1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __CGROUP_INTERNAL_H
3 #define __CGROUP_INTERNAL_H
5 #include <linux/cgroup.h>
6 #include <linux/kernfs.h>
7 #include <linux/workqueue.h>
8 #include <linux/list.h>
9 #include <linux/refcount.h>
11 struct cgroup_pidlist;
13 struct cgroup_file_ctx {
14 struct cgroup_namespace *ns;
22 struct css_task_iter iter;
26 struct cgroup_pidlist *pidlist;
31 * A cgroup can be associated with multiple css_sets as different tasks may
32 * belong to different cgroups on different hierarchies. In the other
33 * direction, a css_set is naturally associated with multiple cgroups.
34 * This M:N relationship is represented by the following link structure
35 * which exists for each association and allows traversing the associations
38 struct cgrp_cset_link {
39 /* the cgroup and css_set this link associates */
43 /* list of cgrp_cset_links anchored at cgrp->cset_links */
44 struct list_head cset_link;
46 /* list of cgrp_cset_links anchored at css_set->cgrp_links */
47 struct list_head cgrp_link;
50 /* used to track tasks and csets during migration */
51 struct cgroup_taskset {
52 /* the src and dst cset list running through cset->mg_node */
53 struct list_head src_csets;
54 struct list_head dst_csets;
56 /* the number of tasks in the set */
59 /* the subsys currently being processed */
63 * Fields for cgroup_taskset_*() iteration.
65 * Before migration is committed, the target migration tasks are on
66 * ->mg_tasks of the csets on ->src_csets. After, on ->mg_tasks of
67 * the csets on ->dst_csets. ->csets point to either ->src_csets
68 * or ->dst_csets depending on whether migration is committed.
70 * ->cur_csets and ->cur_task point to the current task position
73 struct list_head *csets;
74 struct css_set *cur_cset;
75 struct task_struct *cur_task;
78 /* migration context also tracks preloading */
81 * Preloaded source and destination csets. Used to guarantee
82 * atomic success or failure on actual migration.
84 struct list_head preloaded_src_csets;
85 struct list_head preloaded_dst_csets;
87 /* tasks and csets to migrate */
88 struct cgroup_taskset tset;
90 /* subsystems affected by migration */
94 #define CGROUP_TASKSET_INIT(tset) \
96 .src_csets = LIST_HEAD_INIT(tset.src_csets), \
97 .dst_csets = LIST_HEAD_INIT(tset.dst_csets), \
98 .csets = &tset.src_csets, \
101 #define CGROUP_MGCTX_INIT(name) \
103 LIST_HEAD_INIT(name.preloaded_src_csets), \
104 LIST_HEAD_INIT(name.preloaded_dst_csets), \
105 CGROUP_TASKSET_INIT(name.tset), \
108 #define DEFINE_CGROUP_MGCTX(name) \
109 struct cgroup_mgctx name = CGROUP_MGCTX_INIT(name)
111 struct cgroup_sb_opts {
115 bool cpuset_clone_children;
117 /* User explicitly requested empty subsystem */
121 extern struct mutex cgroup_mutex;
122 extern spinlock_t css_set_lock;
123 extern struct cgroup_subsys *cgroup_subsys[];
124 extern struct list_head cgroup_roots;
126 /* iterate across the hierarchies */
127 #define for_each_root(root) \
128 list_for_each_entry((root), &cgroup_roots, root_list)
131 * for_each_subsys - iterate all enabled cgroup subsystems
132 * @ss: the iteration cursor
133 * @ssid: the index of @ss, CGROUP_SUBSYS_COUNT after reaching the end
135 #define for_each_subsys(ss, ssid) \
136 for ((ssid) = 0; (ssid) < CGROUP_SUBSYS_COUNT && \
137 (((ss) = cgroup_subsys[ssid]) || true); (ssid)++)
139 static inline bool cgroup_is_dead(const struct cgroup *cgrp)
141 return !(cgrp->self.flags & CSS_ONLINE);
144 static inline bool notify_on_release(const struct cgroup *cgrp)
146 return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
149 void put_css_set_locked(struct css_set *cset);
151 static inline void put_css_set(struct css_set *cset)
156 * Ensure that the refcount doesn't hit zero while any readers
157 * can see it. Similar to atomic_dec_and_lock(), but for an
160 if (refcount_dec_not_one(&cset->refcount))
163 spin_lock_irqsave(&css_set_lock, flags);
164 put_css_set_locked(cset);
165 spin_unlock_irqrestore(&css_set_lock, flags);
169 * refcounted get/put for css_set objects
171 static inline void get_css_set(struct css_set *cset)
173 refcount_inc(&cset->refcount);
176 bool cgroup_ssid_enabled(int ssid);
177 bool cgroup_on_dfl(const struct cgroup *cgrp);
178 bool cgroup_is_thread_root(struct cgroup *cgrp);
179 bool cgroup_is_threaded(struct cgroup *cgrp);
181 struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root);
182 struct cgroup *task_cgroup_from_root(struct task_struct *task,
183 struct cgroup_root *root);
184 struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn, bool drain_offline);
185 void cgroup_kn_unlock(struct kernfs_node *kn);
186 int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
187 struct cgroup_namespace *ns);
189 void cgroup_free_root(struct cgroup_root *root);
190 void init_cgroup_root(struct cgroup_root *root, struct cgroup_sb_opts *opts);
191 int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask, int ref_flags);
192 int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask);
193 struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags,
194 struct cgroup_root *root, unsigned long magic,
195 struct cgroup_namespace *ns);
197 int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp);
198 void cgroup_migrate_finish(struct cgroup_mgctx *mgctx);
199 void cgroup_migrate_add_src(struct css_set *src_cset, struct cgroup *dst_cgrp,
200 struct cgroup_mgctx *mgctx);
201 int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx);
202 int cgroup_migrate(struct task_struct *leader, bool threadgroup,
203 struct cgroup_mgctx *mgctx);
205 int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader,
207 struct task_struct *cgroup_procs_write_start(char *buf, bool threadgroup)
208 __acquires(&cgroup_threadgroup_rwsem);
209 void cgroup_procs_write_finish(struct task_struct *task)
210 __releases(&cgroup_threadgroup_rwsem);
212 void cgroup_lock_and_drain_offline(struct cgroup *cgrp);
214 int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode);
215 int cgroup_rmdir(struct kernfs_node *kn);
216 int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node,
217 struct kernfs_root *kf_root);
219 int cgroup_task_count(const struct cgroup *cgrp);
224 extern const struct proc_ns_operations cgroupns_operations;
229 extern struct cftype cgroup1_base_files[];
230 extern const struct file_operations proc_cgroupstats_operations;
231 extern struct kernfs_syscall_ops cgroup1_kf_syscall_ops;
233 bool cgroup1_ssid_disabled(int ssid);
234 void cgroup1_pidlist_destroy_all(struct cgroup *cgrp);
235 void cgroup1_release_agent(struct work_struct *work);
236 void cgroup1_check_for_release(struct cgroup *cgrp);
237 struct dentry *cgroup1_mount(struct file_system_type *fs_type, int flags,
238 void *data, unsigned long magic,
239 struct cgroup_namespace *ns);
241 #endif /* __CGROUP_INTERNAL_H */