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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 hierarhcy 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 
111 int cgroup_attach_task_all(struct task_struct *from, struct task_struct *);
112 int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from);
113 
114 int cgroup_add_dfl_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
115 int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
116 int cgroup_rm_cftypes(struct cftype *cfts);
117 void cgroup_file_notify(struct cgroup_file *cfile);
118 
119 int task_cgroup_path(struct task_struct *task, char *buf, size_t buflen);
120 int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry);
121 int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
122 		     struct pid *pid, struct task_struct *tsk);
123 
124 void cgroup_fork(struct task_struct *p);
125 extern int cgroup_can_fork(struct task_struct *p,
126 			   struct kernel_clone_args *kargs);
127 extern void cgroup_cancel_fork(struct task_struct *p,
128 			       struct kernel_clone_args *kargs);
129 extern void cgroup_post_fork(struct task_struct *p,
130 			     struct kernel_clone_args *kargs);
131 void cgroup_exit(struct task_struct *p);
132 void cgroup_release(struct task_struct *p);
133 void cgroup_free(struct task_struct *p);
134 
135 int cgroup_init_early(void);
136 int cgroup_init(void);
137 
138 int cgroup_parse_float(const char *input, unsigned dec_shift, s64 *v);
139 
140 /*
141  * Iteration helpers and macros.
142  */
143 
144 struct cgroup_subsys_state *css_next_child(struct cgroup_subsys_state *pos,
145 					   struct cgroup_subsys_state *parent);
146 struct cgroup_subsys_state *css_next_descendant_pre(struct cgroup_subsys_state *pos,
147 						    struct cgroup_subsys_state *css);
148 struct cgroup_subsys_state *css_rightmost_descendant(struct cgroup_subsys_state *pos);
149 struct cgroup_subsys_state *css_next_descendant_post(struct cgroup_subsys_state *pos,
150 						     struct cgroup_subsys_state *css);
151 
152 struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset,
153 					 struct cgroup_subsys_state **dst_cssp);
154 struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset,
155 					struct cgroup_subsys_state **dst_cssp);
156 
157 void css_task_iter_start(struct cgroup_subsys_state *css, unsigned int flags,
158 			 struct css_task_iter *it);
159 struct task_struct *css_task_iter_next(struct css_task_iter *it);
160 void css_task_iter_end(struct css_task_iter *it);
161 
162 /**
163  * css_for_each_child - iterate through children of a css
164  * @pos: the css * to use as the loop cursor
165  * @parent: css whose children to walk
166  *
167  * Walk @parent's children.  Must be called under rcu_read_lock().
168  *
169  * If a subsystem synchronizes ->css_online() and the start of iteration, a
170  * css which finished ->css_online() is guaranteed to be visible in the
171  * future iterations and will stay visible until the last reference is put.
172  * A css which hasn't finished ->css_online() or already finished
173  * ->css_offline() may show up during traversal.  It's each subsystem's
174  * responsibility to synchronize against on/offlining.
175  *
176  * It is allowed to temporarily drop RCU read lock during iteration.  The
177  * caller is responsible for ensuring that @pos remains accessible until
178  * the start of the next iteration by, for example, bumping the css refcnt.
179  */
180 #define css_for_each_child(pos, parent)					\
181 	for ((pos) = css_next_child(NULL, (parent)); (pos);		\
182 	     (pos) = css_next_child((pos), (parent)))
183 
184 /**
185  * css_for_each_descendant_pre - pre-order walk of a css's descendants
186  * @pos: the css * to use as the loop cursor
187  * @root: css whose descendants to walk
188  *
189  * Walk @root's descendants.  @root is included in the iteration and the
190  * first node to be visited.  Must be called under rcu_read_lock().
191  *
192  * If a subsystem synchronizes ->css_online() and the start of iteration, a
193  * css which finished ->css_online() is guaranteed to be visible in the
194  * future iterations and will stay visible until the last reference is put.
195  * A css which hasn't finished ->css_online() or already finished
196  * ->css_offline() may show up during traversal.  It's each subsystem's
197  * responsibility to synchronize against on/offlining.
198  *
199  * For example, the following guarantees that a descendant can't escape
200  * state updates of its ancestors.
201  *
202  * my_online(@css)
203  * {
204  *	Lock @css's parent and @css;
205  *	Inherit state from the parent;
206  *	Unlock both.
