Commit b5ad4cdc authored by Feng Zhou's avatar Feng Zhou Committed by Alexei Starovoitov
Browse files

bpf: Add bpf_task_under_cgroup() kfunc 



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: default avatarFeng Zhou <zhoufeng.zf@bytedance.com>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20230506031545.35991-2-zhoufeng.zf@bytedance.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent f4dea968

kernel/bpf/helpers.c

+17 −0
Original line number Diff line number Diff line
@@ -2149,6 +2149,22 @@ __bpf_kfunc struct cgroup *bpf_cgroup_from_id(u64 cgid) 
		return NULL;

	return cgrp;

}



/**

 * bpf_task_under_cgroup - wrap task_under_cgroup_hierarchy() as a kfunc, test

 * task's membership of cgroup ancestry.

 * @task: the task to be tested

 * @ancestor: possible ancestor of @task's cgroup

 *

 * Tests whether @task's default cgroup hierarchy is a descendant of @ancestor.

 * It follows all the same rules as cgroup_is_descendant, and only applies

 * to the default hierarchy.

 */

__bpf_kfunc long bpf_task_under_cgroup(struct task_struct *task,

				       struct cgroup *ancestor)

{

	return task_under_cgroup_hierarchy(task, ancestor);

}

#endif /* CONFIG_CGROUPS */



/**
@@ -2400,6 +2416,7 @@ 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)