1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_CGROUP_H
3 #define _LINUX_CGROUP_H
4 /*
5 * cgroup interface
6 *
7 * Copyright (C) 2003 BULL SA
8 * Copyright (C) 2004-2006 Silicon Graphics, Inc.
9 *
10 */
11
12 #include <linux/sched.h>
13 #include <linux/nodemask.h>
14 #include <linux/rculist.h>
15 #include <linux/cgroupstats.h>
16 #include <linux/fs.h>
17 #include <linux/seq_file.h>
18 #include <linux/kernfs.h>
19 #include <linux/jump_label.h>
20 #include <linux/types.h>
21 #include <linux/ns_common.h>
22 #include <linux/nsproxy.h>
23 #include <linux/user_namespace.h>
24 #include <linux/refcount.h>
25 #include <linux/kernel_stat.h>
26
27 #include <linux/cgroup-defs.h>
28
29 struct kernel_clone_args;
30
31 #ifdef CONFIG_CGROUPS
32
33 /*
34 * All weight knobs on the default hierarchy should use the following min,
35 * default and max values. The default value is the logarithmic center of
36 * MIN and MAX and allows 100x to be expressed in both directions.
37 */
38 #define CGROUP_WEIGHT_MIN 1
39 #define CGROUP_WEIGHT_DFL 100
40 #define CGROUP_WEIGHT_MAX 10000
41
42 enum {
43 CSS_TASK_ITER_PROCS = (1U << 0), /* walk only threadgroup leaders */
44 CSS_TASK_ITER_THREADED = (1U << 1), /* walk all threaded css_sets in the domain */
45 CSS_TASK_ITER_SKIPPED = (1U << 16), /* internal flags */
46 };
47
48 /* a css_task_iter should be treated as an opaque object */
49 struct css_task_iter {
50 struct cgroup_subsys *ss;
51 unsigned int flags;
52
53 struct list_head *cset_pos;
54 struct list_head *cset_head;
55
56 struct list_head *tcset_pos;
57 struct list_head *tcset_head;
58
59 struct list_head *task_pos;
60
61 struct list_head *cur_tasks_head;
62 struct css_set *cur_cset;
63 struct css_set *cur_dcset;
64 struct task_struct *cur_task;
65 struct list_head iters_node; /* css_set->task_iters */
66 };
67
68 extern struct file_system_type cgroup_fs_type;
69 extern struct cgroup_root cgrp_dfl_root;
70 extern struct css_set init_css_set;
71 extern spinlock_t css_set_lock;
72
73 #define SUBSYS(_x) extern struct cgroup_subsys _x ## _cgrp_subsys;
74 #include <linux/cgroup_subsys.h>
75 #undef SUBSYS
76
77 #define SUBSYS(_x) \
78 extern struct static_key_true _x ## _cgrp_subsys_enabled_key; \
79 extern struct static_key_true _x ## _cgrp_subsys_on_dfl_key;
80 #include <linux/cgroup_subsys.h>
81 #undef SUBSYS
82
83 /**
84 * cgroup_subsys_enabled - fast test on whether a subsys is enabled
85 * @ss: subsystem in question
86 */
87 #define cgroup_subsys_enabled(ss) \
88 static_branch_likely(&ss ## _enabled_key)
89
90 /**
91 * cgroup_subsys_on_dfl - fast test on whether a subsys is on default hierarchy
92 * @ss: subsystem in question
93 */
94 #define cgroup_subsys_on_dfl(ss) \
95 static_branch_likely(&ss ## _on_dfl_key)
96
97 bool css_has_online_children(struct cgroup_subsys_state *css);
98 struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss);
99 struct cgroup_subsys_state *cgroup_e_css(struct cgroup *cgroup,
100 struct cgroup_subsys *ss);
101 struct cgroup_subsys_state *cgroup_get_e_css(struct cgroup *cgroup,
102 struct cgroup_subsys *ss);
103 struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry,
104 struct cgroup_subsys *ss);
105
106 struct cgroup *cgroup_get_from_path(const char *path);
107 struct cgroup *cgroup_get_from_fd(int fd);
108 struct cgroup *cgroup_v1v2_get_from_fd(int fd);
109
110 int cgroup_attach_task_all(struct task_struct *from, struct task_struct *);
111 int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from);
112
113 int cgroup_add_dfl_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
114 int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
115 int cgroup_rm_cftypes(struct cftype *cfts);
116 void cgroup_file_notify(struct cgroup_file *cfile);