207  * }
208  *
209  * my_update_state(@css)
210  * {
211  *	css_for_each_descendant_pre(@pos, @css) {
212  *		Lock @pos;
213  *		if (@pos == @css)
214  *			Update @css's state;
215  *		else
216  *			Verify @pos is alive and inherit state from its parent;
217  *		Unlock @pos;
218  *	}
219  * }
220  *
221  * As long as the inheriting step, including checking the parent state, is
222  * enclosed inside @pos locking, double-locking the parent isn't necessary
223  * while inheriting.  The state update to the parent is guaranteed to be
224  * visible by walking order and, as long as inheriting operations to the
225  * same @pos are atomic to each other, multiple updates racing each other
226  * still result in the correct state.  It's guaranateed that at least one
227  * inheritance happens for any css after the latest update to its parent.
228  *
229  * If checking parent's state requires locking the parent, each inheriting
230  * iteration should lock and unlock both @pos->parent and @pos.
231  *
232  * Alternatively, a subsystem may choose to use a single global lock to
233  * synchronize ->css_online() and ->css_offline() against tree-walking
234  * operations.
235  *
236  * It is allowed to temporarily drop RCU read lock during iteration.  The
237  * caller is responsible for ensuring that @pos remains accessible until
238  * the start of the next iteration by, for example, bumping the css refcnt.
239  */
240 #define css_for_each_descendant_pre(pos, css)				\
241 	for ((pos) = css_next_descendant_pre(NULL, (css)); (pos);	\
242 	     (pos) = css_next_descendant_pre((pos), (css)))
243 
244 /**
245  * css_for_each_descendant_post - post-order walk of a css's descendants
246  * @pos: the css * to use as the loop cursor
247  * @css: css whose descendants to walk
248  *
249  * Similar to css_for_each_descendant_pre() but performs post-order
250  * traversal instead.  @root is included in the iteration and the last
251  * node to be visited.
252  *
253  * If a subsystem synchronizes ->css_online() and the start of iteration, a
254  * css which finished ->css_online() is guaranteed to be visible in the
255  * future iterations and will stay visible until the last reference is put.
256  * A css which hasn't finished ->css_online() or already finished
257  * ->css_offline() may show up during traversal.  It's each subsystem's
258  * responsibility to synchronize against on/offlining.
259  *
260  * Note that the walk visibility guarantee example described in pre-order
261  * walk doesn't apply the same to post-order walks.
262  */
263 #define css_for_each_descendant_post(pos, css)				\
264 	for ((pos) = css_next_descendant_post(NULL, (css)); (pos);	\
265 	     (pos) = css_next_descendant_post((pos), (css)))
266 
267 /**
268  * cgroup_taskset_for_each - iterate cgroup_taskset
269  * @task: the loop cursor
270  * @dst_css: the destination css
271  * @tset: taskset to iterate
272  *
273  * @tset may contain multiple tasks and they may belong to multiple
274  * processes.
275  *
276  * On the v2 hierarchy, there may be tasks from multiple processes and they
277  * may not share the source or destination csses.
278  *
279  * On traditional hierarchies, when there are multiple tasks in @tset, if a
280  * task of a process is in @tset, all tasks of the process are in @tset.
281  * Also, all are guaranteed to share the same source and destination csses.
282  *
283  * Iteration is not in any specific order.
284  */
285 #define cgroup_taskset_for_each(task, dst_css, tset)			\
286 	for ((task) = cgroup_taskset_first((tset), &(dst_css));		\
287 	     (task);							\
288 	     (task) = cgroup_taskset_next((tset), &(dst_css)))
289 
290 /**
291  * cgroup_taskset_for_each_leader - iterate group leaders in a cgroup_taskset
292  * @leader: the loop cursor
293  * @dst_css: the destination css
294  * @tset: taskset to iterate
295  *
296  * Iterate threadgroup leaders of @tset.  For single-task migrations, @tset
297  * may not contain any.
298  */
299 #define cgroup_taskset_for_each_leader(leader, dst_css, tset)		\
300 	for ((leader) = cgroup_taskset_first((tset), &(dst_css));	\
301 	     (leader);							\
302 	     (leader) = cgroup_taskset_next((tset), &(dst_css)))	\
303 		if ((leader) != (leader)->group_leader)			\
304 			;						\
305 		else
306 
307 /*
308  * Inline functions.
309  */
310 
cgroup_id(struct cgroup * cgrp)311 static inline u64 cgroup_id(struct cgroup *cgrp)
312 {
313 	return cgrp->kn->id;
314 }
315 
316 /**
317  * css_get - obtain a reference on the specified css
318  * @css: target css
319  *
320  * The caller must already have a reference.
