]>
Commit | Line | Data |
---|---|---|
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/types.h> |
21 | #include <linux/ns_common.h> | |
22 | #include <linux/nsproxy.h> | |
23 | #include <linux/user_namespace.h> | |
387ad967 | 24 | #include <linux/refcount.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 | ||
bc2fb7ed TH |
39 | /* walk only threadgroup leaders */ |
40 | #define CSS_TASK_ITER_PROCS (1U << 0) | |
41 | ||
c326aa2b TH |
42 | /* a css_task_iter should be treated as an opaque object */ |
43 | struct css_task_iter { | |
44 | struct cgroup_subsys *ss; | |
bc2fb7ed | 45 | unsigned int flags; |
c326aa2b TH |
46 | |
47 | struct list_head *cset_pos; | |
48 | struct list_head *cset_head; | |
ddbcc7e8 | 49 | |
c326aa2b TH |
50 | struct list_head *task_pos; |
51 | struct list_head *tasks_head; | |
52 | struct list_head *mg_tasks_head; | |
ed27b9f7 TH |
53 | |
54 | struct css_set *cur_cset; | |
55 | struct task_struct *cur_task; | |
56 | struct list_head iters_node; /* css_set->task_iters */ | |
c326aa2b | 57 | }; |
ddbcc7e8 | 58 | |
c326aa2b TH |
59 | extern struct cgroup_root cgrp_dfl_root; |
60 | extern struct css_set init_css_set; | |
a424316c | 61 | |
c326aa2b | 62 | #define SUBSYS(_x) extern struct cgroup_subsys _x ## _cgrp_subsys; |
817929ec | 63 | #include <linux/cgroup_subsys.h> |
817929ec PM |
64 | #undef SUBSYS |
65 | ||
49d1dc4b TH |
66 | #define SUBSYS(_x) \ |
67 | extern struct static_key_true _x ## _cgrp_subsys_enabled_key; \ | |
68 | extern struct static_key_true _x ## _cgrp_subsys_on_dfl_key; | |
69 | #include <linux/cgroup_subsys.h> | |
70 | #undef SUBSYS | |
71 | ||
72 | /** | |
73 | * cgroup_subsys_enabled - fast test on whether a subsys is enabled | |
74 | * @ss: subsystem in question | |
75 | */ | |
76 | #define cgroup_subsys_enabled(ss) \ | |
77 | static_branch_likely(&ss ## _enabled_key) | |
78 | ||
79 | /** | |
80 | * cgroup_subsys_on_dfl - fast test on whether a subsys is on default hierarchy | |
81 | * @ss: subsystem in question | |
82 | */ | |
83 | #define cgroup_subsys_on_dfl(ss) \ | |
84 | static_branch_likely(&ss ## _on_dfl_key) | |
85 | ||
c326aa2b TH |
86 | bool css_has_online_children(struct cgroup_subsys_state *css); |
87 | struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss); | |
88 | struct cgroup_subsys_state *cgroup_get_e_css(struct cgroup *cgroup, | |
89 | struct cgroup_subsys *ss); | |
90 | struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry, | |
91 | struct cgroup_subsys *ss); | |
92 | ||
16af4396 | 93 | struct cgroup *cgroup_get_from_path(const char *path); |
1f3fe7eb | 94 | struct cgroup *cgroup_get_from_fd(int fd); |
16af4396 | 95 | |
c326aa2b TH |
96 | int cgroup_attach_task_all(struct task_struct *from, struct task_struct *); |
97 | int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from); | |
98 | ||
99 | int cgroup_add_dfl_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); | |
100 | int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts); | |
101 | int cgroup_rm_cftypes(struct cftype *cfts); | |
34c06254 | 102 | void cgroup_file_notify(struct cgroup_file *cfile); |
c326aa2b | 103 | |
4c737b41 | 104 | int task_cgroup_path(struct task_struct *task, char *buf, size_t buflen); |
c326aa2b TH |
105 | int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry); |
106 | int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns, | |
107 | struct pid *pid, struct task_struct *tsk); | |
108 | ||
109 | void cgroup_fork(struct task_struct *p); | |
b53202e6 ON |
110 | extern int cgroup_can_fork(struct task_struct *p); |
111 | extern void cgroup_cancel_fork(struct task_struct *p); | |
112 | extern void cgroup_post_fork(struct task_struct *p); | |
c326aa2b | 113 | void cgroup_exit(struct task_struct *p); |
2e91fa7f | 114 | void cgroup_free(struct task_struct *p); |
c326aa2b TH |
115 | |
