Re: [PATCH bpf-next 3/9] bpf: Factor stackid_new_bucket from __bpf_get_stackid

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] The newly introduced `stackid_new_bucket` function accepts `trace` and `flags` parameters which are completely unused within its body.
--

--- Patch [3]: [PATCH bpf-next 3/9] bpf: Factor stackid_new_bucket from __bpf_get_stackid ---
commit cee0ea77a9c1144b54fb0472b1788623044b5650
Author: Jiri Olsa <jolsa@kernel.org>

bpf: Factor stackid_new_bucket from __bpf_get_stackid

This commit factors out the bucket allocation and initialization logic
from __bpf_get_stackid into a new stackid_new_bucket helper function.

> diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
> index 7bc2a966e3e81..48a2e28f0c68a 100644
> --- a/kernel/bpf/stackmap.c
> +++ b/kernel/bpf/stackmap.c
> @@ -559,31 +559,53 @@ static int stackid_fastpath(struct stackid *stackid, struct bpf_map *map,
>  	return -ENOENT;
>  }
>  
> +static struct stack_map_bucket *
> +stackid_new_bucket(struct stackid *stackid, struct bpf_map *map,
> +		   struct perf_callchain_entry *trace, u64 flags)

[Severity: Low]
Are the trace and flags parameters needed here?

Looking at the implementation of stackid_new_bucket() below, neither trace
nor flags are used anywhere in the function body. Could they be removed
from the function signature to clean up the API?

> +{
> +	struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);
> +	struct bpf_stack_build_id *id_offs;
> +	struct stack_map_bucket *bucket;
> +	u32 i;
> +
> +	bucket = (struct stack_map_bucket *) pcpu_freelist_pop(&smap->freelist);
> +	if (unlikely(!bucket))
> +		return NULL;
> +
> +	if (stack_map_use_build_id(map)) {
> +		id_offs = (struct bpf_stack_build_id *)bucket->data;
> +		for (i = 0; i < stackid->nr; i++)
> +			id_offs[i].ip = stackid->ips[i];
> +	} else {
> +		memcpy(bucket->data, stackid->ips, stackid->len);
> +	}
> +
> +	bucket->hash = stackid->hash;
> +	bucket->nr = stackid->nr;
> +	return bucket;
> +}

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260720085351.655075-1-jolsa@kernel.org?part=3