117 void cgroup_file_show(struct cgroup_file *cfile, bool show);
118
119 int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry);
120 int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
121 struct pid *pid, struct task_struct *tsk);
122
123 void cgroup_fork(struct task_struct *p);
124 extern int cgroup_can_fork(struct task_struct *p,
125 struct kernel_clone_args *kargs);
126 extern void cgroup_cancel_fork(struct task_struct *p,
127 struct kernel_clone_args *kargs);
128 extern void cgroup_post_fork(struct task_struct *p,
129 struct kernel_clone_args *kargs);
130 void cgroup_exit(struct task_struct *p);
131 void cgroup_release(struct task_struct *p);
132 void cgroup_free(struct task_struct *p);
133
134 int cgroup_init_early(void);
135 int cgroup_init(void);
136
137 int cgroup_parse_float(const char *input, unsigned dec_shift, s64 *v);
138
139 /*
140 * Iteration helpers and macros.
141 */
142
143 struct cgroup_subsys_state *css_next_child(struct cgroup_subsys_state *pos,
144 struct cgroup_subsys_state *parent);
145 struct cgroup_subsys_state *css_next_descendant_pre(struct cgroup_subsys_state *pos,
146 struct cgroup_subsys_state *css);
147 struct cgroup_subsys_state *css_rightmost_descendant(struct cgroup_subsys_state *pos);
148 struct cgroup_subsys_state *css_next_descendant_post(struct cgroup_subsys_state *pos,
149 struct cgroup_subsys_state *css);
150
151 struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset,
152 struct cgroup_subsys_state **dst_cssp);
153 struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset,
154 struct cgroup_subsys_state **dst_cssp);
155
156 void css_task_iter_start(struct cgroup_subsys_state *css, unsigned int flags,
157 struct css_task_iter *it);
158 struct task_struct *css_task_iter_next(struct css_task_iter *it);
159 void css_task_iter_end(struct css_task_iter *it);
160
161 /**
162 * css_for_each_child - iterate through children of a css
163 * @pos: the css * to use as the loop cursor
164 * @parent: css whose children to walk
165 *
166 * Walk @parent's children. Must be called under rcu_read_lock().
167 *
168 * If a subsystem synchronizes ->css_online() and the start of iteration, a
169 * css which finished ->css_online() is guaranteed to be visible in the
170 * future iterations and will stay visible until the last reference is put.
171 * A css which hasn't finished ->css_online() or already finished
172 * ->css_offline() may show up during traversal. It's each subsystem's
173 * responsibility to synchronize against on/offlining.
174 *
175 * It is allowed to temporarily drop RCU read lock during iteration. The
176 * caller is responsible for ensuring that @pos remains accessible until
177 * the start of the next iteration by, for example, bumping the css refcnt.
178 */
179 #define css_for_each_child(pos, parent) \
180 for ((pos) = css_next_child(NULL, (parent)); (pos); \
181 (pos) = css_next_child((pos), (parent)))
182
183 /**
184 * css_for_each_descendant_pre - pre-order walk of a css's descendants
185 * @pos: the css * to use as the loop cursor
186 * @root: css whose descendants to walk
187 *
188 * Walk @root's descendants. @root is included in the iteration and the
189 * first node to be visited. Must be called under rcu_read_lock().
190 *
191 * If a subsystem synchronizes ->css_online() and the start of iteration, a
192 * css which finished ->css_online() is guaranteed to be visible in the
193 * future iterations and will stay visible until the last reference is put.
194 * A css which hasn't finished ->css_online() or already finished
195 * ->css_offline() may show up during traversal. It's each subsystem's
196 * responsibility to synchronize against on/offlining.
