Re: [PATCH iwl-next 03/10] ixgbevf: use libeth in Rx processing

[Larysa Zaremba]

On Tue, Feb 24, 2026 at 05:45:50PM +0000, Simon Horman wrote:
> On Mon, Feb 23, 2026 at 10:52:10AM +0100, Larysa Zaremba wrote:
> > Use page_pool buffers by the means of libeth in the Rx queues, this
> > significantly reduces code complexity of the driver itself.
> > 
> > Suggested-by: Alexander Lobakin <aleksander.lobakin@xxxxxxxxx>
> > Reviewed-by: Alexander Lobakin <aleksander.lobakin@xxxxxxxxx>
> > Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@xxxxxxxxx>
> > Signed-off-by: Larysa Zaremba <larysa.zaremba@xxxxxxxxx>
> 
> ...
> 
> > @@ -3257,12 +3133,26 @@ static int ixgbevf_setup_all_tx_resources(struct ixgbevf_adapter *adapter)
> >  int ixgbevf_setup_rx_resources(struct ixgbevf_adapter *adapter,
> >  			       struct ixgbevf_ring *rx_ring)
> >  {
> > -	int size;
> > +	struct libeth_fq fq = {
> > +		.count		= rx_ring->count,
> > +		.nid		= NUMA_NO_NODE,
> > +		.type		= LIBETH_FQE_MTU,
> > +		.xdp		= !!rx_ring->xdp_prog,
> > +		.idx		= rx_ring->queue_index,
> > +		.buf_len	= IXGBEVF_RX_PAGE_LEN(rx_ring->xdp_prog ?
> > +						      LIBETH_XDP_HEADROOM :
> > +						      LIBETH_SKB_HEADROOM),
> > +	};
> > +	int ret;
> >  
> > -	size = sizeof(struct ixgbevf_rx_buffer) * rx_ring->count;
> > -	rx_ring->rx_buffer_info = vmalloc(size);
> > -	if (!rx_ring->rx_buffer_info)
> > -		goto err;
> > +	ret = libeth_rx_fq_create(&fq, &rx_ring->q_vector->napi);
> > +	if (ret)
> > +		return ret;
> > +
> > +	rx_ring->pp = fq.pp;
> > +	rx_ring->rx_fqes = fq.fqes;
> > +	rx_ring->truesize = fq.truesize;
> > +	rx_ring->rx_buf_len = fq.buf_len;
> >  
> >  	u64_stats_init(&rx_ring->syncp);
> >  
> > @@ -3270,25 +3160,29 @@ int ixgbevf_setup_rx_resources(struct ixgbevf_adapter *adapter,
> >  	rx_ring->size = rx_ring->count * sizeof(union ixgbe_adv_rx_desc);
> >  	rx_ring->size = ALIGN(rx_ring->size, 4096);
> >  
> > -	rx_ring->desc = dma_alloc_coherent(rx_ring->dev, rx_ring->size,
> > +	rx_ring->desc = dma_alloc_coherent(fq.pp->p.dev, rx_ring->size,
> >  					   &rx_ring->dma, GFP_KERNEL);
> >  
> >  	if (!rx_ring->desc)
> 
> Hi Larysa,
> 
> Prior to this patch, if this error condition was met,
> then function would return -ENOMEM. But now it will return 0.
> This does not seem intentional.
> 
> Flagged by Smatch.

No, it is not intentional, though the problem is fixed in a later patch. Will 
correct this one in v2.

> 
> >  		goto err;
> >  
> >  	/* XDP RX-queue info */
> > -	if (xdp_rxq_info_reg(&rx_ring->xdp_rxq, adapter->netdev,
> > -			     rx_ring->queue_index, 0) < 0)
> > +	ret = __xdp_rxq_info_reg(&rx_ring->xdp_rxq, adapter->netdev,
> > +				 rx_ring->queue_index, 0, rx_ring->truesize);
> > +	if (ret)
> >  		goto err;
> >  
> > +	xdp_rxq_info_attach_page_pool(&rx_ring->xdp_rxq, fq.pp);
> > +
> >  	rx_ring->xdp_prog = adapter->xdp_prog;
> >  
> >  	return 0;
> >  err:
> > -	vfree(rx_ring->rx_buffer_info);
> > -	rx_ring->rx_buffer_info = NULL;
> > +	libeth_rx_fq_destroy(&fq);
> > +	rx_ring->rx_fqes = NULL;
> > +	rx_ring->pp = NULL;
> >  	dev_err(rx_ring->dev, "Unable to allocate memory for the Rx descriptor ring\n");
> > -	return -ENOMEM;
> > +	return ret;
> >  }
> >  
> >  /**
> 
> ...