Re: [PATCH net-next v2 1/3] xsk: Remove non-zero 'dma_page' check in xp_assign_dev

[Paolo Abeni <pabeni@redhat.com>]

On Wed, 2024-02-28 at 19:05 +0800, Yunjian Wang wrote:
> Now dma mappings are used by the physical NICs. However the vNIC
> maybe do not need them. So remove non-zero 'dma_page' check in
> xp_assign_dev.
> 
> Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
> ---
>  net/xdp/xsk_buff_pool.c | 7 -------
>  1 file changed, 7 deletions(-)
> 
> diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c
> index ce60ecd48a4d..a5af75b1f43c 100644
> --- a/net/xdp/xsk_buff_pool.c
> +++ b/net/xdp/xsk_buff_pool.c
> @@ -219,16 +219,9 @@ int xp_assign_dev(struct xsk_buff_pool *pool,
>  	if (err)
>  		goto err_unreg_pool;
>  
> -	if (!pool->dma_pages) {
> -		WARN(1, "Driver did not DMA map zero-copy buffers");
> -		err = -EINVAL;
> -		goto err_unreg_xsk;
> -	}

This would unconditionally remove an otherwise valid check for most
NIC. What about let the driver declare it wont need DMA map with a
(pool?) flag.

Cheers,

Paolo