197 *
198 * For example, the following guarantees that a descendant can't escape
199 * state updates of its ancestors.
200 *
201 * my_online(@css)
202 * {
203 * Lock @css's parent and @css;
204 * Inherit state from the parent;
205 * Unlock both.
206 * }
207 *
208 * my_update_state(@css)
209 * {
210 * css_for_each_descendant_pre(@pos, @css) {
211 * Lock @pos;
212 * if (@pos == @css)
213 * Update @css's state;
214 * else
215 * Verify @pos is alive and inherit state from its parent;
216 * Unlock @pos;
217 * }
218 * }
219 *
220 * As long as the inheriting step, including checking the parent state, is
221 * enclosed inside @pos locking, double-locking the parent isn't necessary
222 * while inheriting. The state update to the parent is guaranteed to be
223 * visible by walking order and, as long as inheriting operations to the
224 * same @pos are atomic to each other, multiple updates racing each other
225 * still result in the correct state. It's guaranateed that at least one
226 * inheritance happens for any css after the latest update to its parent.
227 *
228 * If checking parent's state requires locking the parent, each inheriting
229 * iteration should lock and unlock both @pos->parent and @pos.
230 *
231 * Alternatively, a subsystem may choose to use a single global lock to
232 * synchronize ->css_online() and ->css_offline() against tree-walking
233 * operations.
234 *
235 * It is allowed to temporarily drop RCU read lock during iteration. The
236 * caller is responsible for ensuring that @pos remains accessible until
237 * the start of the next iteration by, for example, bumping the css refcnt.
238 */
239 #define css_for_each_descendant_pre(pos, css) \
240 for ((pos) = css_next_descendant_pre(NULL, (css)); (pos); \
241 (pos) = css_next_descendant_pre((pos), (css)))
242
243 /**
244 * css_for_each_descendant_post - post-order walk of a css's descendants
245 * @pos: the css * to use as the loop cursor
246 * @css: css whose descendants to walk
247 *
248 * Similar to css_for_each_descendant_pre() but performs post-order
249 * traversal instead. @root is included in the iteration and the last
250 * node to be visited.
251 *
252 * If a subsystem synchronizes ->css_online() and the start of iteration, a
253 * css which finished ->css_online() is guaranteed to be visible in the
254 * future iterations and will stay visible until the last reference is put.
255 * A css which hasn't finished ->css_online() or already finished
256 * ->css_offline() may show up during traversal. It's each subsystem's
257 * responsibility to synchronize against on/offlining.
258 *
259 * Note that the walk visibility guarantee example described in pre-order
260 * walk doesn't apply the same to post-order walks.
261 */
262 #define css_for_each_descendant_post(pos, css) \
263 for ((pos) = css_next_descendant_post(NULL, (css)); (pos); \
264 (pos) = css_next_descendant_post((pos), (css)))
265
266 /**
267 * cgroup_taskset_for_each - iterate cgroup_taskset
268 * @task: the loop cursor
269 * @dst_css: the destination css
270 * @tset: taskset to iterate
271 *
272 * @tset may contain multiple tasks and they may belong to multiple
273 * processes.
274 *
275 * On the v2 hierarchy, there may be tasks from multiple processes and they
276 * may not share the source or destination csses.
277 *
278 * On traditional hierarchies, when there are multiple tasks in @tset, if a
279 * task of a process is in @tset, all tasks of the process are in @tset.
280 * Also, all are guaranteed to share the same source and destination csses.
281 *
282 * Iteration is not in any specific order.
283 */
284 #define cgroup_taskset_for_each(task, dst_css, tset) \
285 for ((task) = cgroup_taskset_first((tset), &(dst_css)); \
286 (task); \
287 (task) = cgroup_taskset_next((tset), &(dst_css)))
288
289 /**
290 * cgroup_taskset_for_each_leader - iterate group leaders in a cgroup_taskset
291 * @leader: the loop cursor
292 * @dst_css: the destination css
293 * @tset: taskset to iterate
294 *
295 * Iterate threadgroup leaders of @tset. For single-task migrations, @tset
296 * may not contain any.
