Re: [PATCH bpf-next v2 2/3] selftests/bpf: Add multi_st_ops that supports multiple instances

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

On 8/6/25 9:25 AM, Amery Hung wrote:
> +int bpf_kfunc_multi_st_ops_test_1(struct st_ops_args *args, u32 id)
> +{
> +	struct bpf_testmod_multi_st_ops *st_ops;
> +	unsigned long flags;
> +	int ret = -1;
> +
> +	spin_lock_irqsave(&multi_st_ops_lock, flags);
> +	st_ops = multi_st_ops_find_nolock(id);
> +	if (st_ops)
> +		ret = st_ops->test_1(args);

test_1 cannot be NULL,

> +	spin_unlock_irqrestore(&multi_st_ops_lock, flags);
> +
> +	return ret;
> +}
> +
> +static int multi_st_ops_reg(void *kdata, struct bpf_link *link)
> +{
> +	struct bpf_testmod_multi_st_ops *st_ops =
> +		(struct bpf_testmod_multi_st_ops *)kdata;
> +	unsigned long flags;
> +	int err = 0;
> +	u32 id;
> +

so I added a "if (!st_ops->test_1)" test.

> +	id = bpf_struct_ops_id(kdata);
> +
> +	spin_lock_irqsave(&multi_st_ops_lock, flags);
> +	if (multi_st_ops_find_nolock(id)) {
> +		pr_err("multi_st_ops(id:%d) has already been registered\n", id);
> +		err = -EEXIST;
> +		goto unlock;
> +	}
> +
> +	st_ops->id = id;
> +	hlist_add_head(&st_ops->node, &multi_st_ops_list);
> +unlock:
> +	spin_unlock_irqrestore(&multi_st_ops_lock, flags);
> +
> +	return err;
> +}


[ ... ]

> diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.h b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.h
> index c9fab51f16e2..b8001ba7c368 100644
> --- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.h
> +++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.h
> @@ -116,4 +116,12 @@ struct bpf_testmod_st_ops {
>   	struct module *owner;
>   };
>   
> +#define BPF_TESTMOD_NAME_SZ 16

Not sure why it is here. I don't see it is used, so removed.