1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_CGROUP_H 3 #define _LINUX_CGROUP_H 4 /* 5 * cgroup interface 6 * 7 * Copyright (C) 2003 BULL SA 8 * Copyright (C) 2004-2006 Silicon Graphics, Inc. 9 * 10 */ 11 12 #include <linux/sched.h> 13 #include <linux/cpumask.h> 14 #include <linux/nodemask.h> 15 #include <linux/rculist.h> 16 #include <linux/cgroupstats.h> 17 #include <linux/fs.h> 18 #include <linux/seq_file.h> 19 #include <linux/kernfs.h> 20 #include <linux/jump_label.h> 21 #include <linux/types.h> 22 #include <linux/ns_common.h> 23 #include <linux/nsproxy.h> 24 #include <linux/user_namespace.h> 25 #include <linux/refcount.h> 26 #include <linux/kernel_stat.h> 27 28 #include <linux/cgroup-defs.h> 29 30 struct kernel_clone_args; 31 32 #ifdef CONFIG_CGROUPS 33 34 /* 35 * All weight knobs on the default hierarchy should use the following min, 36 * default and max values. The default value is the logarithmic center of 37 * MIN and MAX and allows 100x to be expressed in both directions. 38 */ 39 #define CGROUP_WEIGHT_MIN 1 40 #define CGROUP_WEIGHT_DFL 100 41 #define CGROUP_WEIGHT_MAX 10000 42 43 /* walk only threadgroup leaders */ 44 #define CSS_TASK_ITER_PROCS (1U << 0) 45 /* walk all threaded css_sets in the domain */ 46 #define CSS_TASK_ITER_THREADED (1U << 1) 47 48 /* internal flags */ 49 #define CSS_TASK_ITER_SKIPPED (1U << 16) 50 51 /* a css_task_iter should be treated as an opaque object */ 52 struct css_task_iter { 53 struct cgroup_subsys *ss; 54 unsigned int flags; 55 56 struct list_head *cset_pos; 57 struct list_head *cset_head; 58 59 struct list_head *tcset_pos; 60 struct list_head *tcset_head; 61 62 struct list_head *task_pos; 63 64 struct list_head *cur_tasks_head; 65 struct css_set *cur_cset; 66 struct css_set *cur_dcset; 67 struct task_struct *cur_task; 68 struct list_head iters_node; /* css_set->task_iters */ 69 }; 70 71 extern struct cgroup_root cgrp_dfl_root; 72 extern struct css_set init_css_set; 73 74 #define SUBSYS(_x) extern struct cgroup_subsys _x ## _cgrp_subsys; 75 #include <linux/cgroup_subsys.h> 76 #undef SUBSYS 77 78 #define SUBSYS(_x) \ 79 extern struct static_key_true _x ## _cgrp_subsys_enabled_key; \ 80 extern struct static_key_true _x ## _cgrp_subsys_on_dfl_key; 81 #include <linux/cgroup_subsys.h> 82 #undef SUBSYS 83 84 /** 85 * cgroup_subsys_enabled - fast test on whether a subsys is enabled 86 * @ss: subsystem in question 87 */ 88 #define cgroup_subsys_enabled(ss) \ 89 static_branch_likely(&ss ## _enabled_key) 90 91 /** 92 * cgroup_subsys_on_dfl - fast test on whether a subsys is on default hierarchy 93 * @ss: subsystem in question 94 */ 95 #define cgroup_subsys_on_dfl(ss) \ 96 static_branch_likely(&ss ## _on_dfl_key) 97 98 bool css_has_online_children(struct cgroup_subsys_state *css); 99 struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss); 100 struct cgroup_subsys_state *cgroup_e_css(struct cgroup *cgroup, 101 struct cgroup_subsys *ss); 102 struct cgroup_subsys_state *cgroup_get_e_css(struct cgroup *cgroup, 103 struct cgroup_subsys *ss); 104 struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry, 105 struct cgroup_subsys *ss); 106 107 struct cgroup *cgroup_get_from_path(const char *path); 108 struct cgroup *cgroup_get_from_fd(int fd); 109 struct cgroup *cgroup_v1v2_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 void cgroup_file_show(struct cgroup_file *cfile, bool show); 119 120 int task_cgroup_path(struct task_struct *task, char *buf, size_t buflen); 121 int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry); 122 int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns, 123 struct pid *pid, struct task_struct *tsk); 124 125 void cgroup_fork(struct task_struct *p); 126 extern int cgroup_can_fork(struct task_struct *p, 127 struct kernel_clone_args *kargs); 128 extern void cgroup_cancel_fork(struct task_struct *p, 129 struct kernel_clone_args *kargs); 130 extern void cgroup_post_fork(struct task_struct *p, 131 struct kernel_clone_args *kargs); 132 void cgroup_exit(struct task_struct *p); 133 void cgroup_release(struct task_struct *p); 134 void cgroup_free(struct task_struct *p); 135 136 int cgroup_init_early(void); 137 int cgroup_init(void); 138 139 int cgroup_parse_float(const char *input, unsigned dec_shift, s64 *v); 140 141 /* 142 * Iteration helpers and macros. 