297 */
298 #define cgroup_taskset_for_each_leader(leader, dst_css, tset) \
299 for ((leader) = cgroup_taskset_first((tset), &(dst_css)); \
300 (leader); \
301 (leader) = cgroup_taskset_next((tset), &(dst_css))) \
302 if ((leader) != (leader)->group_leader) \
303 ; \
304 else
305
306 /*
307 * Inline functions.
308 */
309
310 #ifdef CONFIG_DEBUG_CGROUP_REF
311 void css_get(struct cgroup_subsys_state *css);
312 void css_get_many(struct cgroup_subsys_state *css, unsigned int n);
313 bool css_tryget(struct cgroup_subsys_state *css);
314 bool css_tryget_online(struct cgroup_subsys_state *css);
315 void css_put(struct cgroup_subsys_state *css);
316 void css_put_many(struct cgroup_subsys_state *css, unsigned int n);
317 #else
318 #define CGROUP_REF_FN_ATTRS static inline
319 #define CGROUP_REF_EXPORT(fn)
320 #include <linux/cgroup_refcnt.h>
321 #endif
322
323 static inline u64 cgroup_id(const struct cgroup *cgrp)
324 {
325 return cgrp->kn->id;
326 }
327
328 /**
329 * css_is_dying - test whether the specified css is dying
330 * @css: target css
331 *
332 * Test whether @css is in the process of offlining or already offline. In
333 * most cases, ->css_online() and ->css_offline() callbacks should be
334 * enough; however, the actual offline operations are RCU delayed and this
335 * test returns %true also when @css is scheduled to be offlined.
336 *
337 * This is useful, for example, when the use case requires synchronous
338 * behavior with respect to cgroup removal. cgroup removal schedules css
339 * offlining but the css can seem alive while the operation is being
340 * delayed. If the delay affects user visible semantics, this test can be
341 * used to resolve the situation.
342 */
343 static inline bool css_is_dying(struct cgroup_subsys_state *css)
344 {
345 return !(css->flags & CSS_NO_REF) && percpu_ref_is_dying(&css->refcnt);
346 }
347
348 static inline void cgroup_get(struct cgroup *cgrp)
349 {
350 css_get(&cgrp->self);
351 }
352
353 static inline bool cgroup_tryget(struct cgroup *cgrp)
354 {
355 return css_tryget(&cgrp->self);
356 }
357
358 static inline void cgroup_put(struct cgroup *cgrp)
359 {
360 css_put(&cgrp->self);
361 }
362
363 extern struct mutex cgroup_mutex;
364
365 static inline void cgroup_lock(void)
366 {
367 mutex_lock(&cgroup_mutex);
368 }
369
370 static inline void cgroup_unlock(void)
371 {
372 mutex_unlock(&cgroup_mutex);
373 }
374
375 /**
376 * task_css_set_check - obtain a task's css_set with extra access conditions
377 * @task: the task to obtain css_set for
378 * @__c: extra condition expression to be passed to rcu_dereference_check()
379 *
380 * A task's css_set is RCU protected, initialized and exited while holding
381 * task_lock(), and can only be modified while holding both cgroup_mutex
382 * and task_lock() while the task is alive. This macro verifies that the
383 * caller is inside proper critical section and returns @task's css_set.
384 *
385 * The caller can also specify additional allowed conditions via @__c, such
386 * as locks used during the cgroup_subsys::attach() methods.
387 */
388 #ifdef CONFIG_PROVE_RCU
389 #define task_css_set_check(task, __c) \
390 rcu_dereference_check((task)->cgroups, \
391 rcu_read_lock_sched_held() || \
392 lockdep_is_held(&cgroup_mutex) || \
393 lockdep_is_held(&css_set_lock) || \
394 ((task)->flags & PF_EXITING) || (__c))
395 #else
396 #define task_css_set_check(task, __c) \
397 rcu_dereference((task)->cgroups)
398 #endif
399
400 /**
401 * task_css_check - obtain css for (task, subsys) w/ extra access conds
402 * @task: the target task
403 * @subsys_id: the target subsystem ID
404 * @__c: extra condition expression to be passed to rcu_dereference_check()
405 *
406 * Return the cgroup_subsys_state for the (@task, @subsys_id) pair. The
407 * synchronization rules are the same as task_css_set_check().
