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/cpumask.h>
14 #include <linux/nodemask.h>
15 #include <linux/rculist.h>
16 #include <linux/cgroupstats.h>
17 #include <linux/fs.h>
18 #include <linux/seq_file.h>
19 #include <linux/kernfs.h>
20 #include <linux/jump_label.h>
21 #include <linux/types.h>
22 #include <linux/ns_common.h>
23 #include <linux/nsproxy.h>
24 #include <linux/user_namespace.h>
25 #include <linux/refcount.h>
26 #include <linux/kernel_stat.h>
27 
28 #include <linux/cgroup-defs.h>
29 
30 struct kernel_clone_args;
31 
32 #ifdef CONFIG_CGROUPS
33 
34 /*
35  * All weight knobs on the default hierarchy should use the following min,
36  * default and max values.  The default value is the logarithmic center of
37  * MIN and MAX and allows 100x to be expressed in both directions.
38  */
39 #define CGROUP_WEIGHT_MIN		1
40 #define CGROUP_WEIGHT_DFL		100
41 #define CGROUP_WEIGHT_MAX		10000
42 
43 /* walk only threadgroup leaders */
44 #define CSS_TASK_ITER_PROCS		(1U << 0)
45 /* walk all threaded css_sets in the domain */
46 #define CSS_TASK_ITER_THREADED		(1U << 1)
47 
48 /* internal flags */
49 #define CSS_TASK_ITER_SKIPPED		(1U << 16)
50 
51 /* a css_task_iter should be treated as an opaque object */
52 struct css_task_iter {
53 	struct cgroup_subsys		*ss;
54 	unsigned int			flags;
55 
56 	struct list_head		*cset_pos;
57 	struct list_head		*cset_head;
58 
59 	struct list_head		*tcset_pos;
60 	struct list_head		*tcset_head;
61 
62 	struct list_head		*task_pos;
63 
64 	struct list_head		*cur_tasks_head;
65 	struct css_set			*cur_cset;
66 	struct css_set			*cur_dcset;
67 	struct task_struct		*cur_task;
68 	struct list_head		iters_node;	/* css_set->task_iters */
69 };
70 
71 extern struct file_system_type cgroup_fs_type;
72 extern struct cgroup_root cgrp_dfl_root;
73 extern struct css_set init_css_set;
74 
75 #define SUBSYS(_x) extern struct cgroup_subsys _x ## _cgrp_subsys;
76 #include <linux/cgroup_subsys.h>
77 #undef SUBSYS
78 
79 #define SUBSYS(_x)								\
80 	extern struct static_key_true _x ## _cgrp_subsys_enabled_key;		\
81 	extern struct static_key_true _x ## _cgrp_subsys_on_dfl_key;
82 #include <linux/cgroup_subsys.h>
83 #undef SUBSYS
84 
85 /**
86  * cgroup_subsys_enabled - fast test on whether a subsys is enabled
87  * @ss: subsystem in question
88  */
89 #define cgroup_subsys_enabled(ss)						\
90 	static_branch_likely(&ss ## _enabled_key)
91 
92 /**
93  * cgroup_subsys_on_dfl - fast test on whether a subsys is on default hierarchy
94  * @ss: subsystem in question
95  */
96 #define cgroup_subsys_on_dfl(ss)						\
97 	static_branch_likely(&ss ## _on_dfl_key)
98 
99 bool css_has_online_children(struct cgroup_subsys_state *css);
100 struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss);
101 struct cgroup_subsys_state *cgroup_e_css(struct cgroup *cgroup,
102 					 struct cgroup_subsys *ss);
103 struct cgroup_subsys_state *cgroup_get_e_css(struct cgroup *cgroup,
104 					     struct cgroup_subsys *ss);
105 struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry,
106 						       struct cgroup_subsys *ss);
107 
108 struct cgroup *cgroup_get_from_path(const char *path);
109 struct cgroup *cgroup_get_from_fd(int fd);
110 struct cgroup *cgroup_v1v2_get_from_fd(int fd);
111 
112 int cgroup_attach_task_all(struct task_struct *from, struct task_struct *);
113 int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from);
114 
115 int cgroup_add_dfl_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
116 int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
117 int cgroup_rm_cftypes(struct cftype *cfts);
118 void cgroup_file_notify(struct cgroup_file *cfile);
119 void cgroup_file_show(struct cgroup_file *cfile, bool show);
120 
121 int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry);
122 int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
123 		     struct pid *pid, struct task_struct *tsk);
124 
125 void cgroup_fork(struct task_struct *p);
126 extern int cgroup_can_fork(struct task_struct *p,
127 			   struct kernel_clone_args *kargs);
128 extern void cgroup_cancel_fork(struct task_struct *p,
129 			       struct kernel_clone_args *kargs);
130 extern void cgroup_post_fork(struct task_struct *p,
131 			     struct kernel_clone_args *kargs);
132 void cgroup_exit(struct task_struct *p);
133 void cgroup_release(struct task_struct *p);
134 void cgroup_free(struct task_struct *p);
135 
136 int cgroup_init_early(void);
137 int cgroup_init(void);
138 
139 int cgroup_parse_float(const char *input, unsigned dec_shift, s64 *v);
140 
141 /*
142  * Iteration helpers and macros.
