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ddbcc7e8 PM |
1 | #ifndef _LINUX_CGROUP_H |
2 | #define _LINUX_CGROUP_H | |
3 | /* | |
4 | * cgroup interface | |
5 | * | |
6 | * Copyright (C) 2003 BULL SA | |
7 | * Copyright (C) 2004-2006 Silicon Graphics, Inc. | |
8 | * | |
9 | */ | |
10 | ||
11 | #include <linux/sched.h> | |
ddbcc7e8 PM |
12 | #include <linux/cpumask.h> |
13 | #include <linux/nodemask.h> | |
eb6fd504 | 14 | #include <linux/rculist.h> |
846c7bb0 | 15 | #include <linux/cgroupstats.h> |
25a7e684 | 16 | #include <linux/fs.h> |
7da11279 | 17 | #include <linux/seq_file.h> |
2bd59d48 | 18 | #include <linux/kernfs.h> |
49d1dc4b | 19 | #include <linux/jump_label.h> |
a79a908f AK |
20 | #include <linux/nsproxy.h> |
21 | #include <linux/types.h> | |
22 | #include <linux/ns_common.h> | |
23 | #include <linux/nsproxy.h> | |
24 | #include <linux/user_namespace.h> | |
ddbcc7e8 | 25 | |
b4a04ab7 | 26 | #include <linux/cgroup-defs.h> |
ddbcc7e8 PM |
27 | |
28 | #ifdef CONFIG_CGROUPS | |
29 | ||
6abc8ca1 TH |
30 | /* |
31 | * All weight knobs on the default hierarhcy should use the following min, | |
32 | * default and max values. The default value is the logarithmic center of | |
33 | * MIN and MAX and allows 100x to be expressed in both directions. | |
34 | */ | |
35 | #define CGROUP_WEIGHT_MIN 1 | |
36 | #define CGROUP_WEIGHT_DFL 100 | |
37 | #define CGROUP_WEIGHT_MAX 10000 | |
38 | ||
c326aa2b TH |
39 | /* a css_task_iter should be treated as an opaque object */ |
40 | struct css_task_iter { | |
41 | struct cgroup_subsys *ss; | |
42 | ||
43 | struct list_head *cset_pos; | |
44 | struct list_head *cset_head; | |
ddbcc7e8 | 45 | |
c326aa2b TH |
46 | struct list_head *task_pos; |
47 | struct list_head *tasks_head; | |
48 | struct list_head *mg_tasks_head; | |
ed27b9f7 TH |
49 | |
50 | struct css_set *cur_cset; | |
51 | struct task_struct *cur_task; | |
52 | struct list_head iters_node; /* css_set->task_iters */ | |
c326aa2b | 53 | }; |
ddbcc7e8 | 54 | |
c326aa2b TH |
55 | extern struct cgroup_root cgrp_dfl_root; |
56 | extern struct css_set init_css_set; | |
a424316c | 57 | |
c326aa2b | 58 | #define SUBSYS(_x) extern struct cgroup_subsys _x ## _cgrp_subsys; |
817929ec | 59 | #include <linux/cgroup_subsys.h> |
817929ec PM |
60 | #undef SUBSYS |
61 | ||
49d1dc4b TH |
62 | #define SUBSYS(_x) \ |
63 | extern struct static_key_true _x ## _cgrp_subsys_enabled_key; \ | |
64 | extern struct static_key_true _x ## _cgrp_subsys_on_dfl_key; | |
65 | #include <linux/cgroup_subsys.h> | |
66 | #undef SUBSYS | |
67 | ||
68 | /** | |
69 | * cgroup_subsys_enabled - fast test on whether a subsys is enabled | |
70 | * @ss: subsystem in question | |
71 | */ | |
72 | #define cgroup_subsys_enabled(ss) \ | |
73 | static_branch_likely(&ss ## _enabled_key) | |
74 | ||
75 | /** | |
76 | * cgroup_subsys_on_dfl - fast test on whether a subsys is on default hierarchy | |
77 | * @ss: subsystem in question | |
78 | */ | |
79 | #define cgroup_subsys_on_dfl(ss) \ | |
80 | static_branch_likely(&ss ## _on_dfl_key) | |
81 | ||
c326aa2b TH |
82 | bool css_has_online_children(struct cgroup_subsys_state *css); |
83 | struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss); | |
84 | struct cgroup_subsys_state *cgroup_get_e_css(struct cgroup *cgroup, | |
85 | struct cgroup_subsys *ss); | |
86 | struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry, | |
87 | struct cgroup_subsys *ss); | |
88 | ||
16af4396 | 89 | struct cgroup *cgroup_get_from_path(const char *path); |
1f3fe7eb | 90 | struct cgroup *cgroup_get_from_fd(int fd); |
16af4396 | 91 | |
c326aa2b TH |
92 | int cgroup_attach_task_all(struct task_struct *from, struct task_struct *); |