408 */
409 #define task_css_check(task, subsys_id, __c) \
410 task_css_set_check((task), (__c))->subsys[(subsys_id)]
411
412 /**
413 * task_css_set - obtain a task's css_set
414 * @task: the task to obtain css_set for
415 *
416 * See task_css_set_check().
417 */
418 static inline struct css_set *task_css_set(struct task_struct *task)
419 {
420 return task_css_set_check(task, false);
421 }
422
423 /**
424 * task_css - obtain css for (task, subsys)
425 * @task: the target task
426 * @subsys_id: the target subsystem ID
427 *
428 * See task_css_check().
429 */
430 static inline struct cgroup_subsys_state *task_css(struct task_struct *task,
431 int subsys_id)
432 {
433 return task_css_check(task, subsys_id, false);
434 }
435
436 /**
437 * task_get_css - find and get the css for (task, subsys)
438 * @task: the target task
439 * @subsys_id: the target subsystem ID
440 *
441 * Find the css for the (@task, @subsys_id) combination, increment a
442 * reference on and return it. This function is guaranteed to return a
443 * valid css. The returned css may already have been offlined.
444 */
445 static inline struct cgroup_subsys_state *
446 task_get_css(struct task_struct *task, int subsys_id)
447 {
448 struct cgroup_subsys_state *css;
449
450 rcu_read_lock();
451 while (true) {
452 css = task_css(task, subsys_id);
453 /*
454 * Can't use css_tryget_online() here. A task which has
455 * PF_EXITING set may stay associated with an offline css.
456 * If such task calls this function, css_tryget_online()
457 * will keep failing.
458 */
459 if (likely(css_tryget(css)))
460 break;
461 cpu_relax();
462 }
463 rcu_read_unlock();
464 return css;
465 }
466
467 /**
468 * task_css_is_root - test whether a task belongs to the root css
469 * @task: the target task
470 * @subsys_id: the target subsystem ID
471 *
472 * Test whether @task belongs to the root css on the specified subsystem.
473 * May be invoked in any context.
474 */
475 static inline bool task_css_is_root(struct task_struct *task, int subsys_id)
476 {
477 return task_css_check(task, subsys_id, true) ==
478 init_css_set.subsys[subsys_id];
479 }
480
481 static inline struct cgroup *task_cgroup(struct task_struct *task,
482 int subsys_id)
483 {
484 return task_css(task, subsys_id)->cgroup;
485 }
486
487 static inline struct cgroup *task_dfl_cgroup(struct task_struct *task)
488 {
489 return task_css_set(task)->dfl_cgrp;
490 }
491
492 static inline struct cgroup *cgroup_parent(struct cgroup *cgrp)
493 {
494 struct cgroup_subsys_state *parent_css = cgrp->self.parent;
495
496 if (parent_css)
497 return container_of(parent_css, struct cgroup, self);
498 return NULL;
499 }
500
501 /**
502 * cgroup_is_descendant - test ancestry
503 * @cgrp: the cgroup to be tested
504 * @ancestor: possible ancestor of @cgrp
505 *
506 * Test whether @cgrp is a descendant of @ancestor. It also returns %true
507 * if @cgrp == @ancestor. This function is safe to call as long as @cgrp
508 * and @ancestor are accessible.
509 */
510 static inline bool cgroup_is_descendant(struct cgroup *cgrp,
511 struct cgroup *ancestor)
512 {
513 if (cgrp->root != ancestor->root || cgrp->level < ancestor->level)
514 return false;
515 return cgrp->ancestors[ancestor->level] == ancestor;
516 }
517
518 /**
519 * cgroup_ancestor - find ancestor of cgroup
520 * @cgrp: cgroup to find ancestor of
521 * @ancestor_level: level of ancestor to find starting from root
522 *
523 * Find ancestor of cgroup at specified level starting from root if it exists
524 * and return pointer to it. Return NULL if @cgrp doesn't have ancestor at
525 * @ancestor_level.