143  */
144 
145 struct cgroup_subsys_state *css_next_child(struct cgroup_subsys_state *pos,
146 					   struct cgroup_subsys_state *parent);
147 struct cgroup_subsys_state *css_next_descendant_pre(struct cgroup_subsys_state *pos,
148 						    struct cgroup_subsys_state *css);
149 struct cgroup_subsys_state *css_rightmost_descendant(struct cgroup_subsys_state *pos);
150 struct cgroup_subsys_state *css_next_descendant_post(struct cgroup_subsys_state *pos,
151 						     struct cgroup_subsys_state *css);
152 
153 struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset,
154 					 struct cgroup_subsys_state **dst_cssp);
155 struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset,
156 					struct cgroup_subsys_state **dst_cssp);
157 
158 void css_task_iter_start(struct cgroup_subsys_state *css, unsigned int flags,
159 			 struct css_task_iter *it);
160 struct task_struct *css_task_iter_next(struct css_task_iter *it);
161 void css_task_iter_end(struct css_task_iter *it);
162 
163 /**
164  * css_for_each_child - iterate through children of a css
165  * @pos: the css * to use as the loop cursor
166  * @parent: css whose children to walk
167  *
168  * Walk @parent's children.  Must be called under rcu_read_lock().
169  *
170  * If a subsystem synchronizes ->css_online() and the start of iteration, a
171  * css which finished ->css_online() is guaranteed to be visible in the
172  * future iterations and will stay visible until the last reference is put.
173  * A css which hasn't finished ->css_online() or already finished
174  * ->css_offline() may show up during traversal.  It's each subsystem's
175  * responsibility to synchronize against on/offlining.
176  *
177  * It is allowed to temporarily drop RCU read lock during iteration.  The
178  * caller is responsible for ensuring that @pos remains accessible until
179  * the start of the next iteration by, for example, bumping the css refcnt.
180  */
181 #define css_for_each_child(pos, parent)					\
182 	for ((pos) = css_next_child(NULL, (parent)); (pos);		\
183 	     (pos) = css_next_child((pos), (parent)))
184 
185 /**
186  * css_for_each_descendant_pre - pre-order walk of a css's descendants
187  * @pos: the css * to use as the loop cursor
188  * @root: css whose descendants to walk
189  *
190  * Walk @root's descendants.  @root is included in the iteration and the
191  * first node to be visited.  Must be called under rcu_read_lock().
192  *
193  * If a subsystem synchronizes ->css_online() and the start of iteration, a
194  * css which finished ->css_online() is guaranteed to be visible in the
195  * future iterations and will stay visible until the last reference is put.
196  * A css which hasn't finished ->css_online() or already finished
197  * ->css_offline() may show up during traversal.  It's each subsystem's
198  * responsibility to synchronize against on/offlining.
199  *
200  * For example, the following guarantees that a descendant can't escape
201  * state updates of its ancestors.
202  *
203  * my_online(@css)
204  * {
205  *	Lock @css's parent and @css;
206  *	Inherit state from the parent;
207  *	Unlock both.
208  * }
209  *
210  * my_update_state(@css)
211  * {
212  *	css_for_each_descendant_pre(@pos, @css) {
213  *		Lock @pos;
214  *		if (@pos == @css)
215  *			Update @css's state;
216  *		else
217  *			Verify @pos is alive and inherit state from its parent;
218  *		Unlock @pos;
219  *	}
220  * }
221  *
222  * As long as the inheriting step, including checking the parent state, is
223  * enclosed inside @pos locking, double-locking the parent isn't necessary
224  * while inheriting.  The state update to the parent is guaranteed to be
225  * visible by walking order and, as long as inheriting operations to the
226  * same @pos are atomic to each other, multiple updates racing each other
227  * still result in the correct state.  It's guaranateed that at least one
228  * inheritance happens for any css after the latest update to its parent.
229  *
230  * If checking parent's state requires locking the parent, each inheriting
231  * iteration should lock and unlock both @pos->parent and @pos.