93 | int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from); | |
94 | ||
95 | int cgroup_add_dfl_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); | |
96 | int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); | |
97 | int cgroup_rm_cftypes(struct cftype *cfts); | |
34c06254 | 98 | void cgroup_file_notify(struct cgroup_file *cfile); |
c326aa2b TH |
99 | |
100 | char *task_cgroup_path(struct task_struct *task, char *buf, size_t buflen); | |
101 | int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry); | |
102 | int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns, | |
103 | struct pid *pid, struct task_struct *tsk); | |
104 | ||
105 | void cgroup_fork(struct task_struct *p); | |
b53202e6 ON |
106 | extern int cgroup_can_fork(struct task_struct *p); |
107 | extern void cgroup_cancel_fork(struct task_struct *p); | |
108 | extern void cgroup_post_fork(struct task_struct *p); | |
c326aa2b | 109 | void cgroup_exit(struct task_struct *p); |
2e91fa7f | 110 | void cgroup_free(struct task_struct *p); |
c326aa2b TH |
111 | |
112 | int cgroup_init_early(void); | |
113 | int cgroup_init(void); | |
114 | ||
5c9d535b | 115 | /* |
c326aa2b TH |
116 | * Iteration helpers and macros. |
117 | */ | |
118 | ||
119 | struct cgroup_subsys_state *css_next_child(struct cgroup_subsys_state *pos, | |
120 | struct cgroup_subsys_state *parent); | |
121 | struct cgroup_subsys_state *css_next_descendant_pre(struct cgroup_subsys_state *pos, | |
122 | struct cgroup_subsys_state *css); | |
123 | struct cgroup_subsys_state *css_rightmost_descendant(struct cgroup_subsys_state *pos); | |
124 | struct cgroup_subsys_state *css_next_descendant_post(struct cgroup_subsys_state *pos, | |
125 | struct cgroup_subsys_state *css); | |
126 | ||
1f7dd3e5 TH |
127 | struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset, |
128 | struct cgroup_subsys_state **dst_cssp); | |
129 | struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset, | |
130 | struct cgroup_subsys_state **dst_cssp); | |
c326aa2b TH |
131 | |
132 | void css_task_iter_start(struct cgroup_subsys_state *css, | |
133 | struct css_task_iter *it); | |
134 | struct task_struct *css_task_iter_next(struct css_task_iter *it); | |
135 | void css_task_iter_end(struct css_task_iter *it); | |
136 | ||
137 | /** | |
138 | * css_for_each_child - iterate through children of a css | |
139 | * @pos: the css * to use as the loop cursor | |
140 | * @parent: css whose children to walk | |
141 | * | |
142 | * Walk @parent's children. Must be called under rcu_read_lock(). | |
143 | * | |
144 | * If a subsystem synchronizes ->css_online() and the start of iteration, a | |
145 | * css which finished ->css_online() is guaranteed to be visible in the | |
146 | * future iterations and will stay visible until the last reference is put. | |
147 | * A css which hasn't finished ->css_online() or already finished | |
148 | * ->css_offline() may show up during traversal. It's each subsystem's | |
149 | * responsibility to synchronize against on/offlining. | |
5c9d535b | 150 | * |
c326aa2b TH |
151 | * It is allowed to temporarily drop RCU read lock during iteration. The |
152 | * caller is responsible for ensuring that @pos remains accessible until | |
153 | * the start of the next iteration by, for example, bumping the css refcnt. | |
5c9d535b | 154 | */ |
c326aa2b TH |
155 | #define css_for_each_child(pos, parent) \ |
156 | for ((pos) = css_next_child(NULL, (parent)); (pos); \ | |
157 | (pos) = css_next_child((pos), (parent))) | |
ddbcc7e8 | 158 | |
c326aa2b TH |
159 | /** |
160 | * css_for_each_descendant_pre - pre-order walk of a css's descendants | |
161 | * @pos: the css * to use as the loop cursor | |
