Introducing new kfuncs:
- bpf_cgroup_id_from_task_within_controller
Retrieves the cgroup ID from a task within a specific cgroup controller.
- bpf_cgroup_acquire_from_id_within_controller
Acquires the cgroup from a cgroup ID within a specific cgroup controller.
- bpf_cgroup_ancestor_id_from_task_within_controller
Retrieves the ancestor cgroup ID from a task within a specific cgroup
controller.
These functions eliminate the need to consider cgroup hierarchies,
regardless of whether they involve cgroup1 or cgroup2.
Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
---
kernel/bpf/helpers.c | 70 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 70 insertions(+)
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index bb521b181cc3..1316b5fda349 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -2219,6 +2219,73 @@ __bpf_kfunc long bpf_task_under_cgroup(struct task_struct *task,
rcu_read_unlock();
return ret;
}
+
+/**
+ * bpf_cgroup_id_from_task_within_controller - To get the associated cgroup_id from
+ * a task within a specific cgroup controller.
+ * @task: The target task
+ * @ssid: The id of cgroup controller, e.g. cpu_cgrp_id, memory_cgrp_id and etc.
+ */
+__bpf_kfunc u64 bpf_cgroup_id_from_task_within_controller(struct task_struct *task, int ssid)
+{
+ struct cgroup *cgroup;
+ int id = 0;
+
+ rcu_read_lock();
+ cgroup = task_cgroup(task, ssid);
+ if (!cgroup)
+ goto out;
+ id = cgroup_id(cgroup);
+
+out:
+ rcu_read_unlock();
+ return id;
+}
+
+/**
+ * bpf_cgroup_id_from_task_within_controller - To get the associated cgroup_id from
+ * a task within a specific cgroup controller.
+ * @task: The target task
+ * @ssid: The id of cgroup subsystem, e.g. cpu_cgrp_id, memory_cgrp_id and etc.
+ * @level: The level of ancestor to look up
+ */
+__bpf_kfunc u64 bpf_cgroup_ancestor_id_from_task_within_controller(struct task_struct *task,
+ int ssid, int level)
+{
+ struct cgroup *cgrp, *ancestor;
+ int id = 0;
+
+ rcu_read_lock();
+ cgrp = task_cgroup(task, ssid);
+ if (!cgrp)
+ goto out;
+ ancestor = cgroup_ancestor(cgrp, level);
+ if (ancestor)
+ id = cgroup_id(ancestor);
+
+out:
+ rcu_read_unlock();
+ return id;
+}
+
+/**
+ * bpf_cgroup_acquire_from_id_within_controller - To acquire the cgroup from a
+ * cgroup id within specific cgroup controller. A cgroup acquired by this kfunc
+ * which is not stored in a map as a kptr, must be released by calling
+ * bpf_cgroup_release().
+ * @cgid: cgroup id
+ * @ssid: The id of a cgroup controller, e.g. cpu_cgrp_id, memory_cgrp_id and etc.
+ */
+__bpf_kfunc struct cgroup *bpf_cgroup_acquire_from_id_within_controller(u64 cgid, int ssid)
+{
+ struct cgroup *cgrp;
+
+ cgrp = cgroup_get_from_id_within_subsys(cgid, ssid);
+ if (IS_ERR(cgrp))
+ return NULL;
+ return cgrp;
+}
+
#endif /* CONFIG_CGROUPS */
/**
@@ -2525,6 +2592,9 @@ 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)
+BTF_ID_FLAGS(func, bpf_cgroup_id_from_task_within_controller)
+BTF_ID_FLAGS(func, bpf_cgroup_ancestor_id_from_task_within_controller)
+BTF_ID_FLAGS(func, bpf_cgroup_acquire_from_id_within_controller, KF_ACQUIRE | KF_RET_NULL)
#endif
BTF_ID_FLAGS(func, bpf_task_from_pid, KF_ACQUIRE | KF_RET_NULL)
BTF_ID_FLAGS(func, bpf_throw)
--
2.30.1 (Apple Git-130)