232  *
233  * Alternatively, a subsystem may choose to use a single global lock to
234  * synchronize ->css_online() and ->css_offline() against tree-walking
235  * operations.
236  *
237  * It is allowed to temporarily drop RCU read lock during iteration.  The
238  * caller is responsible for ensuring that @pos remains accessible until
239  * the start of the next iteration by, for example, bumping the css refcnt.
240  */
241 #define css_for_each_descendant_pre(pos, css)				\
242 	for ((pos) = css_next_descendant_pre(NULL, (css)); (pos);	\
243 	     (pos) = css_next_descendant_pre((pos), (css)))
244 
245 /**
246  * css_for_each_descendant_post - post-order walk of a css's descendants
247  * @pos: the css * to use as the loop cursor
248  * @css: css whose descendants to walk
249  *
250  * Similar to css_for_each_descendant_pre() but performs post-order
251  * traversal instead.  @root is included in the iteration and the last
252  * node to be visited.
253  *
254  * If a subsystem synchronizes ->css_online() and the start of iteration, a
255  * css which finished ->css_online() is guaranteed to be visible in the
256  * future iterations and will stay visible until the last reference is put.
257  * A css which hasn't finished ->css_online() or already finished
258  * ->css_offline() may show up during traversal.  It's each subsystem's
259  * responsibility to synchronize against on/offlining.
260  *
261  * Note that the walk visibility guarantee example described in pre-order
262  * walk doesn't apply the same to post-order walks.
263  */
264 #define css_for_each_descendant_post(pos, css)				\
265 	for ((pos) = css_next_descendant_post(NULL, (css)); (pos);	\
266 	     (pos) = css_next_descendant_post((pos), (css)))
267 
268 /**
269  * cgroup_taskset_for_each - iterate cgroup_taskset
270  * @task: the loop cursor
271  * @dst_css: the destination css
272  * @tset: taskset to iterate
273  *
274  * @tset may contain multiple tasks and they may belong to multiple
275  * processes.
276  *
277  * On the v2 hierarchy, there may be tasks from multiple processes and they
278  * may not share the source or destination csses.
279  *
280  * On traditional hierarchies, when there are multiple tasks in @tset, if a
281  * task of a process is in @tset, all tasks of the process are in @tset.
282  * Also, all are guaranteed to share the same source and destination csses.
283  *
284  * Iteration is not in any specific order.
285  */
286 #define cgroup_taskset_for_each(task, dst_css, tset)			\
287 	for ((task) = cgroup_taskset_first((tset), &(dst_css));		\
288 	     (task);							\
289 	     (task) = cgroup_taskset_next((tset), &(dst_css)))
290 
291 /**
292  * cgroup_taskset_for_each_leader - iterate group leaders in a cgroup_taskset
293  * @leader: the loop cursor
294  * @dst_css: the destination css
295  * @tset: taskset to iterate
296  *
297  * Iterate threadgroup leaders of @tset.  For single-task migrations, @tset
298  * may not contain any.
299  */
300 #define cgroup_taskset_for_each_leader(leader, dst_css, tset)		\
301 	for ((leader) = cgroup_taskset_first((tset), &(dst_css));	\
302 	     (leader);							\
303 	     (leader) = cgroup_taskset_next((tset), &(dst_css)))	\
304 		if ((leader) != (leader)->group_leader)			\
305 			;						\
306 		else
307 
308 /*
309  * Inline functions.
310  */
311 
312 #ifdef CONFIG_DEBUG_CGROUP_REF
313 void css_get(struct cgroup_subsys_state *css);
314 void css_get_many(struct cgroup_subsys_state *css, unsigned int n);
315 bool css_tryget(struct cgroup_subsys_state *css);
316 bool css_tryget_online(struct cgroup_subsys_state *css);
317 void css_put(struct cgroup_subsys_state *css);
318 void css_put_many(struct cgroup_subsys_state *css, unsigned int n);
319 #else
320 #define CGROUP_REF_FN_ATTRS	static inline
321 #define CGROUP_REF_EXPORT(fn)
322 #include <linux/cgroup_refcnt.h>
323 #endif
324 
cgroup_id(const struct cgroup * cgrp)325 static inline u64 cgroup_id(const struct cgroup *cgrp)
326 {
327 	return cgrp->kn->id;
328 }
329 
330 /**
331  * css_is_dying - test whether the specified css is dying
332  * @css: target css
333  *
334  * Test whether @css is in the process of offlining or already offline.  In
335  * most cases, ->css_online() and ->css_offline() callbacks should be
336  * enough; however, the actual offline operations are RCU delayed and this
337  * test returns %true also when @css is scheduled to be offlined.
