On Fri, Apr 21, 2023 at 05:04:02PM +0800, Feng zhou wrote:
> From: Feng Zhou <zhoufeng.zf@xxxxxxxxxxxxx>
>
> Add a kfunc that's similar to the bpf_current_task_under_cgroup.
> The difference is that it is a designated task.
>
> When hook sched related functions, sometimes it is necessary to
> specify a task instead of the current task.
>
> Signed-off-by: Feng Zhou <zhoufeng.zf@xxxxxxxxxxxxx>
> ---
> kernel/bpf/helpers.c | 19 +++++++++++++++++++
> 1 file changed, 19 insertions(+)
>
> diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
> index 00e5fb0682ac..88e3247b5c44 100644
> --- a/kernel/bpf/helpers.c
> +++ b/kernel/bpf/helpers.c
> @@ -2142,6 +2142,24 @@ __bpf_kfunc struct cgroup *bpf_cgroup_from_id(u64 cgid)
> return NULL;
> return cgrp;
> }
> +
> +/**
> + * bpf_task_under_cgroup - Check whether the task is a given subset of the
> + * cgroup2 hierarchy. The cgroup2 to test is assigned by cgrp.
That doesn't read right.
> + * @cgrp: assigned cgrp.
> + * @task: assigned task.
This is also wrong.
Please copy paste from task_under_cgroup_hierarchy.
> + */
> +__bpf_kfunc int bpf_task_under_cgroup(struct cgroup *cgrp,
> + struct task_struct *task)
return type needs to be 'long'. 'int' might have issues.
Also the args should be task, cgrp to match task_under_cgroup_hierarchy.
> +{
> + if (unlikely(!cgrp))
> + return -EAGAIN;
> +
> + if (unlikely(!task))
> + return -ENOENT;
Please do
if (unlikely(!cgrp || !task))
return -EINVAL;
> +
> + return task_under_cgroup_hierarchy(task, cgrp);
> +}
> #endif /* CONFIG_CGROUPS */
>
> /**
> @@ -2341,6 +2359,7 @@ BTF_ID_FLAGS(func, bpf_cgroup_acquire, KF_ACQUIRE | KF_RCU | KF_RET_NULL)
> BTF_ID_FLAGS(func, bpf_cgroup_release, KF_RELEASE)
> BTF_ID_FLAGS(func, bpf_cgroup_ancestor, KF_ACQUIRE | KF_RCU | KF_RET_NULL)
> BTF_ID_FLAGS(func, bpf_cgroup_from_id, KF_ACQUIRE | KF_RET_NULL)
> +BTF_ID_FLAGS(func, bpf_task_under_cgroup, KF_RCU)
> #endif
> BTF_ID_FLAGS(func, bpf_task_from_pid, KF_ACQUIRE | KF_RET_NULL)
> BTF_SET8_END(generic_btf_ids)
> --
> 2.20.1
>