526 *
527 * This function is safe to call as long as @cgrp is accessible.
528 */
529 static inline struct cgroup *cgroup_ancestor(struct cgroup *cgrp,
530 int ancestor_level)
531 {
532 if (ancestor_level < 0 || ancestor_level > cgrp->level)
533 return NULL;
534 return cgrp->ancestors[ancestor_level];
535 }
536
537 /**
538 * task_under_cgroup_hierarchy - test task's membership of cgroup ancestry
539 * @task: the task to be tested
540 * @ancestor: possible ancestor of @task's cgroup
541 *
542 * Tests whether @task's default cgroup hierarchy is a descendant of @ancestor.
543 * It follows all the same rules as cgroup_is_descendant, and only applies
544 * to the default hierarchy.
545 */
546 static inline bool task_under_cgroup_hierarchy(struct task_struct *task,
547 struct cgroup *ancestor)
548 {
549 struct css_set *cset = task_css_set(task);
550
551 return cgroup_is_descendant(cset->dfl_cgrp, ancestor);
552 }
553
554 /* no synchronization, the result can only be used as a hint */
555 static inline bool cgroup_is_populated(struct cgroup *cgrp)
556 {
557 return cgrp->nr_populated_csets + cgrp->nr_populated_domain_children +
558 cgrp->nr_populated_threaded_children;
559 }
560
561 /* returns ino associated with a cgroup */
562 static inline ino_t cgroup_ino(struct cgroup *cgrp)
563 {
564 return kernfs_ino(cgrp->kn);
565 }
566
567 /* cft/css accessors for cftype->write() operation */
568 static inline struct cftype *of_cft(struct kernfs_open_file *of)
569 {
570 return of->kn->priv;
571 }
572
573 struct cgroup_subsys_state *of_css(struct kernfs_open_file *of);
574
575 /* cft/css accessors for cftype->seq_*() operations */
576 static inline struct cftype *seq_cft(struct seq_file *seq)
577 {
578 return of_cft(seq->private);
579 }
580
581 static inline struct cgroup_subsys_state *seq_css(struct seq_file *seq)
582 {
583 return of_css(seq->private);
584 }
585
586 /*
587 * Name / path handling functions. All are thin wrappers around the kernfs
588 * counterparts and can be called under any context.
589 */
590
591 static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen)
592 {
593 return kernfs_name(cgrp->kn, buf, buflen);
594 }
595
596 static inline int cgroup_path(struct cgroup *cgrp, char *buf, size_t buflen)
597 {
598 return kernfs_path(cgrp->kn, buf, buflen);
599 }
600
601 static inline void pr_cont_cgroup_name(struct cgroup *cgrp)
602 {
603 pr_cont_kernfs_name(cgrp->kn);
604 }
605
606 static inline void pr_cont_cgroup_path(struct cgroup *cgrp)
607 {
608 pr_cont_kernfs_path(cgrp->kn);
609 }
610
611 bool cgroup_psi_enabled(void);
612
613 static inline void cgroup_init_kthreadd(void)
614 {
615 /*
616 * kthreadd is inherited by all kthreads, keep it in the root so
617 * that the new kthreads are guaranteed to stay in the root until
618 * initialization is finished.
619 */
620 current->no_cgroup_migration = 1;
621 }
622
623 static inline void cgroup_kthread_ready(void)
624 {
625 /*
626 * This kthread finished initialization. The creator should have
627 * set PF_NO_SETAFFINITY if this kthread should stay in the root.
