local_lb_uc) &&
>  	     !MLX5_CAP_GEN(dev->mdev, disable_local_lb_mc)))
> -		return err;
> +		return 0;
> +
> +	err = mlx5_ib_enable_lb(dev, true, false);
> +	if (err)
> +		mlx5_cmd_dealloc_transport_domain(dev->mdev, *tdn, uid);
>  
> -	return mlx5_ib_enable_lb(dev, true, false);
> +	return err;
>  }
>  
>  static void mlx5_ib_dealloc_transport_domain(struct mlx5_ib_dev *dev, u32 tdn,
> @@ -4513,6 +4517,7 @@ static int mlx5_ib_stage_init_init(struct mlx5_ib_dev *dev)
>  
>  	mutex_init(&dev->cap_mask_mutex);
>  	mutex_init(&dev->data_direct_lock);
> +	mutex_init(&dev->lb.mutex);

There is also a need to call mutex_destroy() to ensure proper resource cleanup.

Thanks

>  	INIT_LIST_HEAD(&dev->qp_list);
>  	spin_lock_init(&dev->reset_flow_resource_lock);
>  	xa_init(&dev->odp_mkeys);
> @@ -4786,11 +4791,6 @@ static int mlx5_ib_stage_caps_init(struct mlx5_ib_dev *dev)
>  	if (err)
>  		return err;
>  
> -	if ((MLX5_CAP_GEN(dev->mdev, port_type) == MLX5_CAP_PORT_TYPE_ETH) &&
> -	    (MLX5_CAP_GEN(dev->mdev, disable_local_lb_uc) ||
> -	     MLX5_CAP_GEN(dev->mdev, disable_local_lb_mc)))
> -		mutex_init(&dev->lb.mutex);
> -
>  	if (MLX5_CAP_GEN_64(dev->mdev, general_obj_types) &
>  			MLX5_GENERAL_OBJ_TYPES_CAP_VIRTIO_NET_Q) {
>  		err = mlx5_ib_init_var_region(dev);
> -- 
> 2.43.0
>