162 | * @root: css whose descendants to walk | |
163 | * | |
164 | * Walk @root's descendants. @root is included in the iteration and the | |
165 | * first node to be visited. Must be called under rcu_read_lock(). | |
166 | * | |
167 | * If a subsystem synchronizes ->css_online() and the start of iteration, a | |
168 | * css which finished ->css_online() is guaranteed to be visible in the | |
169 | * future iterations and will stay visible until the last reference is put. | |
170 | * A css which hasn't finished ->css_online() or already finished | |
171 | * ->css_offline() may show up during traversal. It's each subsystem's | |
172 | * responsibility to synchronize against on/offlining. | |
173 | * | |
174 | * For example, the following guarantees that a descendant can't escape | |
175 | * state updates of its ancestors. | |
176 | * | |
177 | * my_online(@css) | |
178 | * { | |
179 | * Lock @css's parent and @css; | |
180 | * Inherit state from the parent; | |
181 | * Unlock both. | |
182 | * } | |
183 | * | |
184 | * my_update_state(@css) | |
185 | * { | |
186 | * css_for_each_descendant_pre(@pos, @css) { | |
187 | * Lock @pos; | |
188 | * if (@pos == @css) | |
189 | * Update @css's state; | |
190 | * else | |
191 | * Verify @pos is alive and inherit state from its parent; | |
192 | * Unlock @pos; | |
193 | * } | |
194 | * } | |
195 | * | |
196 | * As long as the inheriting step, including checking the parent state, is | |
197 | * enclosed inside @pos locking, double-locking the parent isn't necessary | |
198 | * while inheriting. The state update to the parent is guaranteed to be | |
199 | * visible by walking order and, as long as inheriting operations to the | |
200 | * same @pos are atomic to each other, multiple updates racing each other | |
201 | * still result in the correct state. It's guaranateed that at least one | |
202 | * inheritance happens for any css after the latest update to its parent. | |
203 | * | |
204 | * If checking parent's state requires locking the parent, each inheriting | |
205 | * iteration should lock and unlock both @pos->parent and @pos. | |
206 | * | |
207 | * Alternatively, a subsystem may choose to use a single global lock to | |
208 | * synchronize ->css_online() and ->css_offline() against tree-walking | |
209 | * operations. | |
210 | * | |
211 | * It is allowed to temporarily drop RCU read lock during iteration. The | |
212 | * caller is responsible for ensuring that @pos remains accessible until | |
213 | * the start of the next iteration by, for example, bumping the css refcnt. | |
214 | */ | |
215 | #define css_for_each_descendant_pre(pos, css) \ | |
216 | for ((pos) = css_next_descendant_pre(NULL, (css)); (pos); \ | |
217 | (pos) = css_next_descendant_pre((pos), (css))) | |
218 | ||
219 | /** | |
220 | * css_for_each_descendant_post - post-order walk of a css's descendants | |
221 | * @pos: the css * to use as the loop cursor | |
222 | * @css: css whose descendants to walk | |
223 | * | |
224 | * Similar to css_for_each_descendant_pre() but performs post-order | |
225 | * traversal instead. @root is included in the iteration and the last | |
226 | * node to be visited. | |
227 | * | |
228 | * If a subsystem synchronizes ->css_online() and the start of iteration, a | |
229 | * css which finished ->css_online() is guaranteed to be visible in the | |
230 | * future iterations and will stay visible until the last reference is put. | |
231 | * A css which hasn't finished ->css_online() or already finished | |
232 | * ->css_offline() may show up during traversal. It's each subsystem's | |
233 | * responsibility to synchronize against on/offlining. | |
234 | * | |
