linux-kernel - Re: [PATCH v2 net-next 05/14] net: fec: improve fec_enet_rx

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Message-ID: <aWpFLnaKDPU5ThFn@lizhi-Precision-Tower-5810>
Date: Fri, 16 Jan 2026 09:03:26 -0500
From: Frank Li <Frank.li@....com>
To: Wei Fang <wei.fang@....com>
Cc: shenwei.wang@....com, xiaoning.wang@....com, andrew+netdev@...n.ch,
	davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
	pabeni@...hat.com, ast@...nel.org, daniel@...earbox.net,
	hawk@...nel.org, john.fastabend@...il.com, sdf@...ichev.me,
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
	imx@...ts.linux.dev, bpf@...r.kernel.org
Subject: Re: [PATCH v2 net-next 05/14] net: fec: improve fec_enet_rx_queue()

On Fri, Jan 16, 2026 at 03:40:18PM +0800, Wei Fang wrote:
> This patch has made the following adjustments to fec_enet_rx_queue().
>
> 1. The function parameters are modified to maintain the same style as
> subsequently added XDP-related interfaces.
>
> 2. Some variables are initialized at the time of declaration, and the
> order of local variables is updated to follow the reverse xmas tree
> style.
>
> 3. Replace variable cbd_bufaddr with dma.
>
> Signed-off-by: Wei Fang <wei.fang@....com>
> ---
Reviewed-by: Frank Li <Frank.Li@....com>

>  drivers/net/ethernet/freescale/fec_main.c | 35 ++++++++++-------------
>  1 file changed, 15 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
> index 7e8ac9d2a5ff..0529dc91c981 100644
> --- a/drivers/net/ethernet/freescale/fec_main.c
> +++ b/drivers/net/ethernet/freescale/fec_main.c
> @@ -1839,26 +1839,25 @@ static struct sk_buff *fec_build_skb(struct fec_enet_private *fep,
>   * not been given to the system, we just set the empty indicator,
>   * effectively tossing the packet.
>   */
> -static int
> -fec_enet_rx_queue(struct net_device *ndev, u16 queue_id, int budget)
> +static int fec_enet_rx_queue(struct fec_enet_private *fep,
> +			     u16 queue, int budget)
>  {
> -	struct fec_enet_private *fep = netdev_priv(ndev);
> -	struct fec_enet_priv_rx_q *rxq;
> -	struct bufdesc *bdp;
> -	unsigned short status;
> -	struct  sk_buff *skb;
> -	ushort	pkt_len;
> -	int	pkt_received = 0;
> -	int	index = 0;
> -	bool	need_swap = fep->quirks & FEC_QUIRK_SWAP_FRAME;
>  	u32 data_start = FEC_ENET_XDP_HEADROOM + fep->rx_shift;
> +	struct fec_enet_priv_rx_q *rxq = fep->rx_queue[queue];
>  	struct bpf_prog *xdp_prog = READ_ONCE(fep->xdp_prog);
> +	bool need_swap = fep->quirks & FEC_QUIRK_SWAP_FRAME;
>  	u32 ret, xdp_result = FEC_ENET_XDP_PASS;
> +	struct net_device *ndev = fep->netdev;
> +	struct bufdesc *bdp = rxq->bd.cur;
>  	u32 sub_len = 4 + fep->rx_shift;
>  	int cpu = smp_processor_id();
> +	int pkt_received = 0;
> +	u16 status, pkt_len;
> +	struct sk_buff *skb;
>  	struct xdp_buff xdp;
>  	struct page *page;
> -	__fec32 cbd_bufaddr;
> +	dma_addr_t dma;
> +	int index;
>
>  #if defined(CONFIG_COLDFIRE) && !defined(CONFIG_COLDFIRE_COHERENT_DMA)
>  	/*
> @@ -1867,12 +1866,10 @@ fec_enet_rx_queue(struct net_device *ndev, u16 queue_id, int budget)
>  	 */
>  	flush_cache_all();
>  #endif
> -	rxq = fep->rx_queue[queue_id];
>
>  	/* First, grab all of the stats for the incoming packet.
>  	 * These get messed up if we get called due to a busy condition.
>  	 */
> -	bdp = rxq->bd.cur;
>  	xdp_init_buff(&xdp, PAGE_SIZE << fep->pagepool_order, &rxq->xdp_rxq);
>
>  	while (!((status = fec16_to_cpu(bdp->cbd_sc)) & BD_ENET_RX_EMPTY)) {
> @@ -1881,7 +1878,7 @@ fec_enet_rx_queue(struct net_device *ndev, u16 queue_id, int budget)
>  			break;
>  		pkt_received++;
>
> -		writel(FEC_ENET_RXF_GET(queue_id), fep->hwp + FEC_IEVENT);
> +		writel(FEC_ENET_RXF_GET(queue), fep->hwp + FEC_IEVENT);
>
>  		/* Check for errors. */
>  		status ^= BD_ENET_RX_LAST;
> @@ -1895,15 +1892,13 @@ fec_enet_rx_queue(struct net_device *ndev, u16 queue_id, int budget)
>
>  		index = fec_enet_get_bd_index(bdp, &rxq->bd);
>  		page = rxq->rx_buf[index];
> -		cbd_bufaddr = bdp->cbd_bufaddr;
> +		dma = fec32_to_cpu(bdp->cbd_bufaddr);
>  		if (fec_enet_update_cbd(rxq, bdp, index)) {
>  			ndev->stats.rx_dropped++;
>  			goto rx_processing_done;
>  		}
>
> -		dma_sync_single_for_cpu(&fep->pdev->dev,
> -					fec32_to_cpu(cbd_bufaddr),
> -					pkt_len,
> +		dma_sync_single_for_cpu(&fep->pdev->dev, dma, pkt_len,
>  					DMA_FROM_DEVICE);
>  		prefetch(page_address(page));
>
> @@ -1979,7 +1974,7 @@ static int fec_enet_rx(struct net_device *ndev, int budget)
>
>  	/* Make sure that AVB queues are processed first. */
>  	for (i = fep->num_rx_queues - 1; i >= 0; i--)
> -		done += fec_enet_rx_queue(ndev, i, budget - done);
> +		done += fec_enet_rx_queue(fep, i, budget - done);
>
>  	return done;
>  }
> --
> 2.34.1
>