321  */
css_get(struct cgroup_subsys_state * css)322 static inline void css_get(struct cgroup_subsys_state *css)
323 {
324 	if (!(css->flags & CSS_NO_REF))
325 		percpu_ref_get(&css->refcnt);
326 }
327 
328 /**
329  * css_get_many - obtain references on the specified css
330  * @css: target css
331  * @n: number of references to get
332  *
333  * The caller must already have a reference.
334  */
css_get_many(struct cgroup_subsys_state * css,unsigned int n)335 static inline void css_get_many(struct cgroup_subsys_state *css, unsigned int n)
336 {
337 	if (!(css->flags & CSS_NO_REF))
338 		percpu_ref_get_many(&css->refcnt, n);
339 }
340 
341 /**
342  * css_tryget - try to obtain a reference on the specified css
343  * @css: target css
344  *
345  * Obtain a reference on @css unless it already has reached zero and is
346  * being released.  This function doesn't care whether @css is on or
347  * offline.  The caller naturally needs to ensure that @css is accessible
348  * but doesn't have to be holding a reference on it - IOW, RCU protected
349  * access is good enough for this function.  Returns %true if a reference
350  * count was successfully obtained; %false otherwise.
351  */
css_tryget(struct cgroup_subsys_state * css)352 static inline bool css_tryget(struct cgroup_subsys_state *css)
353 {
354 	if (!(css->flags & CSS_NO_REF))
355 		return percpu_ref_tryget(&css->refcnt);
356 	return true;
357 }
358 
359 /**
360  * css_tryget_online - try to obtain a reference on the specified css if online
361  * @css: target css
362  *
363  * Obtain a reference on @css if it's online.  The caller naturally needs
364  * to ensure that @css is accessible but doesn't have to be holding a
365  * reference on it - IOW, RCU protected access is good enough for this
366  * function.  Returns %true if a reference count was successfully obtained;
367  * %false otherwise.
368  */
css_tryget_online(struct cgroup_subsys_state * css)369 static inline bool css_tryget_online(struct cgroup_subsys_state *css)
370 {
371 	if (!(css->flags & CSS_NO_REF))
372 		return percpu_ref_tryget_live(&css->refcnt);
373 	return true;
374 }
375 
376 /**
377  * css_is_dying - test whether the specified css is dying
378  * @css: target css
379  *
380  * Test whether @css is in the process of offlining or already offline.  In
381  * most cases, ->css_online() and ->css_offline() callbacks should be
382  * enough; however, the actual offline operations are RCU delayed and this
383  * test returns %true also when @css is scheduled to be offlined.
384  *
385  * This is useful, for example, when the use case requires synchronous
386  * behavior with respect to cgroup removal.  cgroup removal schedules css
387  * offlining but the css can seem alive while the operation is being
388  * delayed.  If the delay affects user visible semantics, this test can be
389  * used to resolve the situation.
390  */
css_is_dying(struct cgroup_subsys_state * css)391 static inline bool css_is_dying(struct cgroup_subsys_state *css)
392 {
393 	return !(css->flags & CSS_NO_REF) && percpu_ref_is_dying(&css->refcnt);
394 }
395 
396 /**
397  * css_put - put a css reference
398  * @css: target css
399  *
400  * Put a reference obtained via css_get() and css_tryget_online().
401  */
css_put(struct cgroup_subsys_state * css)402 static inline void css_put(struct cgroup_subsys_state *css)
403 {
404 	if (!(css->flags & CSS_NO_REF))
405 		percpu_ref_put(&css->refcnt);
406 }
407 
408 /**
409  * css_put_many - put css references
410  * @css: target css
411  * @n: number of references to put
412  *
413  * Put references obtained via css_get() and css_tryget_online().
414  */
css_put_many(struct cgroup_subsys_state * css,unsigned int n)415 static inline void css_put_many(struct cgroup_subsys_state *css, unsigned int n)
416 {
417 	if (!(css->flags & CSS_NO_REF))
418 		percpu_ref_put_many(&css->refcnt, n);
419 }
420 
cgroup_get(struct cgroup * cgrp)421 static inline void cgroup_get(struct cgroup *cgrp)
422 {
423 	css_get(&cgrp->self);
424 }
425 
cgroup_tryget(struct cgroup * cgrp)426 static inline bool cgroup_tryget(struct cgroup *cgrp)
427 {
428 	return css_tryget(&cgrp->self);
429 }
430 
cgroup_put(struct cgroup * cgrp)431 static inline void cgroup_put(struct cgroup *cgrp)
432 {
433 	css_put(&cgrp->self);
434 }
435 
436 /**
437  * task_css_set_check - obtain a task's css_set with extra access conditions
438  * @task: the task to obtain css_set for
439  * @__c: extra condition expression to be passed to rcu_dereference_check()
440  *
441  * A task's css_set is RCU protected, initialized and exited while holding
442  * task_lock(), and can only be modified while holding both cgroup_mutex
443  * and task_lock() while the task is alive.  This macro verifies that the
444  * caller is inside proper critical section and returns @task's css_set.