116 | int cgroup_init_early(void); | |
117 | int cgroup_init(void); | |
118 | ||
5c9d535b | 119 | /* |
c326aa2b TH |
120 | * Iteration helpers and macros. |
121 | */ | |
122 | ||
123 | struct cgroup_subsys_state *css_next_child(struct cgroup_subsys_state *pos, | |
124 | struct cgroup_subsys_state *parent); | |
125 | struct cgroup_subsys_state *css_next_descendant_pre(struct cgroup_subsys_state *pos, | |
126 | struct cgroup_subsys_state *css); | |
127 | struct cgroup_subsys_state *css_rightmost_descendant(struct cgroup_subsys_state *pos); | |
128 | struct cgroup_subsys_state *css_next_descendant_post(struct cgroup_subsys_state *pos, | |
129 | struct cgroup_subsys_state *css); | |
130 | ||
1f7dd3e5 TH |
131 | struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset, |
132 | struct cgroup_subsys_state **dst_cssp); | |
133 | struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset, | |
134 | struct cgroup_subsys_state **dst_cssp); | |
c326aa2b | 135 | |
bc2fb7ed | 136 | void css_task_iter_start(struct cgroup_subsys_state *css, unsigned int flags, |
c326aa2b TH |
137 | struct css_task_iter *it); |
138 | struct task_struct *css_task_iter_next(struct css_task_iter *it); | |
139 | void css_task_iter_end(struct css_task_iter *it); | |
140 | ||
141 | /** | |
142 | * css_for_each_child - iterate through children of a css | |
143 | * @pos: the css * to use as the loop cursor | |
144 | * @parent: css whose children to walk | |
145 | * | |
146 | * Walk @parent's children. Must be called under rcu_read_lock(). | |
147 | * | |
148 | * If a subsystem synchronizes ->css_online() and the start of iteration, a | |
149 | * css which finished ->css_online() is guaranteed to be visible in the | |
150 | * future iterations and will stay visible until the last reference is put. | |
151 | * A css which hasn't finished ->css_online() or already finished | |
152 | * ->css_offline() may show up during traversal. It's each subsystem's | |
153 | * responsibility to synchronize against on/offlining. | |
5c9d535b | 154 | * |
c326aa2b TH |
155 | * It is allowed to temporarily drop RCU read lock during iteration. The |
156 | * caller is responsible for ensuring that @pos remains accessible until | |
157 | * the start of the next iteration by, for example, bumping the css refcnt. | |
5c9d535b | 158 | */ |
c326aa2b TH |
159 | #define css_for_each_child(pos, parent) \ |
160 | for ((pos) = css_next_child(NULL, (parent)); (pos); \ | |
161 | (pos) = css_next_child((pos), (parent))) | |
ddbcc7e8 | 162 | |
c326aa2b TH |
163 | /** |
164 | * css_for_each_descendant_pre - pre-order walk of a css's descendants | |
165 | * @pos: the css * to use as the loop cursor | |
166 | * @root: css whose descendants to walk | |
167 | * | |
168 | * Walk @root's descendants. @root is included in the iteration and the | |
169 | * first node to be visited. Must be called under rcu_read_lock(). | |
170 | * | |
171 | * If a subsystem synchronizes ->css_online() and the start of iteration, a | |
172 | * css which finished ->css_online() is guaranteed to be visible in the | |
173 | * future iterations and will stay visible until the last reference is put. | |
174 | * A css which hasn't finished ->css_online() or already finished | |
175 | * ->css_offline() may show up during traversal. It's each subsystem's | |
176 | * responsibility to synchronize against on/offlining. | |
177 | * | |
178 | * For example, the following guarantees that a descendant can't escape | |
179 | * state updates of its ancestors. | |
180 | * | |
181 | * my_online(@css) | |
182 | * { | |
183 | * Lock @css's parent and @css; | |
184 | * Inherit state from the parent; | |
185 | * Unlock both. | |
186 | * } | |
187 | * | |
188 | * my_update_state(@css) | |
189 | * { | |
190 | * css_for_each_descendant_pre(@pos, @css) { | |
191 | * Lock @pos; | |