143 */ 144 145 struct cgroup_subsys_state *css_next_child(struct cgroup_subsys_state *pos, 146 struct cgroup_subsys_state *parent); 147 struct cgroup_subsys_state *css_next_descendant_pre(struct cgroup_subsys_state *pos, 148 struct cgroup_subsys_state *css); 149 struct cgroup_subsys_state *css_rightmost_descendant(struct cgroup_subsys_state *pos); 150 struct cgroup_subsys_state *css_next_descendant_post(struct cgroup_subsys_state *pos, 151 struct cgroup_subsys_state *css); 152 153 struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset, 154 struct cgroup_subsys_state **dst_cssp); 155 struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset, 156 struct cgroup_subsys_state **dst_cssp); 157 158 void css_task_iter_start(struct cgroup_subsys_state *css, unsigned int flags, 159 struct css_task_iter *it); 160 struct task_struct *css_task_iter_next(struct css_task_iter *it); 161 void css_task_iter_end(struct css_task_iter *it); 162 163 /** 164 * css_for_each_child - iterate through children of a css 165 * @pos: the css * to use as the loop cursor 166 * @parent: css whose children to walk 167 * 168 * Walk @parent's children. Must be called under rcu_read_lock(). 169 * 170 * If a subsystem synchronizes ->css_online() and the start of iteration, a 171 * css which finished ->css_online() is guaranteed to be visible in the 172 * future iterations and will stay visible until the last reference is put. 173 * A css which hasn't finished ->css_online() or already finished 174 * ->css_offline() may show up during traversal. It's each subsystem's 175 * responsibility to synchronize against on/offlining. 176 * 177 * It is allowed to temporarily drop RCU read lock during iteration. The 178 * caller is responsible for ensuring that @pos remains accessible until 179 * the start of the next iteration by, for example, bumping the css refcnt. 180 */ 181 #define css_for_each_child(pos, parent) \ 182 for ((pos) = css_next_child(NULL, (parent)); (pos); \ 183 (pos) = css_next_child((pos), (parent))) 184 185 /** 186 * css_for_each_descendant_pre - pre-order walk of a css's descendants 187 * @pos: the css * to use as the loop cursor 188 * @root: css whose descendants to walk 189 * 190 * Walk @root's descendants. @root is included in the iteration and the 191 * first node to be visited. Must be called under rcu_read_lock(). 192 * 193 * If a subsystem synchronizes ->css_online() and the start of iteration, a 194 * css which finished ->css_online() is guaranteed to be visible in the 195 * future iterations and will stay visible until the last reference is put. 196 * A css which hasn't finished ->css_online() or already finished 197 * ->css_offline() may show up during traversal. It's each subsystem's 198 * responsibility to synchronize against on/offlining. 199 * 200 * For example, the following guarantees that a descendant can't escape 201 * state updates of its ancestors. 202 * 203 * my_online(@css) 204 * { 205 * Lock @css's parent and @css; 206 * Inherit state from the parent; 207 * Unlock both. 208 * } 209 * 210 * my_update_state(@css) 211 * { 212 * css_for_each_descendant_pre(@pos, @css) { 213 * Lock @pos; 214 * if (@pos == @css) 215 * Update @css's state; 216 * else 217 * Verify @pos is alive and inherit state from its parent; 218 * Unlock @pos; 219 * } 220 * } 221 * 222 * As long as the inheriting step, including checking the parent state, is 223 * enclosed inside @pos locking, double-locking the parent isn't necessary 224 * while inheriting. The state update to the parent is guaranteed to be 225 * visible by walking order and, as long as inheriting operations to the 226 * same @pos are atomic to each other, multiple updates racing each other 227 * still result in the correct state. It's guaranateed that at least one 228 * inheritance happens for any css after the latest update to its parent. 229 * 230 * If checking parent's state requires locking the parent, each inheriting 231 * iteration should lock and unlock both @pos->parent and @pos. 232 * 233 * Alternatively, a subsystem may choose to use a single global lock to 234 * synchronize ->css_online() and ->css_offline() against tree-walking 235 * operations. 236 * 237 * It is allowed to temporarily drop RCU read lock during iteration. The 238 * caller is responsible for ensuring that @pos remains accessible until 239 * the start of the next iteration by, for example, bumping the css refcnt. 