338  *
339  * This is useful, for example, when the use case requires synchronous
340  * behavior with respect to cgroup removal.  cgroup removal schedules css
341  * offlining but the css can seem alive while the operation is being
342  * delayed.  If the delay affects user visible semantics, this test can be
343  * used to resolve the situation.
344  */
css_is_dying(struct cgroup_subsys_state * css)345 static inline bool css_is_dying(struct cgroup_subsys_state *css)
346 {
347 	return !(css->flags & CSS_NO_REF) && percpu_ref_is_dying(&css->refcnt);
348 }
349 
cgroup_get(struct cgroup * cgrp)350 static inline void cgroup_get(struct cgroup *cgrp)
351 {
352 	css_get(&cgrp->self);
353 }
354 
cgroup_tryget(struct cgroup * cgrp)355 static inline bool cgroup_tryget(struct cgroup *cgrp)
356 {
357 	return css_tryget(&cgrp->self);
358 }
359 
cgroup_put(struct cgroup * cgrp)360 static inline void cgroup_put(struct cgroup *cgrp)
361 {
362 	css_put(&cgrp->self);
363 }
364 
365 extern struct mutex cgroup_mutex;
366 
cgroup_lock(void)367 static inline void cgroup_lock(void)
368 {
369 	mutex_lock(&cgroup_mutex);
370 }
371 
cgroup_unlock(void)372 static inline void cgroup_unlock(void)
373 {
374 	mutex_unlock(&cgroup_mutex);
375 }
376 
377 /**
378  * task_css_set_check - obtain a task's css_set with extra access conditions
379  * @task: the task to obtain css_set for
380  * @__c: extra condition expression to be passed to rcu_dereference_check()
381  *
382  * A task's css_set is RCU protected, initialized and exited while holding
383  * task_lock(), and can only be modified while holding both cgroup_mutex
384  * and task_lock() while the task is alive.  This macro verifies that the
385  * caller is inside proper critical section and returns @task's css_set.
386  *
387  * The caller can also specify additional allowed conditions via @__c, such
388  * as locks used during the cgroup_subsys::attach() methods.
389  */
390 #ifdef CONFIG_PROVE_RCU
391 extern spinlock_t css_set_lock;
392 #define task_css_set_check(task, __c)					\
393 	rcu_dereference_check((task)->cgroups,				\
394 		rcu_read_lock_sched_held() ||				\
395 		lockdep_is_held(&cgroup_mutex) ||			\
396 		lockdep_is_held(&css_set_lock) ||			\
397 		((task)->flags & PF_EXITING) || (__c))
398 #else
399 #define task_css_set_check(task, __c)					\
400 	rcu_dereference((task)->cgroups)
401 #endif
402 
403 /**
404  * task_css_check - obtain css for (task, subsys) w/ extra access conds
405  * @task: the target task
406  * @subsys_id: the target subsystem ID
407  * @__c: extra condition expression to be passed to rcu_dereference_check()
408  *
409  * Return the cgroup_subsys_state for the (@task, @subsys_id) pair.  The
410  * synchronization rules are the same as task_css_set_check().
411  */
412 #define task_css_check(task, subsys_id, __c)				\
413 	task_css_set_check((task), (__c))->subsys[(subsys_id)]
414 
415 /**
416  * task_css_set - obtain a task's css_set
417  * @task: the task to obtain css_set for
418  *
419  * See task_css_set_check().
420  */
task_css_set(struct task_struct * task)421 static inline struct css_set *task_css_set(struct task_struct *task)
422 {
423 	return task_css_set_check(task, false);
424 }
425 
426 /**
427  * task_css - obtain css for (task, subsys)
428  * @task: the target task
429  * @subsys_id: the target subsystem ID
430  *
431  * See task_css_check().
432  */
task_css(struct task_struct * task,int subsys_id)433 static inline struct cgroup_subsys_state *task_css(struct task_struct *task,
434 						   int subsys_id)
435 {
436 	return task_css_check(task, subsys_id, false);
437 }
438 
439 /**
440  * task_get_css - find and get the css for (task, subsys)
441  * @task: the target task
442  * @subsys_id: the target subsystem ID
443  *
444  * Find the css for the (@task, @subsys_id) combination, increment a
445  * reference on and return it.  This function is guaranteed to return a
446  * valid css.  The returned css may already have been offlined.
447  */
448 static inline struct cgroup_subsys_state *
task_get_css(struct task_struct * task,int subsys_id)449 task_get_css(struct task_struct *task, int subsys_id)
450 {
451 	struct cgroup_subsys_state *css;
452 
453 	rcu_read_lock();
454 	while (true) {
455 		css = task_css(task, subsys_id);
456 		/*
457 		 * Can't use css_tryget_online() here.  A task which has
458 		 * PF_EXITING set may stay associated with an offline css.