192 | * if (@pos == @css) | |
193 | * Update @css's state; | |
194 | * else | |
195 | * Verify @pos is alive and inherit state from its parent; | |
196 | * Unlock @pos; | |
197 | * } | |
198 | * } | |
199 | * | |
200 | * As long as the inheriting step, including checking the parent state, is | |
201 | * enclosed inside @pos locking, double-locking the parent isn't necessary | |
202 | * while inheriting. The state update to the parent is guaranteed to be | |
203 | * visible by walking order and, as long as inheriting operations to the | |
204 | * same @pos are atomic to each other, multiple updates racing each other | |
205 | * still result in the correct state. It's guaranateed that at least one | |
206 | * inheritance happens for any css after the latest update to its parent. | |
207 | * | |
208 | * If checking parent's state requires locking the parent, each inheriting | |
209 | * iteration should lock and unlock both @pos->parent and @pos. | |
210 | * | |
211 | * Alternatively, a subsystem may choose to use a single global lock to | |
212 | * synchronize ->css_online() and ->css_offline() against tree-walking | |
213 | * operations. | |
214 | * | |
215 | * It is allowed to temporarily drop RCU read lock during iteration. The | |
216 | * caller is responsible for ensuring that @pos remains accessible until | |
217 | * the start of the next iteration by, for example, bumping the css refcnt. | |
218 | */ | |
219 | #define css_for_each_descendant_pre(pos, css) \ | |
220 | for ((pos) = css_next_descendant_pre(NULL, (css)); (pos); \ | |
221 | (pos) = css_next_descendant_pre((pos), (css))) | |
222 | ||
223 | /** | |
224 | * css_for_each_descendant_post - post-order walk of a css's descendants | |
225 | * @pos: the css * to use as the loop cursor | |
226 | * @css: css whose descendants to walk | |
227 | * | |
228 | * Similar to css_for_each_descendant_pre() but performs post-order | |
229 | * traversal instead. @root is included in the iteration and the last | |
230 | * node to be visited. | |
231 | * | |
232 | * If a subsystem synchronizes ->css_online() and the start of iteration, a | |
233 | * css which finished ->css_online() is guaranteed to be visible in the | |
234 | * future iterations and will stay visible until the last reference is put. | |
235 | * A css which hasn't finished ->css_online() or already finished | |
236 | * ->css_offline() may show up during traversal. It's each subsystem's | |
237 | * responsibility to synchronize against on/offlining. | |
238 | * | |
239 | * Note that the walk visibility guarantee example described in pre-order | |
240 | * walk doesn't apply the same to post-order walks. | |
241 | */ | |
242 | #define css_for_each_descendant_post(pos, css) \ | |
243 | for ((pos) = css_next_descendant_post(NULL, (css)); (pos); \ | |
244 | (pos) = css_next_descendant_post((pos), (css))) | |
245 | ||
246 | /** | |
247 | * cgroup_taskset_for_each - iterate cgroup_taskset | |
248 | * @task: the loop cursor | |
1f7dd3e5 | 249 | * @dst_css: the destination css |
c326aa2b | 250 | * @tset: taskset to iterate |
4530eddb TH |
251 | * |
252 | * @tset may contain multiple tasks and they may belong to multiple | |
1f7dd3e5 TH |
253 | * processes. |
254 | * | |
255 | * On the v2 hierarchy, there may be tasks from multiple processes and they | |
256 | * may not share the source or destination csses. | |
257 | * | |
258 | * On traditional hierarchies, when there are multiple tasks in @tset, if a | |
259 | * task of a process is in @tset, all tasks of the process are in @tset. | |
260 | * Also, all are guaranteed to share the same source and destination csses. | |
4530eddb TH |
261 | * |
262 | * Iteration is not in any specific order. | |
c326aa2b | 263 | */ |
1f7dd3e5 TH |
264 | #define cgroup_taskset_for_each(task, dst_css, tset) \ |
