Subject: Re: [PATCH bpf-next/net v6 2/3] selftests/bpf: Add getsockopt to inspect mptcp subflow

From: Martin KaFai Lau <[email-masked]>
Date: Fri, 13 Sep 2024 17:11:17 -0700

On 9/11/24 8:16 AM, Matthieu Baerts (NGI0) wrote:
> diff --git a/tools/testing/selftests/bpf/progs/mptcp_bpf.h b/tools/testing/selftests/bpf/progs/mptcp_bpf.h
> new file mode 100644
> index 000000000000..179b74c1205f
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/mptcp_bpf.h
> @@ -0,0 +1,42 @@
> +/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
> +#ifndef __MPTCP_BPF_H__
> +#define __MPTCP_BPF_H__
> +
> +#include "bpf_experimental.h"
> +
> +/* list helpers from include/linux/list.h */
> +static inline int list_is_head(const struct list_head *list,
> +			       const struct list_head *head)
> +{
> +	return list == head;
> +}
> +
> +#define list_entry(ptr, type, member)					\
> +	container_of(ptr, type, member)
> +
> +#define list_first_entry(ptr, type, member)				\
> +	list_entry((ptr)->next, type, member)
> +
> +#define list_next_entry(pos, member)					\
> +	list_entry((pos)->member.next, typeof(*(pos)), member)
> +
> +#define list_entry_is_head(pos, head, member)				\
> +	list_is_head(&pos->member, (head))
> +
> +/* small difference: 'cond_break' has been added in the conditions */
> +#define list_for_each_entry(pos, head, member)				\
> +	for (pos = list_first_entry(head, typeof(*pos), member);	\
> +	     cond_break, !list_entry_is_head(pos, head, member);	\

It probably should use can_loop.
See commit ba39486d2c43 ("bpf: make list_for_each_entry portable")