235 | * Note that the walk visibility guarantee example described in pre-order | |
236 | * walk doesn't apply the same to post-order walks. | |
237 | */ | |
238 | #define css_for_each_descendant_post(pos, css) \ | |
239 | for ((pos) = css_next_descendant_post(NULL, (css)); (pos); \ | |
240 | (pos) = css_next_descendant_post((pos), (css))) | |
241 | ||
242 | /** | |
243 | * cgroup_taskset_for_each - iterate cgroup_taskset | |
244 | * @task: the loop cursor | |
1f7dd3e5 | 245 | * @dst_css: the destination css |
c326aa2b | 246 | * @tset: taskset to iterate |
4530eddb TH |
247 | * |
248 | * @tset may contain multiple tasks and they may belong to multiple | |
1f7dd3e5 TH |
249 | * processes. |
250 | * | |
251 | * On the v2 hierarchy, there may be tasks from multiple processes and they | |
252 | * may not share the source or destination csses. | |
253 | * | |
254 | * On traditional hierarchies, when there are multiple tasks in @tset, if a | |
255 | * task of a process is in @tset, all tasks of the process are in @tset. | |
256 | * Also, all are guaranteed to share the same source and destination csses. | |
4530eddb TH |
257 | * |
258 | * Iteration is not in any specific order. | |
c326aa2b | 259 | */ |
1f7dd3e5 TH |
260 | #define cgroup_taskset_for_each(task, dst_css, tset) \ |
261 | for ((task) = cgroup_taskset_first((tset), &(dst_css)); \ | |
262 | (task); \ | |
263 | (task) = cgroup_taskset_next((tset), &(dst_css))) | |
ddbcc7e8 | 264 | |
4530eddb TH |
265 | /** |
266 | * cgroup_taskset_for_each_leader - iterate group leaders in a cgroup_taskset | |
267 | * @leader: the loop cursor | |
1f7dd3e5 | 268 | * @dst_css: the destination css |
4530eddb TH |
269 | * @tset: takset to iterate |
270 | * | |
271 | * Iterate threadgroup leaders of @tset. For single-task migrations, @tset | |
272 | * may not contain any. | |
273 | */ | |
1f7dd3e5 TH |
274 | #define cgroup_taskset_for_each_leader(leader, dst_css, tset) \ |
275 | for ((leader) = cgroup_taskset_first((tset), &(dst_css)); \ | |
276 | (leader); \ | |
277 | (leader) = cgroup_taskset_next((tset), &(dst_css))) \ | |
4530eddb TH |
278 | if ((leader) != (leader)->group_leader) \ |
279 | ; \ | |
280 | else | |
281 | ||
c326aa2b TH |
282 | /* |
283 | * Inline functions. | |
284 | */ | |
ddbcc7e8 | 285 | |
5de0107e TH |
286 | /** |
287 | * css_get - obtain a reference on the specified css | |
288 | * @css: target css | |
289 | * | |
290 | * The caller must already have a reference. | |
ddbcc7e8 | 291 | */ |
ddbcc7e8 PM |
292 | static inline void css_get(struct cgroup_subsys_state *css) |
293 | { | |
3b514d24 TH |
294 | if (!(css->flags & CSS_NO_REF)) |
295 | percpu_ref_get(&css->refcnt); | |
ddbcc7e8 | 296 | } |
e7c5ec91 | 297 | |
e8ea14cc JW |
298 | /** |
299 | * css_get_many - obtain references on the specified css | |
300 | * @css: target css | |
301 | * @n: number of references to get | |
302 | * | |
303 | * The caller must already have a reference. | |
304 | */ | |
305 | static inline void css_get_many(struct cgroup_subsys_state *css, unsigned int n) | |
306 | { | |
307 | if (!(css->flags & CSS_NO_REF)) | |
308 | percpu_ref_get_many(&css->refcnt, n); | |
309 | } | |
310 | ||
6f4524d3 TH |
311 | /** |
312 | * css_tryget - try to obtain a reference on the specified css | |
313 | * @css: target css | |
314 | * | |
315 | * Obtain a reference on @css unless it already has reached zero and is | |
316 | * being released. This function doesn't care whether @css is on or | |
317 | * offline. The caller naturally needs to ensure that @css is accessible | |
318 | * but doesn't have to be holding a reference on it - IOW, RCU protected | |
319 | * access is good enough for this function. Returns %true if a reference | |