265 | for ((task) = cgroup_taskset_first((tset), &(dst_css)); \ | |
266 | (task); \ | |
267 | (task) = cgroup_taskset_next((tset), &(dst_css))) | |
ddbcc7e8 | 268 | |
4530eddb TH |
269 | /** |
270 | * cgroup_taskset_for_each_leader - iterate group leaders in a cgroup_taskset | |
271 | * @leader: the loop cursor | |
1f7dd3e5 | 272 | * @dst_css: the destination css |
7b4632f0 | 273 | * @tset: taskset to iterate |
4530eddb TH |
274 | * |
275 | * Iterate threadgroup leaders of @tset. For single-task migrations, @tset | |
276 | * may not contain any. | |
277 | */ | |
1f7dd3e5 TH |
278 | #define cgroup_taskset_for_each_leader(leader, dst_css, tset) \ |
279 | for ((leader) = cgroup_taskset_first((tset), &(dst_css)); \ | |
280 | (leader); \ | |
281 | (leader) = cgroup_taskset_next((tset), &(dst_css))) \ | |
4530eddb TH |
282 | if ((leader) != (leader)->group_leader) \ |
283 | ; \ | |
284 | else | |
285 | ||
c326aa2b TH |
286 | /* |
287 | * Inline functions. | |
288 | */ | |
ddbcc7e8 | 289 | |
5de0107e TH |
290 | /** |
291 | * css_get - obtain a reference on the specified css | |
292 | * @css: target css | |
293 | * | |
294 | * The caller must already have a reference. | |
ddbcc7e8 | 295 | */ |
ddbcc7e8 PM |
296 | static inline void css_get(struct cgroup_subsys_state *css) |
297 | { | |
3b514d24 TH |
298 | if (!(css->flags & CSS_NO_REF)) |
299 | percpu_ref_get(&css->refcnt); | |
ddbcc7e8 | 300 | } |
e7c5ec91 | 301 | |
e8ea14cc JW |
302 | /** |
303 | * css_get_many - obtain references on the specified css | |
304 | * @css: target css | |
305 | * @n: number of references to get | |
306 | * | |
307 | * The caller must already have a reference. | |
308 | */ | |
309 | static inline void css_get_many(struct cgroup_subsys_state *css, unsigned int n) | |
310 | { | |
311 | if (!(css->flags & CSS_NO_REF)) | |
312 | percpu_ref_get_many(&css->refcnt, n); | |
313 | } | |
314 | ||
6f4524d3 TH |
315 | /** |
316 | * css_tryget - try to obtain a reference on the specified css | |
317 | * @css: target css | |
318 | * | |
319 | * Obtain a reference on @css unless it already has reached zero and is | |
320 | * being released. This function doesn't care whether @css is on or | |
321 | * offline. The caller naturally needs to ensure that @css is accessible | |
322 | * but doesn't have to be holding a reference on it - IOW, RCU protected | |
323 | * access is good enough for this function. Returns %true if a reference | |
324 | * count was successfully obtained; %false otherwise. | |
325 | */ | |
326 | static inline bool css_tryget(struct cgroup_subsys_state *css) | |
327 | { | |
328 | if (!(css->flags & CSS_NO_REF)) | |
329 | return percpu_ref_tryget(&css->refcnt); | |
330 | return true; | |
331 | } | |
332 | ||
5de0107e | 333 | /** |
ec903c0c | 334 | * css_tryget_online - try to obtain a reference on the specified css if online |
5de0107e TH |
335 | * @css: target css |
336 | * | |
ec903c0c TH |
337 | * Obtain a reference on @css if it's online. The caller naturally needs |
338 | * to ensure that @css is accessible but doesn't have to be holding a | |
5de0107e TH |
339 | * reference on it - IOW, RCU protected access is good enough for this |
340 | * function. Returns %true if a reference count was successfully obtained; | |
341 | * %false otherwise. | |
342 | */ | |
ec903c0c | 343 | static inline bool css_tryget_online(struct cgroup_subsys_state *css) |
e7c5ec91 | 344 | { |
3b514d24 TH |
345 | if (!(css->flags & CSS_NO_REF)) |
346 | return percpu_ref_tryget_live(&css->refcnt); | |
347 | return true; | |
e7c5ec91 | 348 | } |
2f7ee569 | 349 | |
41c25707 TH |
350 | /** |
351 | * css_is_dying - test whether the specified css is dying | |
352 | * @css: target css | |
353 | * | |
354 | * Test whether @css is in the process of offlining or already offline. In | |
355 | * most cases, ->css_online() and ->css_offline() callbacks should be | |