445  *
446  * The caller can also specify additional allowed conditions via @__c, such
447  * as locks used during the cgroup_subsys::attach() methods.
448  */
449 #ifdef CONFIG_PROVE_RCU
450 extern struct mutex cgroup_mutex;
451 extern spinlock_t css_set_lock;
452 #define task_css_set_check(task, __c)					\
453 	rcu_dereference_check((task)->cgroups,				\
454 		lockdep_is_held(&cgroup_mutex) ||			\
455 		lockdep_is_held(&css_set_lock) ||			\
456 		((task)->flags & PF_EXITING) || (__c))
457 #else
458 #define task_css_set_check(task, __c)					\
459 	rcu_dereference((task)->cgroups)
460 #endif
461 
462 /**
463  * task_css_check - obtain css for (task, subsys) w/ extra access conds
464  * @task: the target task
465  * @subsys_id: the target subsystem ID
466  * @__c: extra condition expression to be passed to rcu_dereference_check()
467  *
468  * Return the cgroup_subsys_state for the (@task, @subsys_id) pair.  The
469  * synchronization rules are the same as task_css_set_check().
470  */
471 #define task_css_check(task, subsys_id, __c)				\
472 	task_css_set_check((task), (__c))->subsys[(subsys_id)]
473 
474 /**
475  * task_css_set - obtain a task's css_set
476  * @task: the task to obtain css_set for
477  *
478  * See task_css_set_check().
479  */
task_css_set(struct task_struct * task)480 static inline struct css_set *task_css_set(struct task_struct *task)
481 {
482 	return task_css_set_check(task, false);
483 }
484 
485 /**
486  * task_css - obtain css for (task, subsys)
487  * @task: the target task
488  * @subsys_id: the target subsystem ID
489  *
490  * See task_css_check().
491  */
task_css(struct task_struct * task,int subsys_id)492 static inline struct cgroup_subsys_state *task_css(struct task_struct *task,
493 						   int subsys_id)
494 {
495 	return task_css_check(task, subsys_id, false);
496 }
497 
498 /**
499  * task_get_css - find and get the css for (task, subsys)
500  * @task: the target task
501  * @subsys_id: the target subsystem ID
502  *
503  * Find the css for the (@task, @subsys_id) combination, increment a
504  * reference on and return it.  This function is guaranteed to return a
505  * valid css.  The returned css may already have been offlined.
506  */
507 static inline struct cgroup_subsys_state *
task_get_css(struct task_struct * task,int subsys_id)508 task_get_css(struct task_struct *task, int subsys_id)
509 {
510 	struct cgroup_subsys_state *css;
511 
512 	rcu_read_lock();
513 	while (true) {
514 		css = task_css(task, subsys_id);
515 		/*
516 		 * Can't use css_tryget_online() here.  A task which has
517 		 * PF_EXITING set may stay associated with an offline css.
518 		 * If such task calls this function, css_tryget_online()
519 		 * will keep failing.
520 		 */
521 		if (likely(css_tryget(css)))
522 			break;
523 		cpu_relax();
524 	}
525 	rcu_read_unlock();
526 	return css;
527 }
528 
529 /**
530  * task_css_is_root - test whether a task belongs to the root css
531  * @task: the target task
532  * @subsys_id: the target subsystem ID
533  *
534  * Test whether @task belongs to the root css on the specified subsystem.
535  * May be invoked in any context.
536  */
task_css_is_root(struct task_struct * task,int subsys_id)537 static inline bool task_css_is_root(struct task_struct *task, int subsys_id)
538 {
539 	return task_css_check(task, subsys_id, true) ==
540 		init_css_set.subsys[subsys_id];
541 }
542 
task_cgroup(struct task_struct * task,int subsys_id)543 static inline struct cgroup *task_cgroup(struct task_struct *task,
544 					 int subsys_id)
545 {
546 	return task_css(task, subsys_id)->cgroup;
547 }
548 
task_dfl_cgroup(struct task_struct * task)549 static inline struct cgroup *task_dfl_cgroup(struct task_struct *task)
550 {
551 	return task_css_set(task)->dfl_cgrp;
552 }
553 
cgroup_parent(struct cgroup * cgrp)554 static inline struct cgroup *cgroup_parent(struct cgroup *cgrp)
555 {
556 	struct cgroup_subsys_state *parent_css = cgrp->self.parent;
557 
558 	if (parent_css)
559 		return container_of(parent_css, struct cgroup, self);
560 	return NULL;
561 }
562 
563 /**
564  * cgroup_is_descendant - test ancestry
565  * @cgrp: the cgroup to be tested
566  * @ancestor: possible ancestor of @cgrp
567  *
568  * Test whether @cgrp is a descendant of @ancestor.  It also returns %true
569  * if @cgrp == @ancestor.  This function is safe to call as long as @cgrp
570  * and @ancestor are accessible.
