Re: [PATCH bpf-next v7 4/5] selftests/bpf: Support non-linear flag in test loader

[Martin KaFai Lau <martin.lau@linux.dev>]

On 10/9/25 7:02 AM, Paul Chaignon wrote:
> @@ -633,6 +635,11 @@ static int parse_test_spec(struct test_loader *tester,
>   					      &spec->unpriv.stdout);
>   			if (err)
>   				goto cleanup;
> +		} else if (str_has_pfx(s, TEST_TAG_LINEAR_SIZE)) {
> +			val = s + sizeof(TEST_TAG_LINEAR_SIZE) - 1;
> +			err = parse_int(val, &spec->linear_sz, "test linear size");
> +			if (err)
> +				goto cleanup;
>   		}
>   	}
>   
> @@ -1007,10 +1014,11 @@ static bool is_unpriv_capable_map(struct bpf_map *map)
>   	}
>   }
>   
> -static int do_prog_test_run(int fd_prog, int *retval, bool empty_opts)
> +static int do_prog_test_run(int fd_prog, int *retval, bool empty_opts, int linear_sz)
>   {
>   	__u8 tmp_out[TEST_DATA_LEN << 2] = {};
>   	__u8 tmp_in[TEST_DATA_LEN] = {};
> +	struct __sk_buff ctx = {};

since it needs a re-spin...

not all prog type uses "struct __sk_buff". linear_sz could be useful for xdp 
also but it also needs a different struct. This is pretty much "tc" and 
"cgroup_skb" only for now. How about error out earlier in the parse_test_spec? I 
think the bpf_program__type() should already be available at the parse_test_spec().

>   	int err, saved_errno;
>   	LIBBPF_OPTS(bpf_test_run_opts, topts,
>   		.data_in = tmp_in,
> @@ -1020,6 +1028,12 @@ static int do_prog_test_run(int fd_prog, int *retval, bool empty_opts)
>   		.repeat = 1,
>   	);
>   
> +	if (linear_sz) {
> +		ctx.data_end = linear_sz;
> +		topts.ctx_in = &ctx;
> +		topts.ctx_size_in = sizeof(ctx);
> +	}
> +