356 | * enough; however, the actual offline operations are RCU delayed and this | |
357 | * test returns %true also when @css is scheduled to be offlined. | |
358 | * | |
359 | * This is useful, for example, when the use case requires synchronous | |
360 | * behavior with respect to cgroup removal. cgroup removal schedules css | |
361 | * offlining but the css can seem alive while the operation is being | |
362 | * delayed. If the delay affects user visible semantics, this test can be | |
363 | * used to resolve the situation. | |
364 | */ | |
365 | static inline bool css_is_dying(struct cgroup_subsys_state *css) | |
366 | { | |
367 | return !(css->flags & CSS_NO_REF) && percpu_ref_is_dying(&css->refcnt); | |
368 | } | |
369 | ||
2f7ee569 | 370 | /** |
5de0107e TH |
371 | * css_put - put a css reference |
372 | * @css: target css | |
373 | * | |
ec903c0c | 374 | * Put a reference obtained via css_get() and css_tryget_online(). |
2f7ee569 | 375 | */ |
ddbcc7e8 PM |
376 | static inline void css_put(struct cgroup_subsys_state *css) |
377 | { | |
3b514d24 TH |
378 | if (!(css->flags & CSS_NO_REF)) |
379 | percpu_ref_put(&css->refcnt); | |
ddbcc7e8 | 380 | } |
2f7ee569 | 381 | |
e8ea14cc JW |
382 | /** |
383 | * css_put_many - put css references | |
384 | * @css: target css | |
385 | * @n: number of references to put | |
386 | * | |
387 | * Put references obtained via css_get() and css_tryget_online(). | |
21acb9ca | 388 | */ |
e8ea14cc JW |
389 | static inline void css_put_many(struct cgroup_subsys_state *css, unsigned int n) |
390 | { | |
391 | if (!(css->flags & CSS_NO_REF)) | |
392 | percpu_ref_put_many(&css->refcnt, n); | |
393 | } | |
ddbcc7e8 | 394 | |
16af4396 TH |
395 | static inline void cgroup_put(struct cgroup *cgrp) |
396 | { | |
397 | css_put(&cgrp->self); | |
398 | } | |
399 | ||
14611e51 TH |
400 | /** |
401 | * task_css_set_check - obtain a task's css_set with extra access conditions | |
402 | * @task: the task to obtain css_set for | |
403 | * @__c: extra condition expression to be passed to rcu_dereference_check() | |
404 | * | |
405 | * A task's css_set is RCU protected, initialized and exited while holding | |
406 | * task_lock(), and can only be modified while holding both cgroup_mutex | |
407 | * and task_lock() while the task is alive. This macro verifies that the | |
408 | * caller is inside proper critical section and returns @task's css_set. | |
409 | * | |
410 | * The caller can also specify additional allowed conditions via @__c, such | |
411 | * as locks used during the cgroup_subsys::attach() methods. | |
dc61b1d6 | 412 | */ |
2219449a TH |
413 | #ifdef CONFIG_PROVE_RCU |
414 | extern struct mutex cgroup_mutex; | |
f0d9a5f1 | 415 | extern spinlock_t css_set_lock; |
14611e51 TH |
416 | #define task_css_set_check(task, __c) \ |
417 | rcu_dereference_check((task)->cgroups, \ | |
0e1d768f | 418 | lockdep_is_held(&cgroup_mutex) || \ |
f0d9a5f1 | 419 | lockdep_is_held(&css_set_lock) || \ |
0e1d768f | 420 | ((task)->flags & PF_EXITING) || (__c)) |
2219449a | 421 | #else |
14611e51 TH |
422 | #define task_css_set_check(task, __c) \ |
423 | rcu_dereference((task)->cgroups) | |
2219449a | 424 | #endif |
dc61b1d6 | 425 | |
14611e51 | 426 | /** |
8af01f56 | 427 | * task_css_check - obtain css for (task, subsys) w/ extra access conds |
14611e51 TH |
428 | * @task: the target task |
429 | * @subsys_id: the target subsystem ID | |
430 | * @__c: extra condition expression to be passed to rcu_dereference_check() | |
431 | * | |
432 | * Return the cgroup_subsys_state for the (@task, @subsys_id) pair. The | |
433 | * synchronization rules are the same as task_css_set_check(). | |
434 | */ | |
8af01f56 | 435 | #define task_css_check(task, subsys_id, __c) \ |
14611e51 TH |
436 | task_css_set_check((task), (__c))->subsys[(subsys_id)] |