628 */
629 current->no_cgroup_migration = 0;
630 }
631
632 void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen);
633 struct cgroup *cgroup_get_from_id(u64 id);
634 #else /* !CONFIG_CGROUPS */
635
636 struct cgroup_subsys_state;
637 struct cgroup;
638
639 static inline u64 cgroup_id(const struct cgroup *cgrp) { return 1; }
640 static inline void css_get(struct cgroup_subsys_state *css) {}
641 static inline void css_put(struct cgroup_subsys_state *css) {}
642 static inline void cgroup_lock(void) {}
643 static inline void cgroup_unlock(void) {}
644 static inline int cgroup_attach_task_all(struct task_struct *from,
645 struct task_struct *t) { return 0; }
646 static inline int cgroupstats_build(struct cgroupstats *stats,
647 struct dentry *dentry) { return -EINVAL; }
648
649 static inline void cgroup_fork(struct task_struct *p) {}
650 static inline int cgroup_can_fork(struct task_struct *p,
651 struct kernel_clone_args *kargs) { return 0; }
652 static inline void cgroup_cancel_fork(struct task_struct *p,
653 struct kernel_clone_args *kargs) {}
654 static inline void cgroup_post_fork(struct task_struct *p,
655 struct kernel_clone_args *kargs) {}
656 static inline void cgroup_exit(struct task_struct *p) {}
657 static inline void cgroup_release(struct task_struct *p) {}
658 static inline void cgroup_free(struct task_struct *p) {}
659
660 static inline int cgroup_init_early(void) { return 0; }
661 static inline int cgroup_init(void) { return 0; }
662 static inline void cgroup_init_kthreadd(void) {}
663 static inline void cgroup_kthread_ready(void) {}
664
665 static inline struct cgroup *cgroup_parent(struct cgroup *cgrp)
666 {
667 return NULL;
668 }
669
670 static inline bool cgroup_psi_enabled(void)
671 {
672 return false;
673 }
674
675 static inline bool task_under_cgroup_hierarchy(struct task_struct *task,
676 struct cgroup *ancestor)
677 {
678 return true;
679 }
680
681 static inline void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen)
682 {}
683 #endif /* !CONFIG_CGROUPS */
684
685 #ifdef CONFIG_CGROUPS
686 /*
687 * cgroup scalable recursive statistics.
688 */
689 void cgroup_rstat_updated(struct cgroup *cgrp, int cpu);
690 void cgroup_rstat_flush(struct cgroup *cgrp);
691 void cgroup_rstat_flush_hold(struct cgroup *cgrp);
692 void cgroup_rstat_flush_release(struct cgroup *cgrp);
693
694 /*
695 * Basic resource stats.
696 */
697 #ifdef CONFIG_CGROUP_CPUACCT
698 void cpuacct_charge(struct task_struct *tsk, u64 cputime);
699 void cpuacct_account_field(struct task_struct *tsk, int index, u64 val);
700 #else
701 static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
702 static inline void cpuacct_account_field(struct task_struct *tsk, int index,
703 u64 val) {}
704 #endif
705
706 void __cgroup_account_cputime(struct cgroup *cgrp, u64 delta_exec);
707 void __cgroup_account_cputime_field(struct cgroup *cgrp,
708 enum cpu_usage_stat index, u64 delta_exec);
709
710 static inline void cgroup_account_cputime(struct task_struct *task,
711 u64 delta_exec)
712 {
713 struct cgroup *cgrp;
714
715 cpuacct_charge(task, delta_exec);
716
717 cgrp = task_dfl_cgroup(task);
718 if (cgroup_parent(cgrp))
719 __cgroup_account_cputime(cgrp, delta_exec);
720 }
721
722 static inline void cgroup_account_cputime_field(struct task_struct *task,
723 enum cpu_usage_stat index,
724 u64 delta_exec)
725 {
726 struct cgroup *cgrp;
727
728 cpuacct_account_field(task, index, delta_exec);
729
730 cgrp = task_dfl_cgroup(task);
731 if (cgroup_parent(cgrp))
732 __cgroup_account_cputime_field(cgrp, index, delta_exec);
733 }
734
735 #else /* CONFIG_CGROUPS */
736
737 static inline void cgroup_account_cputime(struct task_struct *task,
738 u64 delta_exec) {}
739 static inline void cgroup_account_cputime_field(struct task_struct *task,
740 enum cpu_usage_stat index,
741 u64 delta_exec) {}
742
743 #endif /* CONFIG_CGROUPS */
744
745 /*
746 * sock->sk_cgrp_data handling. For more info, see sock_cgroup_data
747 * definition in cgroup-defs.h.