240 */ 241 #define css_for_each_descendant_pre(pos, css) \ 242 for ((pos) = css_next_descendant_pre(NULL, (css)); (pos); \ 243 (pos) = css_next_descendant_pre((pos), (css))) 244 245 /** 246 * css_for_each_descendant_post - post-order walk of a css's descendants 247 * @pos: the css * to use as the loop cursor 248 * @css: css whose descendants to walk 249 * 250 * Similar to css_for_each_descendant_pre() but performs post-order 251 * traversal instead. @root is included in the iteration and the last 252 * node to be visited. 253 * 254 * If a subsystem synchronizes ->css_online() and the start of iteration, a 255 * css which finished ->css_online() is guaranteed to be visible in the 256 * future iterations and will stay visible until the last reference is put. 257 * A css which hasn't finished ->css_online() or already finished 258 * ->css_offline() may show up during traversal. It's each subsystem's 259 * responsibility to synchronize against on/offlining. 260 * 261 * Note that the walk visibility guarantee example described in pre-order 262 * walk doesn't apply the same to post-order walks. 263 */ 264 #define css_for_each_descendant_post(pos, css) \ 265 for ((pos) = css_next_descendant_post(NULL, (css)); (pos); \ 266 (pos) = css_next_descendant_post((pos), (css))) 267 268 /** 269 * cgroup_taskset_for_each - iterate cgroup_taskset 270 * @task: the loop cursor 271 * @dst_css: the destination css 272 * @tset: taskset to iterate 273 * 274 * @tset may contain multiple tasks and they may belong to multiple 275 * processes. 276 * 277 * On the v2 hierarchy, there may be tasks from multiple processes and they 278 * may not share the source or destination csses. 279 * 280 * On traditional hierarchies, when there are multiple tasks in @tset, if a 281 * task of a process is in @tset, all tasks of the process are in @tset. 282 * Also, all are guaranteed to share the same source and destination csses. 283 * 284 * Iteration is not in any specific order. 285 */ 286 #define cgroup_taskset_for_each(task, dst_css, tset) \ 287 for ((task) = cgroup_taskset_first((tset), &(dst_css)); \ 288 (task); \ 289 (task) = cgroup_taskset_next((tset), &(dst_css))) 290 291 /** 292 * cgroup_taskset_for_each_leader - iterate group leaders in a cgroup_taskset 293 * @leader: the loop cursor 294 * @dst_css: the destination css 295 * @tset: taskset to iterate 296 * 297 * Iterate threadgroup leaders of @tset. For single-task migrations, @tset 298 * may not contain any. 299 */ 300 #define cgroup_taskset_for_each_leader(leader, dst_css, tset) \ 301 for ((leader) = cgroup_taskset_first((tset), &(dst_css)); \ 302 (leader); \ 303 (leader) = cgroup_taskset_next((tset), &(dst_css))) \ 304 if ((leader) != (leader)->group_leader) \ 305 ; \ 306 else 307 308 /* 309 * Inline functions. 310 */ 311 312 static inline u64 cgroup_id(const struct cgroup *cgrp) 313 { 314 return cgrp->kn->id; 315 } 316 317 /** 318 * css_get - obtain a reference on the specified css 319 * @css: target css 320 * 321 * The caller must already have a reference. 322 */ 323 static inline void css_get(struct cgroup_subsys_state *css) 324 { 325 if (!(css->flags & CSS_NO_REF)) 326 percpu_ref_get(&css->refcnt); 327 } 328 329 /** 330 * css_get_many - obtain references on the specified css 331 * @css: target css 332 * @n: number of references to get 333 * 334 * The caller must already have a reference. 335 */ 336 static inline void css_get_many(struct cgroup_subsys_state *css, unsigned int n) 337 { 338 if (!(css->flags & CSS_NO_REF)) 339 percpu_ref_get_many(&css->refcnt, n); 340 } 341 342 /** 343 * css_tryget - try to obtain a reference on the specified css 344 * @css: target css 345 * 346 * Obtain a reference on @css unless it already has reached zero and is 347 * being released. This function doesn't care whether @css is on or 348 * offline. The caller naturally needs to ensure that @css is accessible 349 * but doesn't have to be holding a reference on it - IOW, RCU protected 350 * access is good enough for this function. Returns %true if a reference 351 * count was successfully obtained; %false otherwise. 352 */ 353 static inline bool css_tryget(struct cgroup_subsys_state *css) 354 { 355 if (!