1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __CGROUP_INTERNAL_H
3#define __CGROUP_INTERNAL_H
4
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>
10#include <linux/fs_parser.h>
11
12#define TRACE_CGROUP_PATH_LEN 1024
13extern spinlock_t trace_cgroup_path_lock;
14extern char trace_cgroup_path[TRACE_CGROUP_PATH_LEN];
15extern void __init enable_debug_cgroup(void);
16
17/*
18 * cgroup_path() takes a spin lock. It is good practice not to take
19 * spin locks within trace point handlers, as they are mostly hidden
20 * from normal view. As cgroup_path() can take the kernfs_rename_lock
21 * spin lock, it is best to not call that function from the trace event
22 * handler.
23 *
24 * Note: trace_cgroup_##type##_enabled() is a static branch that will only
25 * be set when the trace event is enabled.
26 */
27#define TRACE_CGROUP_PATH(type, cgrp, ...) \
28 do { \
29 if (trace_cgroup_##type##_enabled()) { \
30 unsigned long flags; \
31 spin_lock_irqsave(&trace_cgroup_path_lock, \
32 flags); \
33 cgroup_path(cgrp, trace_cgroup_path, \
34 TRACE_CGROUP_PATH_LEN); \
35 trace_cgroup_##type(cgrp, trace_cgroup_path, \
36 ##__VA_ARGS__); \
37 spin_unlock_irqrestore(&trace_cgroup_path_lock, \
38 flags); \
39 } \
40 } while (0)
41
42/*
43 * The cgroup filesystem superblock creation/mount context.
44 */
45struct cgroup_fs_context {
46 struct kernfs_fs_context kfc;
47 struct cgroup_root *root;
48 struct cgroup_namespace *ns;
49 unsigned int flags; /* CGRP_ROOT_* flags */
50
51 /* cgroup1 bits */
52 bool cpuset_clone_children;
53 bool none; /* User explicitly requested empty subsystem */
54 bool all_ss; /* Seen 'all' option */
55 u16 subsys_mask; /* Selected subsystems */
56 char *name; /* Hierarchy name */
57 char *release_agent; /* Path for release notifications */
58};
59
60static inline struct cgroup_fs_context *cgroup_fc2context(struct fs_context *fc)
61{
62 struct kernfs_fs_context *kfc = fc->fs_private;
63
64 return container_of(kfc, struct cgroup_fs_context, kfc);
65}
66
67struct cgroup_pidlist;
68
69struct cgroup_file_ctx {
70 struct cgroup_namespace *ns;
71
72 struct {
73 void *trigger;
74 } psi;
75
76 struct {
77 bool started;
78 struct css_task_iter iter;
79 } procs;
80
81 struct {
82 struct cgroup_pidlist *pidlist;
83 } procs1;
84
85 struct cgroup_of_peak peak;
86};
87
88/*
89 * A cgroup can be associated with multiple css_sets as different tasks may
90 * belong to different cgroups on different hierarchies. In the other
91 * direction, a css_set is naturally associated with multiple cgroups.
92 * This M:N relationship is represented by the following link structure
93 * which exists for each association and allows traversing the associations
94 * from both sides.
95 */
96struct cgrp_cset_link {
97 /* the cgroup and css_set this link associates */
98 struct cgroup *cgrp;
99 struct css_set *cset;
100
101 /* list of cgrp_cset_links anchored at cgrp->cset_links */
102 struct list_head cset_link;
103
104 /* list of cgrp_cset_links anchored at css_set->cgrp_links */
105 struct list_head cgrp_link;
106};
107
108/* used to track tasks and csets during migration */
109struct cgroup_taskset {
110 /* the src and dst cset list running through cset->mg_node */
111 struct list_head src_csets;
112 struct list_head dst_csets;
113
114 /* the number of tasks in the set */
115 int nr_tasks;
116
117 /* the subsys currently being processed */
118 int ssid;
119
120 /*
121 * Fields for cgroup_taskset_*() iteration.
122 *
123 * Before migration is committed, the target migration tasks are on
124 * ->mg_tasks of the csets on ->src_csets. After, on ->mg_tasks of
125 * the csets on ->dst_csets. ->csets point to either ->src_csets
126 * or ->dst_csets depending on whether migration is committed.
127 *
128 * ->cur_csets and ->cur_task point to the current task position
129 * during iteration.
130 */
131 struct list_head *csets;
132 struct css_set *cur_cset;
133 struct task_struct *cur_task;
134};
135
136/* migration context also tracks preloading */
137struct cgroup_mgctx {
138 /*
139 * Preloaded source and destination csets. Used to guarantee
140 * atomic success or failure on actual migration.