748 */
749 #ifdef CONFIG_SOCK_CGROUP_DATA
750
751 void cgroup_sk_alloc(struct sock_cgroup_data *skcd);
752 void cgroup_sk_clone(struct sock_cgroup_data *skcd);
753 void cgroup_sk_free(struct sock_cgroup_data *skcd);
754
755 static inline struct cgroup *sock_cgroup_ptr(struct sock_cgroup_data *skcd)
756 {
757 return skcd->cgroup;
758 }
759
760 #else /* CONFIG_CGROUP_DATA */
761
762 static inline void cgroup_sk_alloc(struct sock_cgroup_data *skcd) {}
763 static inline void cgroup_sk_clone(struct sock_cgroup_data *skcd) {}
764 static inline void cgroup_sk_free(struct sock_cgroup_data *skcd) {}
765
766 #endif /* CONFIG_CGROUP_DATA */
767
768 struct cgroup_namespace {
769 struct ns_common ns;
770 struct user_namespace *user_ns;
771 struct ucounts *ucounts;
772 struct css_set *root_cset;
773 };
774
775 extern struct cgroup_namespace init_cgroup_ns;
776
777 #ifdef CONFIG_CGROUPS
778
779 void free_cgroup_ns(struct cgroup_namespace *ns);
780
781 struct cgroup_namespace *copy_cgroup_ns(unsigned long flags,
782 struct user_namespace *user_ns,
783 struct cgroup_namespace *old_ns);
784
785 int cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
786 struct cgroup_namespace *ns);
787
788 #else /* !CONFIG_CGROUPS */
789
790 static inline void free_cgroup_ns(struct cgroup_namespace *ns) { }
791 static inline struct cgroup_namespace *
792 copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
793 struct cgroup_namespace *old_ns)
794 {
795 return old_ns;
796 }
797
798 #endif /* !CONFIG_CGROUPS */
799
800 static inline void get_cgroup_ns(struct cgroup_namespace *ns)
801 {
802 if (ns)
803 refcount_inc(&ns->ns.count);
804 }
805
806 static inline void put_cgroup_ns(struct cgroup_namespace *ns)
807 {
808 if (ns && refcount_dec_and_test(&ns->ns.count))
809 free_cgroup_ns(ns);
810 }
811
812 #ifdef CONFIG_CGROUPS
813
814 void cgroup_enter_frozen(void);
815 void cgroup_leave_frozen(bool always_leave);
816 void cgroup_update_frozen(struct cgroup *cgrp);
817 void cgroup_freeze(struct cgroup *cgrp, bool freeze);
818 void cgroup_freezer_migrate_task(struct task_struct *task, struct cgroup *src,
819 struct cgroup *dst);
820
821 static inline bool cgroup_task_frozen(struct task_struct *task)
822 {
823 return task->frozen;
824 }
825
826 #else /* !CONFIG_CGROUPS */
827
828 static inline void cgroup_enter_frozen(void) { }
829 static inline void cgroup_leave_frozen(bool always_leave) { }
830 static inline bool cgroup_task_frozen(struct task_struct *task)
831 {
832 return false;
833 }
834
835 #endif /* !CONFIG_CGROUPS */
836
837 #ifdef CONFIG_CGROUP_BPF
838 static inline void cgroup_bpf_get(struct cgroup *cgrp)
839 {
840 percpu_ref_get(&cgrp->bpf.refcnt);
841 }
842
843 static inline void cgroup_bpf_put(struct cgroup *cgrp)
844 {
845 percpu_ref_put(&cgrp->bpf.refcnt);
846 }
847
848 #else /* CONFIG_CGROUP_BPF */
849
850 static inline void cgroup_bpf_get(struct cgroup *cgrp) {}
851 static inline void cgroup_bpf_put(struct cgroup *cgrp) {}
852
853 #endif /* CONFIG_CGROUP_BPF */
854
855 struct cgroup *task_get_cgroup1(struct task_struct *tsk, int hierarchy_id);
856
857 #endif /* _LINUX_CGROUP_H */
858
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