437 | ||
438 | /** | |
439 | * task_css_set - obtain a task's css_set | |
440 | * @task: the task to obtain css_set for | |
441 | * | |
442 | * See task_css_set_check(). | |
443 | */ | |
444 | static inline struct css_set *task_css_set(struct task_struct *task) | |
445 | { | |
446 | return task_css_set_check(task, false); | |
447 | } | |
448 | ||
449 | /** | |
8af01f56 | 450 | * task_css - obtain css for (task, subsys) |
14611e51 TH |
451 | * @task: the target task |
452 | * @subsys_id: the target subsystem ID | |
453 | * | |
8af01f56 | 454 | * See task_css_check(). |
14611e51 | 455 | */ |
8af01f56 TH |
456 | static inline struct cgroup_subsys_state *task_css(struct task_struct *task, |
457 | int subsys_id) | |
ddbcc7e8 | 458 | { |
8af01f56 | 459 | return task_css_check(task, subsys_id, false); |
ddbcc7e8 PM |
460 | } |
461 | ||
ec438699 TH |
462 | /** |
463 | * task_get_css - find and get the css for (task, subsys) | |
464 | * @task: the target task | |
465 | * @subsys_id: the target subsystem ID | |
466 | * | |
467 | * Find the css for the (@task, @subsys_id) combination, increment a | |
468 | * reference on and return it. This function is guaranteed to return a | |
469 | * valid css. | |
470 | */ | |
471 | static inline struct cgroup_subsys_state * | |
472 | task_get_css(struct task_struct *task, int subsys_id) | |
473 | { | |
474 | struct cgroup_subsys_state *css; | |
475 | ||
476 | rcu_read_lock(); | |
477 | while (true) { | |
478 | css = task_css(task, subsys_id); | |
479 | if (likely(css_tryget_online(css))) | |
480 | break; | |
481 | cpu_relax(); | |
482 | } | |
483 | rcu_read_unlock(); | |
484 | return css; | |
485 | } | |
486 | ||
5024ae29 TH |
487 | /** |
488 | * task_css_is_root - test whether a task belongs to the root css | |
489 | * @task: the target task | |
490 | * @subsys_id: the target subsystem ID | |
491 | * | |
492 | * Test whether @task belongs to the root css on the specified subsystem. | |
493 | * May be invoked in any context. | |
494 | */ | |
495 | static inline bool task_css_is_root(struct task_struct *task, int subsys_id) | |
496 | { | |
497 | return task_css_check(task, subsys_id, true) == | |
498 | init_css_set.subsys[subsys_id]; | |
499 | } | |
500 | ||
8af01f56 TH |
501 | static inline struct cgroup *task_cgroup(struct task_struct *task, |
502 | int subsys_id) | |
ddbcc7e8 | 503 | { |
8af01f56 | 504 | return task_css(task, subsys_id)->cgroup; |
ddbcc7e8 PM |
505 | } |
506 | ||
b11cfb58 TH |
507 | /** |
508 | * cgroup_is_descendant - test ancestry | |
509 | * @cgrp: the cgroup to be tested | |
510 | * @ancestor: possible ancestor of @cgrp | |
511 | * | |
512 | * Test whether @cgrp is a descendant of @ancestor. It also returns %true | |
513 | * if @cgrp == @ancestor. This function is safe to call as long as @cgrp | |
514 | * and @ancestor are accessible. | |
515 | */ | |
516 | static inline bool cgroup_is_descendant(struct cgroup *cgrp, | |
517 | struct cgroup *ancestor) | |
518 | { | |
519 | if (cgrp->root != ancestor->root || cgrp->level < ancestor->level) | |
520 | return false; | |
521 | return cgrp->ancestor_ids[ancestor->level] == ancestor->id; | |
522 | } | |
523 | ||
aed704b7 SD |
524 | /** |
525 | * task_under_cgroup_hierarchy - test task's membership of cgroup ancestry | |
526 | * @task: the task to be tested | |
527 | * @ancestor: possible ancestor of @task's cgroup | |
528 | * | |
529 | * Tests whether @task's default cgroup hierarchy is a descendant of @ancestor. | |
530 | * It follows all the same rules as cgroup_is_descendant, and only applies | |
531 | * to the default hierarchy. | |
532 | */ | |
533 | static inline bool task_under_cgroup_hierarchy(struct task_struct *task, | |
534 | struct cgroup *ancestor) | |
535 | { | |
536 | struct css_set *cset = task_css_set(task); | |
537 | ||
