Re: [PATCH net-next 3/6] net: bcmgenet: add basic XDP support (PASS/DROP)

[Nicolai Buchwitz]

On 13.3.2026 23:48, Florian Fainelli wrote:
> On 3/13/26 02:20, Nicolai Buchwitz wrote:
> > Add XDP program attachment via ndo_bpf and execute XDP programs in the
> > RX path. Supported actions:
> >
> >    - XDP_PASS: build SKB from the (possibly modified) xdp_buff and 
> > pass
> >      to the network stack, handling xdp_adjust_head/tail correctly
> >    - XDP_DROP: return the page to page_pool, no SKB allocated
> >    - XDP_ABORTED: same as DROP with trace_xdp_exception
> >
> > XDP_TX and XDP_REDIRECT are not yet supported and will return
> > XDP_ABORTED.
> >
> > The XDP hook runs after the HW error checks but before SKB 
> > construction,
> > so dropped packets avoid all SKB allocation overhead.
> >
> > Advertise NETDEV_XDP_ACT_BASIC in xdp_features.
> >
> > Signed-off-by: Nicolai Buchwitz <nb@xxxxxxxxxxx>
> > ---
>
> [snip]
>
> > @@ -2345,12 +2397,6 @@ static unsigned int bcmgenet_desc_rx(struct 
> > bcmgenet_rx_ring *ring,
> >   		hard_start = page_address(rx_page) + rx_off;
> >   		status = (struct status_64 *)hard_start;
> >   		dma_length_status = status->length_status;
> > -		if (dev->features & NETIF_F_RXCSUM) {
> > -			rx_csum = (__force __be16)(status->rx_csum & 0xffff);
> > -			if (rx_csum) {
> > -				/* defer csum setup to after skb is built */
> > -			}
> > -		}
>
> Did you intend for that hunk to be deleted?

Yes, (kinda) intentional. Patch 1 moved the csum setup after SKB 
construction
(since we no longer have an SKB at that point), but left the early read
as a dead no-op - patch 3 then removed it. I'll clean this up in v2 by
dropping the dead block directly in patch 1 instead.

Nicolai