Re: [PATCH v4 net-next 7/7] net: mvneta: add XDP_TX support

[Lorenzo Bianconi <lorenzo@kernel.org>]

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> On Wed, 16 Oct 2019 23:03:12 +0200, Lorenzo Bianconi wrote:
> > Implement XDP_TX verdict and ndo_xdp_xmit net_device_ops function
> > pointer
> > 
> > Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> 
> > +static int
> > +mvneta_xdp_submit_frame(struct mvneta_port *pp, struct mvneta_tx_queue *txq,
> > +			struct xdp_frame *xdpf, bool dma_map)
> > +{
> > +	struct mvneta_tx_desc *tx_desc;
> > +	struct mvneta_tx_buf *buf;
> > +	dma_addr_t dma_addr;
> > +
> > +	if (txq->count >= txq->tx_stop_threshold)
> > +		return MVNETA_XDP_DROPPED;
> > +
> > +	tx_desc = mvneta_txq_next_desc_get(txq);
> > +
> > +	buf = &txq->buf[txq->txq_put_index];
> > +	if (dma_map) {
> > +		/* ndo_xdp_xmit */
> > +		dma_addr = dma_map_single(pp->dev->dev.parent, xdpf->data,
> > +					  xdpf->len, DMA_TO_DEVICE);
> > +		if (dma_mapping_error(pp->dev->dev.parent, dma_addr)) {
> > +			mvneta_txq_desc_put(txq);
> > +			return MVNETA_XDP_DROPPED;
> > +		}
> > +		buf->type = MVNETA_TYPE_XDP_NDO;
> > +	} else {
> > +		struct page *page = virt_to_page(xdpf->data);
> > +
> > +		dma_addr = page_pool_get_dma_addr(page) +
> > +			   xdpf->headroom + sizeof(*xdpf);
> 
> nit:
> 
>  sizeof(*xdpf) + xdpf->headroom
> 
> order would be slightly preferable since it matches field ordering in
> memory.

ack, agree. Will do in v5.

Regards,
Lorenzo

> 
> > +		dma_sync_single_for_device(pp->dev->dev.parent, dma_addr,
> > +					   xdpf->len, DMA_BIDIRECTIONAL);
> > +		buf->type = MVNETA_TYPE_XDP_TX;
> > +	}
> > +	buf->xdpf = xdpf;
> > +
> > +	tx_desc->command = MVNETA_TXD_FLZ_DESC;
> > +	tx_desc->buf_phys_addr = dma_addr;
> > +	tx_desc->data_size = xdpf->len;
> > +
> > +	mvneta_update_stats(pp, 1, xdpf->len, true);
> > +	mvneta_txq_inc_put(txq);
> > +	txq->pending++;
> > +	txq->count++;
> > +
> > +	return MVNETA_XDP_TX;
> > +}

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