320 | * count was successfully obtained; %false otherwise. | |
321 | */ | |
322 | static inline bool css_tryget(struct cgroup_subsys_state *css) | |
323 | { | |
324 | if (!(css->flags & CSS_NO_REF)) | |
325 | return percpu_ref_tryget(&css->refcnt); | |
326 | return true; | |
327 | } | |
328 | ||
5de0107e | 329 | /** |
ec903c0c | 330 | * css_tryget_online - try to obtain a reference on the specified css if online |
5de0107e TH |
331 | * @css: target css |
332 | * | |
ec903c0c TH |
333 | * Obtain a reference on @css if it's online. The caller naturally needs |
334 | * to ensure that @css is accessible but doesn't have to be holding a | |
5de0107e TH |
335 | * reference on it - IOW, RCU protected access is good enough for this |
336 | * function. Returns %true if a reference count was successfully obtained; | |
337 | * %false otherwise. | |
338 | */ | |
ec903c0c | 339 | static inline bool css_tryget_online(struct cgroup_subsys_state *css) |
e7c5ec91 | 340 | { |
3b514d24 TH |
341 | if (!(css->flags & CSS_NO_REF)) |
342 | return percpu_ref_tryget_live(&css->refcnt); | |
343 | return true; | |
e7c5ec91 | 344 | } |
2f7ee569 TH |
345 | |
346 | /** | |
5de0107e TH |
347 | * css_put - put a css reference |
348 | * @css: target css | |
349 | * | |
ec903c0c | 350 | * Put a reference obtained via css_get() and css_tryget_online(). |
2f7ee569 | 351 | */ |
ddbcc7e8 PM |
352 | static inline void css_put(struct cgroup_subsys_state *css) |
353 | { | |
3b514d24 TH |
354 | if (!(css->flags & CSS_NO_REF)) |
355 | percpu_ref_put(&css->refcnt); | |
ddbcc7e8 | 356 | } |
2f7ee569 | 357 | |
e8ea14cc JW |
358 | /** |
359 | * css_put_many - put css references | |
360 | * @css: target css | |
361 | * @n: number of references to put | |
362 | * | |
363 | * Put references obtained via css_get() and css_tryget_online(). | |
21acb9ca | 364 | */ |
e8ea14cc JW |
365 | static inline void css_put_many(struct cgroup_subsys_state *css, unsigned int n) |
366 | { | |
367 | if (!(css->flags & CSS_NO_REF)) | |
368 | percpu_ref_put_many(&css->refcnt, n); | |
369 | } | |
ddbcc7e8 | 370 | |
16af4396 TH |
371 | static inline void cgroup_put(struct cgroup *cgrp) |
372 | { | |
373 | css_put(&cgrp->self); | |
374 | } | |
375 | ||
14611e51 TH |
376 | /** |
377 | * task_css_set_check - obtain a task's css_set with extra access conditions | |
378 | * @task: the task to obtain css_set for | |
379 | * @__c: extra condition expression to be passed to rcu_dereference_check() | |
380 | * | |
381 | * A task's css_set is RCU protected, initialized and exited while holding | |
382 | * task_lock(), and can only be modified while holding both cgroup_mutex | |
383 | * and task_lock() while the task is alive. This macro verifies that the | |
384 | * caller is inside proper critical section and returns @task's css_set. | |
385 | * | |
386 | * The caller can also specify additional allowed conditions via @__c, such | |
387 | * as locks used during the cgroup_subsys::attach() methods. | |
dc61b1d6 | 388 | */ |
2219449a TH |
389 | #ifdef CONFIG_PROVE_RCU |
390 | extern struct mutex cgroup_mutex; | |
f0d9a5f1 | 391 | extern spinlock_t css_set_lock; |
14611e51 TH |
392 | #define task_css_set_check(task, __c) \ |
393 | rcu_dereference_check((task)->cgroups, \ | |
0e1d768f | 394 | lockdep_is_held(&cgroup_mutex) || \ |
f0d9a5f1 | 395 | lockdep_is_held(&css_set_lock) || \ |
0e1d768f | 396 | ((task)->flags & PF_EXITING) || (__c)) |
2219449a | 397 | #else |
14611e51 TH |
398 | #define task_css_set_check(task, __c) \ |
399 | rcu_dereference((task)->cgroups) | |
2219449a | 400 | #endif |
dc61b1d6 | 401 | |
14611e51 | 402 | /** |
8af01f56 | 403 | * task_css_check - obtain css for (task, subsys) w/ extra access conds |