571  */
cgroup_is_descendant(struct cgroup * cgrp,struct cgroup * ancestor)572 static inline bool cgroup_is_descendant(struct cgroup *cgrp,
573 					struct cgroup *ancestor)
574 {
575 	if (cgrp->root != ancestor->root || cgrp->level < ancestor->level)
576 		return false;
577 	return cgrp->ancestor_ids[ancestor->level] == cgroup_id(ancestor);
578 }
579 
580 /**
581  * cgroup_ancestor - find ancestor of cgroup
582  * @cgrp: cgroup to find ancestor of
583  * @ancestor_level: level of ancestor to find starting from root
584  *
585  * Find ancestor of cgroup at specified level starting from root if it exists
586  * and return pointer to it. Return NULL if @cgrp doesn't have ancestor at
587  * @ancestor_level.
588  *
589  * This function is safe to call as long as @cgrp is accessible.
590  */
cgroup_ancestor(struct cgroup * cgrp,int ancestor_level)591 static inline struct cgroup *cgroup_ancestor(struct cgroup *cgrp,
592 					     int ancestor_level)
593 {
594 	if (cgrp->level < ancestor_level)
595 		return NULL;
596 	while (cgrp && cgrp->level > ancestor_level)
597 		cgrp = cgroup_parent(cgrp);
598 	return cgrp;
599 }
600 
601 /**
602  * task_under_cgroup_hierarchy - test task's membership of cgroup ancestry
603  * @task: the task to be tested
604  * @ancestor: possible ancestor of @task's cgroup
605  *
606  * Tests whether @task's default cgroup hierarchy is a descendant of @ancestor.
607  * It follows all the same rules as cgroup_is_descendant, and only applies
608  * to the default hierarchy.
609  */
task_under_cgroup_hierarchy(struct task_struct * task,struct cgroup * ancestor)610 static inline bool task_under_cgroup_hierarchy(struct task_struct *task,
611 					       struct cgroup *ancestor)
612 {
613 	struct css_set *cset = task_css_set(task);
614 
615 	return cgroup_is_descendant(cset->dfl_cgrp, ancestor);
616 }
617 
618 /* no synchronization, the result can only be used as a hint */
cgroup_is_populated(struct cgroup * cgrp)619 static inline bool cgroup_is_populated(struct cgroup *cgrp)
620 {
621 	return cgrp->nr_populated_csets + cgrp->nr_populated_domain_children +
622 		cgrp->nr_populated_threaded_children;
623 }
624 
625 /* returns ino associated with a cgroup */
cgroup_ino(struct cgroup * cgrp)626 static inline ino_t cgroup_ino(struct cgroup *cgrp)
627 {
628 	return kernfs_ino(cgrp->kn);
629 }
630 
631 /* cft/css accessors for cftype->write() operation */
of_cft(struct kernfs_open_file * of)632 static inline struct cftype *of_cft(struct kernfs_open_file *of)
633 {
634 	return of->kn->priv;
635 }
636 
637 struct cgroup_subsys_state *of_css(struct kernfs_open_file *of);
638 
639 /* cft/css accessors for cftype->seq_*() operations */
seq_cft(struct seq_file * seq)640 static inline struct cftype *seq_cft(struct seq_file *seq)
641 {
642 	return of_cft(seq->private);
643 }
644 
seq_css(struct seq_file * seq)645 static inline struct cgroup_subsys_state *seq_css(struct seq_file *seq)
646 {
647 	return of_css(seq->private);
648 }
649 
650 /*
651  * Name / path handling functions.  All are thin wrappers around the kernfs
652  * counterparts and can be called under any context.
