Re: [PATCH v2 08/23] mm: introduce BPF kfuncs to deal with memcg pointers

[Tejun Heo]

On Mon, Oct 27, 2025 at 04:17:11PM -0700, Roman Gushchin wrote:
> +__bpf_kfunc struct mem_cgroup *
> +bpf_get_mem_cgroup(struct cgroup_subsys_state *css)
> +{
> +	struct mem_cgroup *memcg = NULL;
> +	bool rcu_unlock = false;
> +
> +	if (!root_mem_cgroup)
> +		return NULL;
> +
> +	if (root_mem_cgroup->css.ss != css->ss) {
> +		struct cgroup *cgroup = css->cgroup;
> +		int ssid = root_mem_cgroup->css.ss->id;
> +
> +		rcu_read_lock();
> +		rcu_unlock = true;
> +		css = rcu_dereference_raw(cgroup->subsys[ssid]);

Would it make more sense to use cgroup_e_css()?

Thanks.

-- 
tejun