14611e51 TH |
404 | * @task: the target task |
405 | * @subsys_id: the target subsystem ID | |
406 | * @__c: extra condition expression to be passed to rcu_dereference_check() | |
407 | * | |
408 | * Return the cgroup_subsys_state for the (@task, @subsys_id) pair. The | |
409 | * synchronization rules are the same as task_css_set_check(). | |
410 | */ | |
8af01f56 | 411 | #define task_css_check(task, subsys_id, __c) \ |
14611e51 TH |
412 | task_css_set_check((task), (__c))->subsys[(subsys_id)] |
413 | ||
414 | /** | |
415 | * task_css_set - obtain a task's css_set | |
416 | * @task: the task to obtain css_set for | |
417 | * | |
418 | * See task_css_set_check(). | |
419 | */ | |
420 | static inline struct css_set *task_css_set(struct task_struct *task) | |
421 | { | |
422 | return task_css_set_check(task, false); | |
423 | } | |
424 | ||
425 | /** | |
8af01f56 | 426 | * task_css - obtain css for (task, subsys) |
14611e51 TH |
427 | * @task: the target task |
428 | * @subsys_id: the target subsystem ID | |
429 | * | |
8af01f56 | 430 | * See task_css_check(). |
14611e51 | 431 | */ |
8af01f56 TH |
432 | static inline struct cgroup_subsys_state *task_css(struct task_struct *task, |
433 | int subsys_id) | |
ddbcc7e8 | 434 | { |
8af01f56 | 435 | return task_css_check(task, subsys_id, false); |
ddbcc7e8 PM |
436 | } |
437 | ||
ec438699 TH |
438 | /** |
439 | * task_get_css - find and get the css for (task, subsys) | |
440 | * @task: the target task | |
441 | * @subsys_id: the target subsystem ID | |
442 | * | |
443 | * Find the css for the (@task, @subsys_id) combination, increment a | |
444 | * reference on and return it. This function is guaranteed to return a | |
445 | * valid css. | |
446 | */ | |
447 | static inline struct cgroup_subsys_state * | |
448 | task_get_css(struct task_struct *task, int subsys_id) | |
449 | { | |
450 | struct cgroup_subsys_state *css; | |
451 | ||
452 | rcu_read_lock(); | |
453 | while (true) { | |
454 | css = task_css(task, subsys_id); | |
455 | if (likely(css_tryget_online(css))) | |
456 | break; | |
457 | cpu_relax(); | |
458 | } | |
459 | rcu_read_unlock(); | |
460 | return css; | |
461 | } | |
462 | ||
5024ae29 TH |
463 | /** |
464 | * task_css_is_root - test whether a task belongs to the root css | |
465 | * @task: the target task | |
466 | * @subsys_id: the target subsystem ID | |
467 | * | |
468 | * Test whether @task belongs to the root css on the specified subsystem. | |
469 | * May be invoked in any context. | |
470 | */ | |
471 | static inline bool task_css_is_root(struct task_struct *task, int subsys_id) | |
472 | { | |
473 | return task_css_check(task, subsys_id, true) == | |
474 | init_css_set.subsys[subsys_id]; | |
475 | } | |
476 | ||
8af01f56 TH |
477 | static inline struct cgroup *task_cgroup(struct task_struct *task, |
478 | int subsys_id) | |
ddbcc7e8 | 479 | { |
8af01f56 | 480 | return task_css(task, subsys_id)->cgroup; |
ddbcc7e8 PM |
481 | } |
482 | ||
b11cfb58 TH |
483 | /** |
484 | * cgroup_is_descendant - test ancestry | |
485 | * @cgrp: the cgroup to be tested | |
486 | * @ancestor: possible ancestor of @cgrp | |
487 | * | |
488 | * Test whether @cgrp is a descendant of @ancestor. It also returns %true | |
489 | * if @cgrp == @ancestor. This function is safe to call as long as @cgrp | |
490 | * and @ancestor are accessible. | |
491 | */ | |
492 | static inline bool cgroup_is_descendant(struct cgroup *cgrp, | |
493 | struct cgroup *ancestor) | |
494 | { | |
495 | if (cgrp->root != ancestor->root || cgrp->level < ancestor->level) | |
496 | return false; | |
497 | return cgrp->ancestor_ids[ancestor->level] == ancestor->id; | |
498 | } | |
499 | ||
aed704b7 SD |
500 | /** |