653  */
654 
cgroup_name(struct cgroup * cgrp,char * buf,size_t buflen)655 static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen)
656 {
657 	return kernfs_name(cgrp->kn, buf, buflen);
658 }
659 
cgroup_path(struct cgroup * cgrp,char * buf,size_t buflen)660 static inline int cgroup_path(struct cgroup *cgrp, char *buf, size_t buflen)
661 {
662 	return kernfs_path(cgrp->kn, buf, buflen);
663 }
664 
pr_cont_cgroup_name(struct cgroup * cgrp)665 static inline void pr_cont_cgroup_name(struct cgroup *cgrp)
666 {
667 	pr_cont_kernfs_name(cgrp->kn);
668 }
669 
pr_cont_cgroup_path(struct cgroup * cgrp)670 static inline void pr_cont_cgroup_path(struct cgroup *cgrp)
671 {
672 	pr_cont_kernfs_path(cgrp->kn);
673 }
674 
cgroup_psi(struct cgroup * cgrp)675 static inline struct psi_group *cgroup_psi(struct cgroup *cgrp)
676 {
677 	return &cgrp->psi;
678 }
679 
cgroup_init_kthreadd(void)680 static inline void cgroup_init_kthreadd(void)
681 {
682 	/*
683 	 * kthreadd is inherited by all kthreads, keep it in the root so
684 	 * that the new kthreads are guaranteed to stay in the root until
685 	 * initialization is finished.
686 	 */
687 	current->no_cgroup_migration = 1;
688 }
689 
cgroup_kthread_ready(void)690 static inline void cgroup_kthread_ready(void)
691 {
692 	/*
693 	 * This kthread finished initialization.  The creator should have
694 	 * set PF_NO_SETAFFINITY if this kthread should stay in the root.
695 	 */
696 	current->no_cgroup_migration = 0;
697 }
698 
699 void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen);
700 #else /* !CONFIG_CGROUPS */
701 
702 struct cgroup_subsys_state;
703 struct cgroup;
704 
cgroup_id(struct cgroup * cgrp)705 static inline u64 cgroup_id(struct cgroup *cgrp) { return 1; }
css_get(struct cgroup_subsys_state * css)706 static inline void css_get(struct cgroup_subsys_state *css) {}
css_put(struct cgroup_subsys_state * css)707 static inline void css_put(struct cgroup_subsys_state *css) {}
cgroup_attach_task_all(struct task_struct * from,struct task_struct * t)708 static inline int cgroup_attach_task_all(struct task_struct *from,
709 					 struct task_struct *t) { return 0; }
cgroupstats_build(struct cgroupstats * stats,struct dentry * dentry)710 static inline int cgroupstats_build(struct cgroupstats *stats,
711 				    struct dentry *dentry) { return -EINVAL; }
712 
cgroup_fork(struct task_struct * p)713 static inline void cgroup_fork(struct task_struct *p) {}
cgroup_can_fork(struct task_struct * p,struct kernel_clone_args * kargs)714 static inline int cgroup_can_fork(struct task_struct *p,
715 				  struct kernel_clone_args *kargs) { return 0; }
cgroup_cancel_fork(struct task_struct * p,struct kernel_clone_args * kargs)716 static inline void cgroup_cancel_fork(struct task_struct *p,
717 				      struct kernel_clone_args *kargs) {}
cgroup_post_fork(struct task_struct * p,struct kernel_clone_args * kargs)718 static inline void cgroup_post_fork(struct task_struct *p,
719 				    struct kernel_clone_args *kargs) {}
cgroup_exit(struct task_struct * p)720 static inline void cgroup_exit(struct task_struct *p) {}
cgroup_release(struct task_struct * p)721 static inline void cgroup_release(struct task_struct *p) {}
cgroup_free(struct task_struct * p)722 static inline void cgroup_free(struct task_struct *p) {}
723 
cgroup_init_early(void)724 static inline int cgroup_init_early(void) { return 0; }
cgroup_init(void)725 static inline int cgroup_init(void) { return 0; }
cgroup_init_kthreadd(void)726 static inline void cgroup_init_kthreadd(void) {}
cgroup_kthread_ready(void)727 static inline void cgroup_kthread_ready(void) {}
728 
cgroup_parent(struct cgroup * cgrp)729 static inline struct cgroup *cgroup_parent(struct cgroup *cgrp)
730 {
731 	return NULL;
732 }
733 
cgroup_psi(struct cgroup * cgrp)734 static inline struct psi_group *cgroup_psi(struct cgroup *cgrp)
735 {
736 	return NULL;
737 }
738 
task_under_cgroup_hierarchy(struct task_struct * task,struct cgroup * ancestor)739 static inline bool task_under_cgroup_hierarchy(struct task_struct *task,
740 					       struct cgroup *ancestor)
741 {
742 	return true;
743 }
744 
cgroup_path_from_kernfs_id(u64 id,char * buf,size_t buflen)745 static inline void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen)
746 {}
747 #endif /* !CONFIG_CGROUPS */
748 
749 #ifdef CONFIG_CGROUPS
750 /*
751  * cgroup scalable recursive statistics.
