Subject: Re: [PATCH bpf-next v5 2/7] bpf: Support associating BPF program with struct_ops

From: Martin KaFai Lau <[email-masked]>
Date: Wed, 5 Nov 2025 16:57:44 -0800

On 11/4/25 9:26 AM, Amery Hung wrote:
> +void *bpf_prog_get_assoc_struct_ops(const struct bpf_prog_aux *aux)
> +{
> +	struct bpf_map *st_ops_assoc = READ_ONCE(aux->st_ops_assoc);
> +	struct bpf_struct_ops_map *st_map;
> +
> +	if (!st_ops_assoc || st_ops_assoc == BPF_PTR_POISON)
> +		return NULL;
> +
> +	st_map = (struct bpf_struct_ops_map *)st_ops_assoc;
> +
> +	if (smp_load_acquire(&st_map->kvalue.common.state) == BPF_STRUCT_OPS_STATE_INIT) {
> +		bpf_map_put(st_ops_assoc);

hmm... why bpf_map_put is needed?

Should the state be checked only once during assoc time instead of 
checking it every time bpf_prog_get_assoc_struct_ops is called?

> +		return NULL;
> +	}
> +
> +	return &st_map->kvalue.data;
> +}