501 | * task_under_cgroup_hierarchy - test task's membership of cgroup ancestry | |
502 | * @task: the task to be tested | |
503 | * @ancestor: possible ancestor of @task's cgroup | |
504 | * | |
505 | * Tests whether @task's default cgroup hierarchy is a descendant of @ancestor. | |
506 | * It follows all the same rules as cgroup_is_descendant, and only applies | |
507 | * to the default hierarchy. | |
508 | */ | |
509 | static inline bool task_under_cgroup_hierarchy(struct task_struct *task, | |
510 | struct cgroup *ancestor) | |
511 | { | |
512 | struct css_set *cset = task_css_set(task); | |
513 | ||
514 | return cgroup_is_descendant(cset->dfl_cgrp, ancestor); | |
515 | } | |
516 | ||
07bc356e | 517 | /* no synchronization, the result can only be used as a hint */ |
27bd4dbb | 518 | static inline bool cgroup_is_populated(struct cgroup *cgrp) |
07bc356e | 519 | { |
27bd4dbb | 520 | return cgrp->populated_cnt; |
07bc356e | 521 | } |
f3d46500 | 522 | |
f29374b1 | 523 | /* returns ino associated with a cgroup */ |
b1664924 TH |
524 | static inline ino_t cgroup_ino(struct cgroup *cgrp) |
525 | { | |
f29374b1 | 526 | return cgrp->kn->ino; |
b1664924 | 527 | } |
3ebb2b6e | 528 | |
b4168640 TH |
529 | /* cft/css accessors for cftype->write() operation */ |
530 | static inline struct cftype *of_cft(struct kernfs_open_file *of) | |
7da11279 | 531 | { |
2bd59d48 | 532 | return of->kn->priv; |
7da11279 | 533 | } |
0f0a2b4f | 534 | |
b4168640 | 535 | struct cgroup_subsys_state *of_css(struct kernfs_open_file *of); |
817929ec | 536 | |
b4168640 TH |
537 | /* cft/css accessors for cftype->seq_*() operations */ |
538 | static inline struct cftype *seq_cft(struct seq_file *seq) | |
539 | { | |
540 | return of_cft(seq->private); | |
541 | } | |
e535837b | 542 | |
b4168640 TH |
543 | static inline struct cgroup_subsys_state *seq_css(struct seq_file *seq) |
544 | { | |
545 | return of_css(seq->private); | |
546 | } | |
31583bb0 | 547 | |
e61734c5 TH |
548 | /* |
549 | * Name / path handling functions. All are thin wrappers around the kernfs | |
550 | * counterparts and can be called under any context. | |
551 | */ | |
38460b48 | 552 | |
e61734c5 TH |
553 | static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen) |
554 | { | |
fdce6bf8 | 555 | return kernfs_name(cgrp->kn, buf, buflen); |
e61734c5 | 556 | } |
ddbcc7e8 | 557 | |
e61734c5 TH |
558 | static inline char * __must_check cgroup_path(struct cgroup *cgrp, char *buf, |
559 | size_t buflen) | |
560 | { | |
fdce6bf8 | 561 | return kernfs_path(cgrp->kn, buf, buflen); |
e61734c5 | 562 | } |
f3ba5380 | 563 | |
e61734c5 TH |
564 | static inline void pr_cont_cgroup_name(struct cgroup *cgrp) |
565 | { | |
fdce6bf8 | 566 | pr_cont_kernfs_name(cgrp->kn); |
e61734c5 | 567 | } |
ddbcc7e8 | 568 | |
e61734c5 | 569 | static inline void pr_cont_cgroup_path(struct cgroup *cgrp) |
846c7bb0 | 570 | { |
fdce6bf8 | 571 | pr_cont_kernfs_path(cgrp->kn); |
846c7bb0 | 572 | } |
ddbcc7e8 | 573 | |
ddbcc7e8 PM |
574 | #else /* !CONFIG_CGROUPS */ |
575 | ||
f3ba5380 | 576 | struct cgroup_subsys_state; |
aed704b7 | 577 | struct cgroup; |
f3ba5380 | 578 | |
c326aa2b | 579 | static inline void css_put(struct cgroup_subsys_state *css) {} |
31583bb0 | 580 | static inline int cgroup_attach_task_all(struct task_struct *from, |
c326aa2b TH |
581 | struct task_struct *t) { return 0; } |
582 | static inline int cgroupstats_build(struct cgroupstats *stats, | |
583 | struct dentry *dentry) { return -EINVAL; } | |
584 | ||
b4f48b63 | 585 | static inline void cgroup_fork(struct task_struct *p) {} |
b53202e6 ON |
586 | static inline int cgroup_can_fork(struct task_struct *p) { return 0; } |
587 | static inline void cgroup_cancel_fork(struct task_struct *p) {} | |
