@@ -71,6 +71,7 @@ struct css_task_iter {
extern struct file_system_type cgroup_fs_type;
extern struct cgroup_root cgrp_dfl_root;
extern struct css_set init_css_set;
+extern spinlock_t css_set_lock;
#define SUBSYS(_x) extern struct cgroup_subsys _x ## _cgrp_subsys;
#include <linux/cgroup_subsys.h>
@@ -159,6 +160,8 @@ void css_task_iter_start(struct cgroup_subsys_state *css, unsigned int flags,
struct css_task_iter *it);
struct task_struct *css_task_iter_next(struct css_task_iter *it);
void css_task_iter_end(struct css_task_iter *it);
+struct cgroup *task_cgroup_from_root(struct task_struct *task,
+ struct cgroup_root *root);
/**
* css_for_each_child - iterate through children of a css
@@ -388,7 +391,6 @@ static inline void cgroup_unlock(void)
* as locks used during the cgroup_subsys::attach() methods.
*/
#ifdef CONFIG_PROVE_RCU
-extern spinlock_t css_set_lock;
#define task_css_set_check(task, __c) \
rcu_dereference_check((task)->cgroups, \
rcu_read_lock_sched_held() || \
@@ -855,4 +857,6 @@ static inline void cgroup_bpf_put(struct cgroup *cgrp) {}
#endif /* CONFIG_CGROUP_BPF */
+struct cgroup *task_get_cgroup1_within_hierarchy(struct task_struct *tsk, int hierarchy_id);
+
#endif /* _LINUX_CGROUP_H */
@@ -164,7 +164,6 @@ struct cgroup_mgctx {
#define DEFINE_CGROUP_MGCTX(name) \
struct cgroup_mgctx name = CGROUP_MGCTX_INIT(name)
-extern spinlock_t css_set_lock;
extern struct cgroup_subsys *cgroup_subsys[];
extern struct list_head cgroup_roots;
@@ -1263,6 +1263,39 @@ int cgroup1_get_tree(struct fs_context *fc)
return ret;
}
+/**
+ * task_cgroup_id_within_hierarchy - Acquires the associated cgroup of a task
+ * within a specific cgroup1 hierarchy. The cgroup1 hierarchy is identified by
+ * its hierarchy ID.
+ * @tsk: The target task
+ * @hierarchy_id: The ID of a cgroup1 hierarchy
+ *
+ * On success, the cgroup is returned. On failure, ERR_PTR is returned.
+ * We limit it to cgroup1 only.
+ */
+struct cgroup *task_get_cgroup1_within_hierarchy(struct task_struct *tsk, int hierarchy_id)
+{
+ struct cgroup *cgrp = ERR_PTR(-ENOENT);
+ struct cgroup_root *root;
+
+ rcu_read_lock();
+ list_for_each_entry(root, &cgroup_roots, root_list) {
+ /* cgroup1 only*/
+ if (root == &cgrp_dfl_root)
+ continue;
+ if (root->hierarchy_id != hierarchy_id)
+ continue;
+ spin_lock_irq(&css_set_lock);
+ cgrp = task_cgroup_from_root(tsk, root);
+ if (!cgrp || !cgroup_tryget(cgrp))
+ cgrp = ERR_PTR(-ENOENT);
+ spin_unlock_irq(&css_set_lock);
+ break;
+ }
+ rcu_read_unlock();
+ return cgrp;
+}
+
static int __init cgroup1_wq_init(void)
{
/*
A new helper is added for cgroup1 hierarchy: - task_get_cgroup1_within_hierarchy Acquires the associated cgroup of a task within a specific cgroup1 hierarchy. The cgroup1 hierarchy is identified by its hierarchy ID. This helper function is added to facilitate the tracing of tasks within a particular container or cgroup dir in BPF programs. It's important to note that this helper is designed specifically for cgroup1 only. Signed-off-by: Yafang Shao <laoar.shao@gmail.com> --- include/linux/cgroup.h | 6 +++++- kernel/cgroup/cgroup-internal.h | 1 - kernel/cgroup/cgroup-v1.c | 33 +++++++++++++++++++++++++++++++++ 3 files changed, 38 insertions(+), 2 deletions(-)