459 		 * If such task calls this function, css_tryget_online()
460 		 * will keep failing.
461 		 */
462 		if (likely(css_tryget(css)))
463 			break;
464 		cpu_relax();
465 	}
466 	rcu_read_unlock();
467 	return css;
468 }
469 
470 /**
471  * task_css_is_root - test whether a task belongs to the root css
472  * @task: the target task
473  * @subsys_id: the target subsystem ID
474  *
475  * Test whether @task belongs to the root css on the specified subsystem.
476  * May be invoked in any context.
477  */
task_css_is_root(struct task_struct * task,int subsys_id)478 static inline bool task_css_is_root(struct task_struct *task, int subsys_id)
479 {
480 	return task_css_check(task, subsys_id, true) ==
481 		init_css_set.subsys[subsys_id];
482 }
483 
task_cgroup(struct task_struct * task,int subsys_id)484 static inline struct cgroup *task_cgroup(struct task_struct *task,
485 					 int subsys_id)
486 {
487 	return task_css(task, subsys_id)->cgroup;
488 }
489 
task_dfl_cgroup(struct task_struct * task)490 static inline struct cgroup *task_dfl_cgroup(struct task_struct *task)
491 {
492 	return task_css_set(task)->dfl_cgrp;
493 }
494 
cgroup_parent(struct cgroup * cgrp)495 static inline struct cgroup *cgroup_parent(struct cgroup *cgrp)
496 {
497 	struct cgroup_subsys_state *parent_css = cgrp->self.parent;
498 
499 	if (parent_css)
500 		return container_of(parent_css, struct cgroup, self);
501 	return NULL;
502 }
503 
504 /**
505  * cgroup_is_descendant - test ancestry
506  * @cgrp: the cgroup to be tested
507  * @ancestor: possible ancestor of @cgrp
508  *
509  * Test whether @cgrp is a descendant of @ancestor.  It also returns %true
510  * if @cgrp == @ancestor.  This function is safe to call as long as @cgrp
511  * and @ancestor are accessible.
512  */
cgroup_is_descendant(struct cgroup * cgrp,struct cgroup * ancestor)513 static inline bool cgroup_is_descendant(struct cgroup *cgrp,
514 					struct cgroup *ancestor)
515 {
516 	if (cgrp->root != ancestor->root || cgrp->level < ancestor->level)
517 		return false;
518 	return cgrp->ancestors[ancestor->level] == ancestor;
519 }
520 
521 /**
522  * cgroup_ancestor - find ancestor of cgroup
523  * @cgrp: cgroup to find ancestor of
524  * @ancestor_level: level of ancestor to find starting from root
525  *
526  * Find ancestor of cgroup at specified level starting from root if it exists
527  * and return pointer to it. Return NULL if @cgrp doesn't have ancestor at
528  * @ancestor_level.
529  *
530  * This function is safe to call as long as @cgrp is accessible.
531  */
cgroup_ancestor(struct cgroup * cgrp,int ancestor_level)532 static inline struct cgroup *cgroup_ancestor(struct cgroup *cgrp,
533 					     int ancestor_level)
534 {
535 	if (ancestor_level < 0 || ancestor_level > cgrp->level)
536 		return NULL;
537 	return cgrp->ancestors[ancestor_level];
538 }
539 
540 /**
541  * task_under_cgroup_hierarchy - test task's membership of cgroup ancestry
542  * @task: the task to be tested
543  * @ancestor: possible ancestor of @task's cgroup
544  *
545  * Tests whether @task's default cgroup hierarchy is a descendant of @ancestor.
546  * It follows all the same rules as cgroup_is_descendant, and only applies
547  * to the default hierarchy.
548  */
task_under_cgroup_hierarchy(struct task_struct * task,struct cgroup * ancestor)549 static inline bool task_under_cgroup_hierarchy(struct task_struct *task,
550 					       struct cgroup *ancestor)
551 {
552 	struct css_set *cset = task_css_set(task);
553 
554 	return cgroup_is_descendant(cset->dfl_cgrp, ancestor);
555 }
556 
557 /* no synchronization, the result can only be used as a hint */
cgroup_is_populated(struct cgroup * cgrp)558 static inline bool cgroup_is_populated(struct cgroup *cgrp)
559 {
560 	return cgrp->nr_populated_csets + cgrp->nr_populated_domain_children +
561 		cgrp->nr_populated_threaded_children;
562 }
563 
564 /* returns ino associated with a cgroup */
cgroup_ino(struct cgroup * cgrp)565 static inline ino_t cgroup_ino(struct cgroup *cgrp)
566 {
567 	return kernfs_ino(cgrp->kn);
568 }
569 
570 /* cft/css accessors for cftype->write() operation */
of_cft(struct kernfs_open_file * of)571 static inline struct cftype *of_cft(struct kernfs_open_file *of)
572 {
573 	return of->kn->priv;
574 }
575 
576 struct cgroup_subsys_state *of_css(struct kernfs_open_file *of);
577 
578 /* cft/css accessors for cftype->seq_*() operations */
seq_cft(struct seq_file * seq)579 static inline struct cftype *seq_cft(struct seq_file *seq)
580 {
581 	return of_cft(seq->private);
582 }
583 
seq_css(struct seq_file * seq)584 static inline struct cgroup_subsys_state *seq_css(struct seq_file *seq)
585 {
586 	return of_css(seq->private);
587 }
588 
589 /*
590  * Name / path handling functions.  All are thin wrappers around the kernfs
591  * counterparts and can be called under any context.