752  */
753 void cgroup_rstat_updated(struct cgroup *cgrp, int cpu);
754 void cgroup_rstat_flush(struct cgroup *cgrp);
755 void cgroup_rstat_flush_irqsafe(struct cgroup *cgrp);
756 void cgroup_rstat_flush_hold(struct cgroup *cgrp);
757 void cgroup_rstat_flush_release(void);
758 
759 /*
760  * Basic resource stats.
761  */
762 #ifdef CONFIG_CGROUP_CPUACCT
763 void cpuacct_charge(struct task_struct *tsk, u64 cputime);
764 void cpuacct_account_field(struct task_struct *tsk, int index, u64 val);
765 #else
cpuacct_charge(struct task_struct * tsk,u64 cputime)766 static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
cpuacct_account_field(struct task_struct * tsk,int index,u64 val)767 static inline void cpuacct_account_field(struct task_struct *tsk, int index,
768 					 u64 val) {}
769 #endif
770 
771 void __cgroup_account_cputime(struct cgroup *cgrp, u64 delta_exec);
772 void __cgroup_account_cputime_field(struct cgroup *cgrp,
773 				    enum cpu_usage_stat index, u64 delta_exec);
774 
cgroup_account_cputime(struct task_struct * task,u64 delta_exec)775 static inline void cgroup_account_cputime(struct task_struct *task,
776 					  u64 delta_exec)
777 {
778 	struct cgroup *cgrp;
779 
780 	cpuacct_charge(task, delta_exec);
781 
782 	rcu_read_lock();
783 	cgrp = task_dfl_cgroup(task);
784 	if (cgroup_parent(cgrp))
785 		__cgroup_account_cputime(cgrp, delta_exec);
786 	rcu_read_unlock();
787 }
788 
cgroup_account_cputime_field(struct task_struct * task,enum cpu_usage_stat index,u64 delta_exec)789 static inline void cgroup_account_cputime_field(struct task_struct *task,
790 						enum cpu_usage_stat index,
791 						u64 delta_exec)
792 {
793 	struct cgroup *cgrp;
794 
795 	cpuacct_account_field(task, index, delta_exec);
796 
797 	rcu_read_lock();
798 	cgrp = task_dfl_cgroup(task);
799 	if (cgroup_parent(cgrp))
800 		__cgroup_account_cputime_field(cgrp, index, delta_exec);
801 	rcu_read_unlock();
802 }
803 
804 #else	/* CONFIG_CGROUPS */
805 
cgroup_account_cputime(struct task_struct * task,u64 delta_exec)806 static inline void cgroup_account_cputime(struct task_struct *task,
807 					  u64 delta_exec) {}
cgroup_account_cputime_field(struct task_struct * task,enum cpu_usage_stat index,u64 delta_exec)808 static inline void cgroup_account_cputime_field(struct task_struct *task,
809 						enum cpu_usage_stat index,
810 						u64 delta_exec) {}
811 
812 #endif	/* CONFIG_CGROUPS */
813 
814 /*
815  * sock->sk_cgrp_data handling.  For more info, see sock_cgroup_data
816  * definition in cgroup-defs.h.