141 */
142 struct list_head preloaded_src_csets;
143 struct list_head preloaded_dst_csets;
144
145 /* tasks and csets to migrate */
146 struct cgroup_taskset tset;
147
148 /* subsystems affected by migration */
149 u16 ss_mask;
150};
151
152#define CGROUP_TASKSET_INIT(tset) \
153{ \
154 .src_csets = LIST_HEAD_INIT(tset.src_csets), \
155 .dst_csets = LIST_HEAD_INIT(tset.dst_csets), \
156 .csets = &tset.src_csets, \
157}
158
159#define CGROUP_MGCTX_INIT(name) \
160{ \
161 LIST_HEAD_INIT(name.preloaded_src_csets), \
162 LIST_HEAD_INIT(name.preloaded_dst_csets), \
163 CGROUP_TASKSET_INIT(name.tset), \
164}
165
166#define DEFINE_CGROUP_MGCTX(name) \
167 struct cgroup_mgctx name = CGROUP_MGCTX_INIT(name)
168
169extern struct cgroup_subsys *cgroup_subsys[];
170extern struct list_head cgroup_roots;
171extern bool cgrp_dfl_visible;
172
173/* iterate across the hierarchies */
174#define for_each_root(root) \
175 list_for_each_entry_rcu((root), &cgroup_roots, root_list, \
176 lockdep_is_held(&cgroup_mutex))
177
178/**
179 * for_each_subsys - iterate all enabled cgroup subsystems
180 * @ss: the iteration cursor
181 * @ssid: the index of @ss, CGROUP_SUBSYS_COUNT after reaching the end
182 */
183#define for_each_subsys(ss, ssid) \
184 for ((ssid) = 0; (ssid) < CGROUP_SUBSYS_COUNT && \
185 (((ss) = cgroup_subsys[ssid]) || true); (ssid)++)
186
187static inline bool cgroup_is_dead(const struct cgroup *cgrp)
188{
189 return !(cgrp->self.flags & CSS_ONLINE);
190}
191
192static inline bool notify_on_release(const struct cgroup *cgrp)
193{
194 return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
195}
196
197void put_css_set_locked(struct css_set *cset);
198
199static inline void put_css_set(struct css_set *cset)
200{
201 unsigned long flags;
202
203 /*
204 * Ensure that the refcount doesn't hit zero while any readers
205 * can see it. Similar to atomic_dec_and_lock(), but for an
206 * rwlock
207 */
208 if (refcount_dec_not_one(r: &cset->refcount))
209 return;
210
211 spin_lock_irqsave(&css_set_lock, flags);
212 put_css_set_locked(cset);
213 spin_unlock_irqrestore(lock: &css_set_lock, flags);
214}
215
216/*
217 * refcounted get/put for css_set objects
218 */
219static inline void get_css_set(struct css_set *cset)
220{
221 refcount_inc(r: &cset->refcount);
222}
223
224bool cgroup_ssid_enabled(int ssid);
225bool cgroup_on_dfl(const struct cgroup *cgrp);
226
227struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root);
228struct cgroup *task_cgroup_from_root(struct task_struct *task,
229 struct cgroup_root *root);
230struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn, bool drain_offline);
231void cgroup_kn_unlock(struct kernfs_node *kn);
232int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
233 struct cgroup_namespace *ns);
234
235void cgroup_favor_dynmods(struct cgroup_root *root, bool favor);
236void cgroup_free_root(struct cgroup_root *root);
237void init_cgroup_root(struct cgroup_fs_context *ctx);
238int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask);
239int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask);
240int cgroup_do_get_tree(struct fs_context *fc);
241
242int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp);
243void cgroup_migrate_finish(struct cgroup_mgctx *mgctx);
244void cgroup_migrate_add_src(struct css_set *src_cset, struct cgroup *dst_cgrp,
245 struct cgroup_mgctx *mgctx);
246int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx);
247int cgroup_migrate(struct task_struct *leader, bool threadgroup,
248 struct cgroup_mgctx *mgctx);
249
250int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader,
251 bool threadgroup);
252void cgroup_attach_lock(enum cgroup_attach_lock_mode lock_mode,
253 struct task_struct *tsk);
254void cgroup_attach_unlock(enum cgroup_attach_lock_mode lock_mode,
255 struct task_struct *tsk);
256struct task_struct *cgroup_procs_write_start(char *buf, bool threadgroup,
257 enum cgroup_attach_lock_mode *lock_mode)
258 __acquires(&cgroup_threadgroup_rwsem);
259void cgroup_procs_write_finish(struct task_struct *task,
260 enum cgroup_attach_lock_mode lock_mode)
261 __releases(&cgroup_threadgroup_rwsem);
262
263void cgroup_lock_and_drain_offline(struct cgroup *cgrp);
264
265int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode);
266int cgroup_rmdir(struct kernfs_node *kn);
267int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node,
268 struct kernfs_root *kf_root);
269
270int __cgroup_task_count(const struct cgroup *cgrp);
271int cgroup_task_count(const struct cgroup *cgrp);
272
273/*
274 * rstat.c
275 */
276int css_rstat_init(struct cgroup_subsys_state *css);
277void css_rstat_exit(struct cgroup_subsys_state *css);
278int ss_rstat_init(struct cgroup_subsys *ss);
279void cgroup_base_stat_cputime_show(struct seq_file *seq);
280
281/*
282 * namespace.c
283 */
284extern const struct proc_ns_operations cgroupns_operations;
285
286/*
287 * cgroup-v1.c
288 */
289extern struct cftype cgroup1_base_files[];
290extern struct kernfs_syscall_ops cgroup1_kf_syscall_ops;
291extern const struct fs_parameter_spec cgroup1_fs_parameters[];
292
293int proc_cgroupstats_show(struct seq_file *m, void *v);
294bool cgroup1_ssid_disabled(int ssid);
295void cgroup1_pidlist_destroy_all(struct cgroup *cgrp);
296void cgroup1_release_agent(struct work_struct *work);
297void cgroup1_check_for_release(struct cgroup *cgrp);
298int cgroup1_parse_param(struct fs_context *fc, struct fs_parameter *param);
299int cgroup1_get_tree(struct fs_context *fc);
300int cgroup1_reconfigure(struct fs_context *ctx);
301
302#endif /* __CGROUP_INTERNAL_H */
303