538 | return cgroup_is_descendant(cset->dfl_cgrp, ancestor); | |
539 | } | |
540 | ||
07bc356e | 541 | /* no synchronization, the result can only be used as a hint */ |
27bd4dbb | 542 | static inline bool cgroup_is_populated(struct cgroup *cgrp) |
07bc356e | 543 | { |
788b950c | 544 | return cgrp->nr_populated_csets + cgrp->nr_populated_children; |
07bc356e | 545 | } |
f3d46500 | 546 | |
f29374b1 | 547 | /* returns ino associated with a cgroup */ |
b1664924 TH |
548 | static inline ino_t cgroup_ino(struct cgroup *cgrp) |
549 | { | |
f29374b1 | 550 | return cgrp->kn->ino; |
b1664924 | 551 | } |
3ebb2b6e | 552 | |
b4168640 TH |
553 | /* cft/css accessors for cftype->write() operation */ |
554 | static inline struct cftype *of_cft(struct kernfs_open_file *of) | |
7da11279 | 555 | { |
2bd59d48 | 556 | return of->kn->priv; |
7da11279 | 557 | } |
0f0a2b4f | 558 | |
b4168640 | 559 | struct cgroup_subsys_state *of_css(struct kernfs_open_file *of); |
817929ec | 560 | |
b4168640 TH |
561 | /* cft/css accessors for cftype->seq_*() operations */ |
562 | static inline struct cftype *seq_cft(struct seq_file *seq) | |
563 | { | |
564 | return of_cft(seq->private); | |
565 | } | |
e535837b | 566 | |
b4168640 TH |
567 | static inline struct cgroup_subsys_state *seq_css(struct seq_file *seq) |
568 | { | |
569 | return of_css(seq->private); | |
570 | } | |
31583bb0 | 571 | |
e61734c5 TH |
572 | /* |
573 | * Name / path handling functions. All are thin wrappers around the kernfs | |
574 | * counterparts and can be called under any context. | |
575 | */ | |
38460b48 | 576 | |
e61734c5 TH |
577 | static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen) |
578 | { | |
fdce6bf8 | 579 | return kernfs_name(cgrp->kn, buf, buflen); |
e61734c5 | 580 | } |
ddbcc7e8 | 581 | |
4c737b41 | 582 | static inline int cgroup_path(struct cgroup *cgrp, char *buf, size_t buflen) |
e61734c5 | 583 | { |
fdce6bf8 | 584 | return kernfs_path(cgrp->kn, buf, buflen); |
e61734c5 | 585 | } |
f3ba5380 | 586 | |
e61734c5 TH |
587 | static inline void pr_cont_cgroup_name(struct cgroup *cgrp) |
588 | { | |
fdce6bf8 | 589 | pr_cont_kernfs_name(cgrp->kn); |
e61734c5 | 590 | } |
ddbcc7e8 | 591 | |
e61734c5 | 592 | static inline void pr_cont_cgroup_path(struct cgroup *cgrp) |
846c7bb0 | 593 | { |
fdce6bf8 | 594 | pr_cont_kernfs_path(cgrp->kn); |
846c7bb0 | 595 | } |
ddbcc7e8 | 596 | |
77f88796 TH |
597 | static inline void cgroup_init_kthreadd(void) |
598 | { | |
599 | /* | |
600 | * kthreadd is inherited by all kthreads, keep it in the root so | |
601 | * that the new kthreads are guaranteed to stay in the root until | |
602 | * initialization is finished. | |
603 | */ | |
604 | current->no_cgroup_migration = 1; | |
605 | } | |
606 | ||
607 | static inline void cgroup_kthread_ready(void) | |
608 | { | |
609 | /* | |
610 | * This kthread finished initialization. The creator should have | |
611 | * set PF_NO_SETAFFINITY if this kthread should stay in the root. | |
612 | */ | |
613 | current->no_cgroup_migration = 0; | |
614 | } | |
615 | ||
ddbcc7e8 PM |
616 | #else /* !CONFIG_CGROUPS */ |
617 | ||
f3ba5380 | 618 | struct cgroup_subsys_state; |
aed704b7 | 619 | struct cgroup; |
f3ba5380 | 620 | |
c326aa2b | 621 | static inline void css_put(struct cgroup_subsys_state *css) {} |
31583bb0 | 622 | static inline int cgroup_attach_task_all(struct task_struct *from, |
c326aa2b TH |
623 | struct task_struct *t) { return 0; } |
624 | static inline int cgroupstats_build(struct cgroupstats *stats, | |
625 | struct dentry *dentry) { return -EINVAL; } | |
626 | ||
b4f48b63 | 627 | static inline void cgroup_fork(struct task_struct *p) {} |
b53202e6 ON |
628 | static inline int cgroup_can_fork(struct task_struct *p) { return 0; } |
629 | static inline void cgroup_cancel_fork(struct task_struct *p) {} | |
630 | static inline void cgroup_post_fork(struct task_struct *p) {} | |