592  */
593 
cgroup_name(struct cgroup * cgrp,char * buf,size_t buflen)594 static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen)
595 {
596 	return kernfs_name(cgrp->kn, buf, buflen);
597 }
598 
cgroup_path(struct cgroup * cgrp,char * buf,size_t buflen)599 static inline int cgroup_path(struct cgroup *cgrp, char *buf, size_t buflen)
600 {
601 	return kernfs_path(cgrp->kn, buf, buflen);
602 }
603 
pr_cont_cgroup_name(struct cgroup * cgrp)604 static inline void pr_cont_cgroup_name(struct cgroup *cgrp)
605 {
606 	pr_cont_kernfs_name(cgrp->kn);
607 }
608 
pr_cont_cgroup_path(struct cgroup * cgrp)609 static inline void pr_cont_cgroup_path(struct cgroup *cgrp)
610 {
611 	pr_cont_kernfs_path(cgrp->kn);
612 }
613 
614 bool cgroup_psi_enabled(void);
615 
cgroup_init_kthreadd(void)616 static inline void cgroup_init_kthreadd(void)
617 {
618 	/*
619 	 * kthreadd is inherited by all kthreads, keep it in the root so
620 	 * that the new kthreads are guaranteed to stay in the root until
621 	 * initialization is finished.
622 	 */
623 	current->no_cgroup_migration = 1;
624 }
625 
cgroup_kthread_ready(void)626 static inline void cgroup_kthread_ready(void)
627 {
628 	/*
629 	 * This kthread finished initialization.  The creator should have
630 	 * set PF_NO_SETAFFINITY if this kthread should stay in the root.
631 	 */
632 	current->no_cgroup_migration = 0;
633 }
634 
635 void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen);
636 struct cgroup *cgroup_get_from_id(u64 id);
637 #else /* !CONFIG_CGROUPS */
638 
639 struct cgroup_subsys_state;
640 struct cgroup;
641 
cgroup_id(const struct cgroup * cgrp)642 static inline u64 cgroup_id(const struct cgroup *cgrp) { return 1; }
css_get(struct cgroup_subsys_state * css)643 static inline void css_get(struct cgroup_subsys_state *css) {}
css_put(struct cgroup_subsys_state * css)644 static inline void css_put(struct cgroup_subsys_state *css) {}
cgroup_lock(void)645 static inline void cgroup_lock(void) {}
cgroup_unlock(void)646 static inline void cgroup_unlock(void) {}
cgroup_attach_task_all(struct task_struct * from,struct task_struct * t)647 static inline int cgroup_attach_task_all(struct task_struct *from,
648 					 struct task_struct *t) { return 0; }
cgroupstats_build(struct cgroupstats * stats,struct dentry * dentry)649 static inline int cgroupstats_build(struct cgroupstats *stats,
650 				    struct dentry *dentry) { return -EINVAL; }
651 
cgroup_fork(struct task_struct * p)652 static inline void cgroup_fork(struct task_struct *p) {}
cgroup_can_fork(struct task_struct * p,struct kernel_clone_args * kargs)653 static inline int cgroup_can_fork(struct task_struct *p,
654 				  struct kernel_clone_args *kargs) { return 0; }
cgroup_cancel_fork(struct task_struct * p,struct kernel_clone_args * kargs)655 static inline void cgroup_cancel_fork(struct task_struct *p,
656 				      struct kernel_clone_args *kargs) {}
cgroup_post_fork(struct task_struct * p,struct kernel_clone_args * kargs)657 static inline void cgroup_post_fork(struct task_struct *p,
658 				    struct kernel_clone_args *kargs) {}
cgroup_exit(struct task_struct * p)659 static inline void cgroup_exit(struct task_struct *p) {}
cgroup_release(struct task_struct * p)660 static inline void cgroup_release(struct task_struct *p) {}
cgroup_free(struct task_struct * p)661 static inline void cgroup_free(struct task_struct *p) {}
662 
cgroup_init_early(void)663 static inline int cgroup_init_early(void) { return 0; }
cgroup_init(void)664 static inline int cgroup_init(void) { return 0; }
cgroup_init_kthreadd(void)665 static inline void cgroup_init_kthreadd(void) {}
cgroup_kthread_ready(void)666 static inline void cgroup_kthread_ready(void) {}
667 
cgroup_parent(struct cgroup * cgrp)668 static inline struct cgroup *cgroup_parent(struct cgroup *cgrp)
669 {
670 	return NULL;
671 }
672 
cgroup_psi_enabled(void)673 static inline bool cgroup_psi_enabled(void)
674 {
675 	return false;
676 }
677 
task_under_cgroup_hierarchy(struct task_struct * task,struct cgroup * ancestor)678 static inline bool task_under_cgroup_hierarchy(struct task_struct *task,
679 					       struct cgroup *ancestor)
680 {
681 	return true;
682 }
683 
cgroup_path_from_kernfs_id(u64 id,char * buf,size_t buflen)684 static inline void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen)
685 {}
686 #endif /* !CONFIG_CGROUPS */
687 
688 #ifdef CONFIG_CGROUPS
689 /*
690  * cgroup scalable recursive statistics.
