Re: [PATCH net-next 10/20] xsk: Move pool registration into single function

[Maciej Fijalkowski <maciej.fijalkowski@intel.com>]

On Fri, Sep 19, 2025 at 11:31:43PM +0200, Daniel Borkmann wrote:
> Small refactor to move the pool registration into xsk_reg_pool_at_qid,
> such that the netdev and queue_id can be registered there. No change
> in functionality.
> 
> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
> Co-developed-by: David Wei <dw@davidwei.uk>
> Signed-off-by: David Wei <dw@davidwei.uk>
> ---
>  net/xdp/xsk.c           |  5 +++++
>  net/xdp/xsk_buff_pool.c | 16 +++-------------
>  2 files changed, 8 insertions(+), 13 deletions(-)
> 
> diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
> index 72e34bd2d925..82ad89f6ba35 100644
> --- a/net/xdp/xsk.c
> +++ b/net/xdp/xsk.c
> @@ -141,6 +141,11 @@ int xsk_reg_pool_at_qid(struct net_device *dev, struct xsk_buff_pool *pool,
>  			      dev->real_num_rx_queues,
>  			      dev->real_num_tx_queues))
>  		return -EINVAL;
> +	if (xsk_get_pool_from_qid(dev, queue_id))
> +		return -EBUSY;
> +
> +	pool->netdev = dev;
> +	pool->queue_id = queue_id;
>  
>  	if (queue_id < dev->real_num_rx_queues)
>  		dev->_rx[queue_id].pool = pool;
> diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c
> index 26165baf99f4..375696f895d4 100644
> --- a/net/xdp/xsk_buff_pool.c
> +++ b/net/xdp/xsk_buff_pool.c
> @@ -169,32 +169,24 @@ int xp_assign_dev(struct xsk_buff_pool *pool,
>  
>  	force_zc = flags & XDP_ZEROCOPY;
>  	force_copy = flags & XDP_COPY;
> -
>  	if (force_zc && force_copy)
>  		return -EINVAL;
>  
> -	if (xsk_get_pool_from_qid(netdev, queue_id))
> -		return -EBUSY;
> -
> -	pool->netdev = netdev;
> -	pool->queue_id = queue_id;
>  	err = xsk_reg_pool_at_qid(netdev, pool, queue_id);
>  	if (err)
>  		return err;
>  
>  	if (flags & XDP_USE_SG)
>  		pool->umem->flags |= XDP_UMEM_SG_FLAG;
> -

IMHO all of the stuff below looks like unnecessary code churn.

>  	if (flags & XDP_USE_NEED_WAKEUP)
>  		pool->uses_need_wakeup = true;
> -	/* Tx needs to be explicitly woken up the first time.  Also
> -	 * for supporting drivers that do not implement this
> -	 * feature. They will always have to call sendto() or poll().
> +	/* Tx needs to be explicitly woken up the first time. Also
> +	 * for supporting drivers that do not implement this feature.
> +	 * They will always have to call sendto() or poll().
>  	 */
>  	pool->cached_need_wakeup = XDP_WAKEUP_TX;
>  
>  	dev_hold(netdev);
> -
>  	if (force_copy)
>  		/* For copy-mode, we are done. */
>  		return 0;
> @@ -203,12 +195,10 @@ int xp_assign_dev(struct xsk_buff_pool *pool,
>  		err = -EOPNOTSUPP;
>  		goto err_unreg_pool;
>  	}
> -
>  	if (netdev->xdp_zc_max_segs == 1 && (flags & XDP_USE_SG)) {
>  		err = -EOPNOTSUPP;
>  		goto err_unreg_pool;
>  	}
> -
>  	if (dev_get_min_mp_channel_count(netdev)) {
>  		err = -EBUSY;
>  		goto err_unreg_pool;
> -- 
> 2.43.0
>