817  */
818 #ifdef CONFIG_SOCK_CGROUP_DATA
819 
820 void cgroup_sk_alloc(struct sock_cgroup_data *skcd);
821 void cgroup_sk_clone(struct sock_cgroup_data *skcd);
822 void cgroup_sk_free(struct sock_cgroup_data *skcd);
823 
sock_cgroup_ptr(struct sock_cgroup_data * skcd)824 static inline struct cgroup *sock_cgroup_ptr(struct sock_cgroup_data *skcd)
825 {
826 	return skcd->cgroup;
827 }
828 
829 #else	/* CONFIG_CGROUP_DATA */
830 
cgroup_sk_alloc(struct sock_cgroup_data * skcd)831 static inline void cgroup_sk_alloc(struct sock_cgroup_data *skcd) {}
cgroup_sk_clone(struct sock_cgroup_data * skcd)832 static inline void cgroup_sk_clone(struct sock_cgroup_data *skcd) {}
cgroup_sk_free(struct sock_cgroup_data * skcd)833 static inline void cgroup_sk_free(struct sock_cgroup_data *skcd) {}
834 
835 #endif	/* CONFIG_CGROUP_DATA */
836 
837 struct cgroup_namespace {
838 	refcount_t		count;
839 	struct ns_common	ns;
840 	struct user_namespace	*user_ns;
841 	struct ucounts		*ucounts;
842 	struct css_set          *root_cset;
843 };
844 
845 extern struct cgroup_namespace init_cgroup_ns;
846 
847 #ifdef CONFIG_CGROUPS
848 
849 void free_cgroup_ns(struct cgroup_namespace *ns);
850 
851 struct cgroup_namespace *copy_cgroup_ns(unsigned long flags,
852 					struct user_namespace *user_ns,
853 					struct cgroup_namespace *old_ns);
854 
855 int cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
856 		   struct cgroup_namespace *ns);
857 
858 #else /* !CONFIG_CGROUPS */
859 
free_cgroup_ns(struct cgroup_namespace * ns)860 static inline void free_cgroup_ns(struct cgroup_namespace *ns) { }
861 static inline struct cgroup_namespace *
copy_cgroup_ns(unsigned long flags,struct user_namespace * user_ns,struct cgroup_namespace * old_ns)862 copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
863 	       struct cgroup_namespace *old_ns)
864 {
865 	return old_ns;
866 }
867 
868 #endif /* !CONFIG_CGROUPS */
869 
get_cgroup_ns(struct cgroup_namespace * ns)870 static inline void get_cgroup_ns(struct cgroup_namespace *ns)
871 {
872 	if (ns)
873 		refcount_inc(&ns->count);
874 }
875 
put_cgroup_ns(struct cgroup_namespace * ns)876 static inline void put_cgroup_ns(struct cgroup_namespace *ns)
877 {
878 	if (ns && refcount_dec_and_test(&ns->count))
879 		free_cgroup_ns(ns);
880 }
881 
882 #ifdef CONFIG_CGROUPS
883 
884 void cgroup_enter_frozen(void);
885 void cgroup_leave_frozen(bool always_leave);
886 void cgroup_update_frozen(struct cgroup *cgrp);
887 void cgroup_freeze(struct cgroup *cgrp, bool freeze);
888 void cgroup_freezer_migrate_task(struct task_struct *task, struct cgroup *src,
889 				 struct cgroup *dst);
890 
cgroup_task_freeze(struct task_struct * task)891 static inline bool cgroup_task_freeze(struct task_struct *task)
892 {
893 	bool ret;
894 
895 	if (task->flags & PF_KTHREAD)
896 		return false;
897 
898 	rcu_read_lock();
899 	ret = test_bit(CGRP_FREEZE, &task_dfl_cgroup(task)->flags);
900 	rcu_read_unlock();
901 
902 	return ret;
903 }
904 
cgroup_task_frozen(struct task_struct * task)905 static inline bool cgroup_task_frozen(struct task_struct *task)
906 {
907 	return task->frozen;
908 }
909 
910 #else /* !CONFIG_CGROUPS */
911 
cgroup_enter_frozen(void)912 static inline void cgroup_enter_frozen(void) { }
cgroup_leave_frozen(bool always_leave)913 static inline void cgroup_leave_frozen(bool always_leave) { }
cgroup_task_freeze(struct task_struct * task)914 static inline bool cgroup_task_freeze(struct task_struct *task)
915 {
916 	return false;
917 }
cgroup_task_frozen(struct task_struct * task)918 static inline bool cgroup_task_frozen(struct task_struct *task)
919 {
920 	return false;
921 }
922 
923 #endif /* !CONFIG_CGROUPS */
924 
925 #ifdef CONFIG_CGROUP_BPF
cgroup_bpf_get(struct cgroup * cgrp)926 static inline void cgroup_bpf_get(struct cgroup *cgrp)
927 {
928 	percpu_ref_get(&cgrp->bpf.refcnt);
929 }
930 
cgroup_bpf_put(struct cgroup * cgrp)931 static inline void cgroup_bpf_put(struct cgroup *cgrp)
932 {
933 	percpu_ref_put(&cgrp->bpf.refcnt);
934 }
935 
936 #else /* CONFIG_CGROUP_BPF */
937 
cgroup_bpf_get(struct cgroup * cgrp)938 static inline void cgroup_bpf_get(struct cgroup *cgrp) {}
cgroup_bpf_put(struct cgroup * cgrp)939 static inline void cgroup_bpf_put(struct cgroup *cgrp) {}
940 
941 #endif /* CONFIG_CGROUP_BPF */
942 
943 #endif /* _LINUX_CGROUP_H */
944