On 13/06/2023 11.18, [email protected] wrote:
> Fix the following coccicheck warning:
>
> samples/bpf/xdp1_kern.c:50: Unneeded variable: "rc".
>
> Signed-off-by: Mingtong Bao <[email protected]>
> ---
> samples/bpf/xdp1_kern.c | 11 +++++------
> 1 file changed, 5 insertions(+), 6 deletions(-)
>
> diff --git a/samples/bpf/xdp1_kern.c b/samples/bpf/xdp1_kern.c
> index d91f27cbcfa9..d426df4a9d6b 100644
> --- a/samples/bpf/xdp1_kern.c
> +++ b/samples/bpf/xdp1_kern.c
> @@ -47,18 +47,17 @@ int xdp_prog1(struct xdp_md *ctx)
> void *data_end = &pkt[XDPBUFSIZE-1];
> void *data = pkt;
> struct ethhdr *eth = data;
> - int rc = XDP_DROP;
> long *value;
> u16 h_proto;
> u64 nh_off;
> u32 ipproto;
>
> if (bpf_xdp_load_bytes(ctx, 0, pkt, sizeof(pkt)))
> - return rc;
> + return XDP_DROP;
IMHO for these error cases, we should return XDP_ABORTED instead.
This will make is easier to debug, e.g. with xdpdump[1] or xdp-monitor[2].
Reminder that drivers (usually) have a tracepoint for XDP_ABORTED
(code see trace_xdp_exception).
[1] https://github.com/xdp-project/xdp-tools/tree/master/xdp-dump
[2] https://github.com/xdp-project/xdp-tools/tree/master/xdp-monitor
>
> nh_off = sizeof(*eth);
> if (data + nh_off > data_end)
> - return rc;
> + return XDP_DROP;
>
> h_proto = eth->h_proto;
>
> @@ -69,7 +68,7 @@ int xdp_prog1(struct xdp_md *ctx)
> vhdr = data + nh_off;
> nh_off += sizeof(struct vlan_hdr);
> if (data + nh_off > data_end)
> - return rc;
> + return XDP_DROP;
Use XDP_ABORTED
> h_proto = vhdr->h_vlan_encapsulated_proto;
> }
> /* Handle double VLAN tagged packet */
> @@ -79,7 +78,7 @@ int xdp_prog1(struct xdp_md *ctx)
> vhdr = data + nh_off;
> nh_off += sizeof(struct vlan_hdr);
> if (data + nh_off > data_end)
> - return rc;
> + return XDP_DROP;
Use XDP_ABORTED
> h_proto = vhdr->h_vlan_encapsulated_proto;
> }
>
> @@ -94,7 +93,7 @@ int xdp_prog1(struct xdp_md *ctx)
> if (value)
> *value += 1;
>
> - return rc;
> + return XDP_DROP;
This is correct. Here use XDP_DROP.
> }
>
> char _license[] SEC("license") = "GPL";