Subject: Re: [PATCH bpf v3 2/2] selftests/bpf: Test TCP_NODELAY in TCP hdr opt callbacks

From: Martin KaFai Lau <[email-masked]>
Date: Fri, 17 Apr 2026 09:25:18 -0700

On Fri, Apr 17, 2026 at 05:20:35PM +0800, KaFai Wan wrote:
> diff --git a/tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c b/tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c
> index 56685fc03c7e..7b9dbbb84316 100644
> --- a/tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c
> +++ b/tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c
> @@ -461,7 +461,7 @@ static void misc(void)
>  	const unsigned int nr_data = 2;
>  	struct bpf_link *link;
>  	struct sk_fds sk_fds;
> -	int i, ret;
> +	int i, ret, true_val = 1;
>  
>  	lport_linum_map_fd = bpf_map__fd(misc_skel->maps.lport_linum_map);
>  
> @@ -477,6 +477,10 @@ static void misc(void)
>  		return;
>  	}
>  
> +	ret = setsockopt(sk_fds.active_fd, SOL_TCP, TCP_NODELAY, &true_val, sizeof(true_val));

Same comment as in v2. Why this setsockopt is needed?
The setsockopt in userspace is unnecessary. In the future,
we may need to understand why it is needed here in the first place.