588 | static inline void cgroup_post_fork(struct task_struct *p) {} | |
1ec41830 | 589 | static inline void cgroup_exit(struct task_struct *p) {} |
2e91fa7f | 590 | static inline void cgroup_free(struct task_struct *p) {} |
ddbcc7e8 | 591 | |
c326aa2b TH |
592 | static inline int cgroup_init_early(void) { return 0; } |
593 | static inline int cgroup_init(void) { return 0; } | |
d7926ee3 | 594 | |
aed704b7 SD |
595 | static inline bool task_under_cgroup_hierarchy(struct task_struct *task, |
596 | struct cgroup *ancestor) | |
597 | { | |
598 | return true; | |
599 | } | |
ddbcc7e8 PM |
600 | #endif /* !CONFIG_CGROUPS */ |
601 | ||
bd1060a1 TH |
602 | /* |
603 | * sock->sk_cgrp_data handling. For more info, see sock_cgroup_data | |
604 | * definition in cgroup-defs.h. | |
605 | */ | |
606 | #ifdef CONFIG_SOCK_CGROUP_DATA | |
607 | ||
608 | #if defined(CONFIG_CGROUP_NET_PRIO) || defined(CONFIG_CGROUP_NET_CLASSID) | |
609 | extern spinlock_t cgroup_sk_update_lock; | |
610 | #endif | |
611 | ||
612 | void cgroup_sk_alloc_disable(void); | |
613 | void cgroup_sk_alloc(struct sock_cgroup_data *skcd); | |
614 | void cgroup_sk_free(struct sock_cgroup_data *skcd); | |
615 | ||
616 | static inline struct cgroup *sock_cgroup_ptr(struct sock_cgroup_data *skcd) | |
617 | { | |
618 | #if defined(CONFIG_CGROUP_NET_PRIO) || defined(CONFIG_CGROUP_NET_CLASSID) | |
619 | unsigned long v; | |
620 | ||
621 | /* | |
622 | * @skcd->val is 64bit but the following is safe on 32bit too as we | |
623 | * just need the lower ulong to be written and read atomically. | |
624 | */ | |
625 | v = READ_ONCE(skcd->val); | |
626 | ||
627 | if (v & 1) | |
628 | return &cgrp_dfl_root.cgrp; | |
629 | ||
630 | return (struct cgroup *)(unsigned long)v ?: &cgrp_dfl_root.cgrp; | |
631 | #else | |
632 | return (struct cgroup *)(unsigned long)skcd->val; | |
633 | #endif | |
634 | } | |
635 | ||
636 | #else /* CONFIG_CGROUP_DATA */ | |
637 | ||
638 | static inline void cgroup_sk_alloc(struct sock_cgroup_data *skcd) {} | |
639 | static inline void cgroup_sk_free(struct sock_cgroup_data *skcd) {} | |
640 | ||
641 | #endif /* CONFIG_CGROUP_DATA */ | |
642 | ||
a79a908f AK |
643 | struct cgroup_namespace { |
644 | atomic_t count; | |
645 | struct ns_common ns; | |
646 | struct user_namespace *user_ns; | |
d08311dd | 647 | struct ucounts *ucounts; |
a79a908f AK |
648 | struct css_set *root_cset; |
649 | }; | |
650 | ||
651 | extern struct cgroup_namespace init_cgroup_ns; | |
652 | ||
653 | #ifdef CONFIG_CGROUPS | |
654 | ||
655 | void free_cgroup_ns(struct cgroup_namespace *ns); | |
656 | ||
657 | struct cgroup_namespace *copy_cgroup_ns(unsigned long flags, | |
658 | struct user_namespace *user_ns, | |
659 | struct cgroup_namespace *old_ns); | |
660 | ||
661 | char *cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen, | |
662 | struct cgroup_namespace *ns); | |
663 | ||
664 | #else /* !CONFIG_CGROUPS */ | |
665 | ||
666 | static inline void free_cgroup_ns(struct cgroup_namespace *ns) { } | |
667 | static inline struct cgroup_namespace * | |
668 | copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns, | |
669 | struct cgroup_namespace *old_ns) | |
670 | { | |
671 | return old_ns; | |
672 | } | |
673 | ||
674 | #endif /* !CONFIG_CGROUPS */ | |
675 | ||
676 | static inline void get_cgroup_ns(struct cgroup_namespace *ns) | |
677 | { | |
678 | if (ns) | |
679 | atomic_inc(&ns->count); | |
680 | } | |
681 | ||
682 | static inline void put_cgroup_ns(struct cgroup_namespace *ns) | |
683 | { | |
684 | if (ns && atomic_dec_and_test(&ns->count)) | |
685 | free_cgroup_ns(ns); | |
686 | } | |
687 | ||
ddbcc7e8 | 688 | #endif /* _LINUX_CGROUP_H */ |