691  */
692 void cgroup_rstat_updated(struct cgroup *cgrp, int cpu);
693 void cgroup_rstat_flush(struct cgroup *cgrp);
694 void cgroup_rstat_flush_hold(struct cgroup *cgrp);
695 void cgroup_rstat_flush_release(void);
696 
697 /*
698  * Basic resource stats.
699  */
700 #ifdef CONFIG_CGROUP_CPUACCT
701 void cpuacct_charge(struct task_struct *tsk, u64 cputime);
702 void cpuacct_account_field(struct task_struct *tsk, int index, u64 val);
703 #else
cpuacct_charge(struct task_struct * tsk,u64 cputime)704 static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
cpuacct_account_field(struct task_struct * tsk,int index,u64 val)705 static inline void cpuacct_account_field(struct task_struct *tsk, int index,
706 					 u64 val) {}
707 #endif
708 
709 void __cgroup_account_cputime(struct cgroup *cgrp, u64 delta_exec);
710 void __cgroup_account_cputime_field(struct cgroup *cgrp,
711 				    enum cpu_usage_stat index, u64 delta_exec);
712 
cgroup_account_cputime(struct task_struct * task,u64 delta_exec)713 static inline void cgroup_account_cputime(struct task_struct *task,
714 					  u64 delta_exec)
715 {
716 	struct cgroup *cgrp;
717 
718 	cpuacct_charge(task, delta_exec);
719 
720 	cgrp = task_dfl_cgroup(task);
721 	if (cgroup_parent(cgrp))
722 		__cgroup_account_cputime(cgrp, delta_exec);
723 }
724 
cgroup_account_cputime_field(struct task_struct * task,enum cpu_usage_stat index,u64 delta_exec)725 static inline void cgroup_account_cputime_field(struct task_struct *task,
726 						enum cpu_usage_stat index,
727 						u64 delta_exec)
728 {
729 	struct cgroup *cgrp;
730 
731 	cpuacct_account_field(task, index, delta_exec);
732 
733 	cgrp = task_dfl_cgroup(task);
734 	if (cgroup_parent(cgrp))
735 		__cgroup_account_cputime_field(cgrp, index, delta_exec);
736 }
737 
738 #else	/* CONFIG_CGROUPS */
739 
cgroup_account_cputime(struct task_struct * task,u64 delta_exec)740 static inline void cgroup_account_cputime(struct task_struct *task,
741 					  u64 delta_exec) {}
cgroup_account_cputime_field(struct task_struct * task,enum cpu_usage_stat index,u64 delta_exec)742 static inline void cgroup_account_cputime_field(struct task_struct *task,
743 						enum cpu_usage_stat index,
744 						u64 delta_exec) {}
745 
746 #endif	/* CONFIG_CGROUPS */
747 
748 /*
749  * sock->sk_cgrp_data handling.  For more info, see sock_cgroup_data
750  * definition in cgroup-defs.h.