1ec41830 | 631 | static inline void cgroup_exit(struct task_struct *p) {} |
2e91fa7f | 632 | static inline void cgroup_free(struct task_struct *p) {} |
ddbcc7e8 | 633 | |
c326aa2b TH |
634 | static inline int cgroup_init_early(void) { return 0; } |
635 | static inline int cgroup_init(void) { return 0; } | |
77f88796 TH |
636 | static inline void cgroup_init_kthreadd(void) {} |
637 | static inline void cgroup_kthread_ready(void) {} | |
d7926ee3 | 638 | |
aed704b7 SD |
639 | static inline bool task_under_cgroup_hierarchy(struct task_struct *task, |
640 | struct cgroup *ancestor) | |
641 | { | |
642 | return true; | |
643 | } | |
ddbcc7e8 PM |
644 | #endif /* !CONFIG_CGROUPS */ |
645 | ||
bd1060a1 TH |
646 | /* |
647 | * sock->sk_cgrp_data handling. For more info, see sock_cgroup_data | |
648 | * definition in cgroup-defs.h. | |
649 | */ | |
650 | #ifdef CONFIG_SOCK_CGROUP_DATA | |
651 | ||
652 | #if defined(CONFIG_CGROUP_NET_PRIO) || defined(CONFIG_CGROUP_NET_CLASSID) | |
653 | extern spinlock_t cgroup_sk_update_lock; | |
654 | #endif | |
655 | ||
656 | void cgroup_sk_alloc_disable(void); | |
657 | void cgroup_sk_alloc(struct sock_cgroup_data *skcd); | |
658 | void cgroup_sk_free(struct sock_cgroup_data *skcd); | |
659 | ||
660 | static inline struct cgroup *sock_cgroup_ptr(struct sock_cgroup_data *skcd) | |
661 | { | |
662 | #if defined(CONFIG_CGROUP_NET_PRIO) || defined(CONFIG_CGROUP_NET_CLASSID) | |
663 | unsigned long v; | |
664 | ||
665 | /* | |
666 | * @skcd->val is 64bit but the following is safe on 32bit too as we | |
667 | * just need the lower ulong to be written and read atomically. | |
668 | */ | |
669 | v = READ_ONCE(skcd->val); | |
670 | ||
671 | if (v & 1) | |
672 | return &cgrp_dfl_root.cgrp; | |
673 | ||
674 | return (struct cgroup *)(unsigned long)v ?: &cgrp_dfl_root.cgrp; | |
675 | #else | |
676 | return (struct cgroup *)(unsigned long)skcd->val; | |
677 | #endif | |
678 | } | |
679 | ||
680 | #else /* CONFIG_CGROUP_DATA */ | |
681 | ||
682 | static inline void cgroup_sk_alloc(struct sock_cgroup_data *skcd) {} | |
683 | static inline void cgroup_sk_free(struct sock_cgroup_data *skcd) {} | |
684 | ||
685 | #endif /* CONFIG_CGROUP_DATA */ | |
686 | ||
a79a908f | 687 | struct cgroup_namespace { |
387ad967 | 688 | refcount_t count; |
a79a908f AK |
689 | struct ns_common ns; |
690 | struct user_namespace *user_ns; | |
d08311dd | 691 | struct ucounts *ucounts; |
a79a908f AK |
692 | struct css_set *root_cset; |
693 | }; | |
694 | ||
695 | extern struct cgroup_namespace init_cgroup_ns; | |
696 | ||
697 | #ifdef CONFIG_CGROUPS | |
698 | ||
699 | void free_cgroup_ns(struct cgroup_namespace *ns); | |
700 | ||
701 | struct cgroup_namespace *copy_cgroup_ns(unsigned long flags, | |
702 | struct user_namespace *user_ns, | |
703 | struct cgroup_namespace *old_ns); | |
704 | ||
4c737b41 TH |
705 | int cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen, |
706 | struct cgroup_namespace *ns); | |
a79a908f AK |
707 | |
708 | #else /* !CONFIG_CGROUPS */ | |
709 | ||
710 | static inline void free_cgroup_ns(struct cgroup_namespace *ns) { } | |
711 | static inline struct cgroup_namespace * | |
712 | copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns, | |
713 | struct cgroup_namespace *old_ns) | |
714 | { | |
715 | return old_ns; | |
716 | } | |
717 | ||
718 | #endif /* !CONFIG_CGROUPS */ | |
719 | ||
720 | static inline void get_cgroup_ns(struct cgroup_namespace *ns) | |
721 | { | |
722 | if (ns) | |
387ad967 | 723 | refcount_inc(&ns->count); |
a79a908f AK |
724 | } |
725 | ||
726 | static inline void put_cgroup_ns(struct cgroup_namespace *ns) | |
727 | { | |
387ad967 | 728 | if (ns && refcount_dec_and_test(&ns->count)) |
a79a908f AK |
729 | free_cgroup_ns(ns); |
730 | } | |
731 | ||
ddbcc7e8 | 732 | #endif /* _LINUX_CGROUP_H */ |