Re: [net-next RFC v3 4/7] net: ravb: Refactor GbEth RX code path

[Sergey Shtylyov <s.shtylyov@omp.ru>]

On 4/15/24 12:48 PM, Paul Barker wrote:

> We can reduce code duplication in ravb_rx_gbeth() and add comments to
> make the code flow easier to understand.
> 
> Signed-off-by: Paul Barker <paul.barker.ct@bp.renesas.com>
> ---
>  drivers/net/ethernet/renesas/ravb_main.c | 70 ++++++++++++------------
>  1 file changed, 35 insertions(+), 35 deletions(-)
> 
> diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
> index baa01bd81f2d..12618171f6d5 100644
> --- a/drivers/net/ethernet/renesas/ravb_main.c
> +++ b/drivers/net/ethernet/renesas/ravb_main.c
> @@ -818,47 +818,47 @@ static int ravb_rx_gbeth(struct net_device *ndev, int budget, int q)
>  				stats->rx_missed_errors++;
>  		} else {
>  			die_dt = desc->die_dt & 0xF0;
> -			switch (die_dt) {
> -			case DT_FSINGLE:
> -				skb = ravb_get_skb_gbeth(ndev, entry, desc);
> +			skb = ravb_get_skb_gbeth(ndev, entry, desc);
> +			if (die_dt == DT_FSINGLE || die_dt == DT_FSTART) {

   No, please keep using *switch* statement here...

> +				/* Start of packet:
> +				 * Set initial data length.
> +				 */
>  				skb_put(skb, desc_len);
> +
> +				/* Save this SKB if the packet spans multiple
> +				 * descriptors.
> +				 */
> +				if (die_dt == DT_FSTART)
> +					priv->rx_1st_skb = skb;

   Hm, looks like we can do that under *case* DT_FSTART: and do
a fallthru to *case* DT_FSINGLE: after that...

> +			} else {
> +				/* Continuing a packet:
> +				 * Move data into the saved SKB.
> +				 */
> +				skb_copy_to_linear_data_offset(priv->rx_1st_skb,
> +							       priv->rx_1st_skb->len,
> +							       skb->data,
> +							       desc_len);
> +				skb_put(priv->rx_1st_skb, desc_len);
> +				dev_kfree_skb(skb);
> +
> +				/* Set skb to point at the whole packet so that
> +				 * we only need one code path for finishing a
> +				 * packet.
> +				 */
> +				skb = priv->rx_1st_skb;
> +			}
> +
> +			if (die_dt == DT_FSINGLE || die_dt == DT_FEND) {

   Again, keep using *switch*, please...

> +				/* Finishing a packet:
> +				 * Determine protocol & checksum, hand off to
> +				 * NAPI and update our stats.
> +				 */
>  				skb->protocol = eth_type_trans(skb, ndev);
>  				if (ndev->features & NETIF_F_RXCSUM)
>  					ravb_rx_csum_gbeth(skb);
> +				stats->rx_bytes += skb->len;
>  				napi_gro_receive(&priv->napi[q], skb);
>  				rx_packets++;
[...]

MBR, Sergey