751  */
752 #ifdef CONFIG_SOCK_CGROUP_DATA
753 
754 void cgroup_sk_alloc(struct sock_cgroup_data *skcd);
755 void cgroup_sk_clone(struct sock_cgroup_data *skcd);
756 void cgroup_sk_free(struct sock_cgroup_data *skcd);
757 
sock_cgroup_ptr(struct sock_cgroup_data * skcd)758 static inline struct cgroup *sock_cgroup_ptr(struct sock_cgroup_data *skcd)
759 {
760 	return skcd->cgroup;
761 }
762 
763 #else	/* CONFIG_CGROUP_DATA */
764 
cgroup_sk_alloc(struct sock_cgroup_data * skcd)765 static inline void cgroup_sk_alloc(struct sock_cgroup_data *skcd) {}
cgroup_sk_clone(struct sock_cgroup_data * skcd)766 static inline void cgroup_sk_clone(struct sock_cgroup_data *skcd) {}
cgroup_sk_free(struct sock_cgroup_data * skcd)767 static inline void cgroup_sk_free(struct sock_cgroup_data *skcd) {}
768 
769 #endif	/* CONFIG_CGROUP_DATA */
770 
771 struct cgroup_namespace {
772 	struct ns_common	ns;
773 	struct user_namespace	*user_ns;
774 	struct ucounts		*ucounts;
775 	struct css_set          *root_cset;
776 };
777 
778 extern struct cgroup_namespace init_cgroup_ns;
779 
780 #ifdef CONFIG_CGROUPS
781 
782 void free_cgroup_ns(struct cgroup_namespace *ns);
783 
784 struct cgroup_namespace *copy_cgroup_ns(unsigned long flags,
785 					struct user_namespace *user_ns,
786 					struct cgroup_namespace *old_ns);
787 
788 int cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
789 		   struct cgroup_namespace *ns);
790 
791 #else /* !CONFIG_CGROUPS */
792 
free_cgroup_ns(struct cgroup_namespace * ns)793 static inline void free_cgroup_ns(struct cgroup_namespace *ns) { }
794 static inline struct cgroup_namespace *
copy_cgroup_ns(unsigned long flags,struct user_namespace * user_ns,struct cgroup_namespace * old_ns)795 copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
796 	       struct cgroup_namespace *old_ns)
797 {
798 	return old_ns;
799 }
800 
801 #endif /* !CONFIG_CGROUPS */
802 
get_cgroup_ns(struct cgroup_namespace * ns)803 static inline void get_cgroup_ns(struct cgroup_namespace *ns)
804 {
805 	if (ns)
806 		refcount_inc(&ns->ns.count);
807 }
808 
put_cgroup_ns(struct cgroup_namespace * ns)809 static inline void put_cgroup_ns(struct cgroup_namespace *ns)
810 {
811 	if (ns && refcount_dec_and_test(&ns->ns.count))
812 		free_cgroup_ns(ns);
813 }
814 
815 #ifdef CONFIG_CGROUPS
816 
817 void cgroup_enter_frozen(void);
818 void cgroup_leave_frozen(bool always_leave);
819 void cgroup_update_frozen(struct cgroup *cgrp);
820 void cgroup_freeze(struct cgroup *cgrp, bool freeze);
821 void cgroup_freezer_migrate_task(struct task_struct *task, struct cgroup *src,
822 				 struct cgroup *dst);
823 
cgroup_task_frozen(struct task_struct * task)824 static inline bool cgroup_task_frozen(struct task_struct *task)
825 {
826 	return task->frozen;
827 }
828 
829 #else /* !CONFIG_CGROUPS */
830 
cgroup_enter_frozen(void)831 static inline void cgroup_enter_frozen(void) { }
cgroup_leave_frozen(bool always_leave)832 static inline void cgroup_leave_frozen(bool always_leave) { }
cgroup_task_frozen(struct task_struct * task)833 static inline bool cgroup_task_frozen(struct task_struct *task)
834 {
835 	return false;
836 }
837 
838 #endif /* !CONFIG_CGROUPS */
839 
840 #ifdef CONFIG_CGROUP_BPF
cgroup_bpf_get(struct cgroup * cgrp)841 static inline void cgroup_bpf_get(struct cgroup *cgrp)
842 {
843 	percpu_ref_get(&cgrp->bpf.refcnt);
844 }
845 
cgroup_bpf_put(struct cgroup * cgrp)846 static inline void cgroup_bpf_put(struct cgroup *cgrp)
847 {
848 	percpu_ref_put(&cgrp->bpf.refcnt);
849 }
850 
851 #else /* CONFIG_CGROUP_BPF */
852 
cgroup_bpf_get(struct cgroup * cgrp)853 static inline void cgroup_bpf_get(struct cgroup *cgrp) {}
cgroup_bpf_put(struct cgroup * cgrp)854 static inline void cgroup_bpf_put(struct cgroup *cgrp) {}
855 
856 #endif /* CONFIG_CGROUP_BPF */
857 
858 #endif /* _LINUX_CGROUP_H */
859