(css->flags & CSS_NO_REF)) 356 return percpu_ref_tryget(&css->refcnt); 357 return true; 358 } 359 360 /** 361 * css_tryget_online - try to obtain a reference on the specified css if online 362 * @css: target css 363 * 364 * Obtain a reference on @css if it's online. The caller naturally needs 365 * to ensure that @css is accessible but doesn't have to be holding a 366 * reference on it - IOW, RCU protected access is good enough for this 367 * function. Returns %true if a reference count was successfully obtained; 368 * %false otherwise. 369 */ 370 static inline bool css_tryget_online(struct cgroup_subsys_state *css) 371 { 372 if (!(css->flags & CSS_NO_REF)) 373 return percpu_ref_tryget_live(&css->refcnt); 374 return true; 375 } 376 377 /** 378 * css_is_dying - test whether the specified css is dying 379 * @css: target css 380 * 381 * Test whether @css is in the process of offlining or already offline. In 382 * most cases, ->css_online() and ->css_offline() callbacks should be 383 * enough; however, the actual offline operations are RCU delayed and this 384 * test returns %true also when @css is scheduled to be offlined. 385 * 386 * This is useful, for example, when the use case requires synchronous 387 * behavior with respect to cgroup removal. cgroup removal schedules css 388 * offlining but the css can seem alive while the operation is being 389 * delayed. If the delay affects user visible semantics, this test can be 390 * used to resolve the situation. 391 */ 392 static inline bool css_is_dying(struct cgroup_subsys_state *css) 393 { 394 return !(css->flags & CSS_NO_REF) && percpu_ref_is_dying(&css->refcnt); 395 } 396 397 /** 398 * css_put - put a css reference 399 * @css: target css 400 * 401 * Put a reference obtained via css_get() and css_tryget_online(). 402 */ 403 static inline void css_put(struct cgroup_subsys_state *css) 404 { 405 if (!(css->flags & CSS_NO_REF)) 406 percpu_ref_put(&css->refcnt); 407 } 408 409 /** 410 * css_put_many - put css references 411 * @css: target css 412 * @n: number of references to put 413 * 414 * Put references obtained via css_get() and css_tryget_online(). 415 */ 416 static inline void css_put_many(struct cgroup_subsys_state *css, unsigned int n) 417 { 418 if (!(css->flags & CSS_NO_REF)) 419 percpu_ref_put_many(&css->refcnt, n); 420 } 421 422 static inline void cgroup_get(struct cgroup *cgrp) 423 { 424 css_get(&cgrp->self); 425 } 426 427 static inline bool cgroup_tryget(struct cgroup *cgrp) 428 { 429 return css_tryget(&cgrp->self); 430 } 431 432 static inline void cgroup_put(struct cgroup *cgrp) 433 { 434 css_put(&cgrp->self); 435 } 436 437 extern struct mutex cgroup_mutex; 438 439 static inline void cgroup_lock(void) 440 { 441 mutex_lock(&cgroup_mutex); 442 } 443 444 static inline void cgroup_unlock(void) 445 { 446 mutex_unlock(&cgroup_mutex); 447 } 448 449 /** 450 * task_css_set_check - obtain a task's css_set with extra access conditions 451 * @task: the task to obtain css_set for 452 * @__c: extra condition expression to be passed to rcu_dereference_check() 453 * 454 * A task's css_set is RCU protected, initialized and exited while holding 455 * task_lock(), and can only be modified while holding both cgroup_mutex 456 * and task_lock() while the task is alive. This macro verifies that the 457 * caller is inside proper critical section and returns @task's css_set. 458 * 459 * The caller can also specify additional allowed conditions via @__c, such 460 * as locks used during the cgroup_subsys::attach() methods. 461 */ 462 #ifdef CONFIG_PROVE_RCU 463 extern spinlock_t css_set_lock; 464 #define task_css_set_check(task, __c) \ 465 rcu_dereference_check((task)->cgroups, \ 466 rcu_read_lock_sched_held() || \ 467 lockdep_is_held(&cgroup_mutex) || \ 468 lockdep_is_held(&css_set_lock) || \ 469 ((task)->flags & PF_EXITING) || (__c)) 470 #else 471 #define task_css_set_check(task, __c) \ 472 rcu_dereference((task)->cgroups) 473 #endif 474 475 /** 476 * task_css_check - obtain css for (task, subsys) w/ extra access conds 477 * @task: the target task 478 * @subsys_id: the target subsystem ID 479 * @__c: extra condition expression to be passed to rcu_dereference_check() 480 * 481 * Return the cgroup_subsys_state for the (@task, @subsys_id) pair. The 482 * synchronization rules are the same as task_css_set_check(). 483 */ 484 #define task_css_check(task, subsys_id, __c) \ 485 task_css_set_check((task), (__c))->subsys[(subsys_id)] 486 487 /** 488 * task_css_set - obtain a task's css_set 489 * @task: the task to obtain css_set for 490 * 491 * See task_css_set_check(). 492 */ 493 static inline struct css_set *task_css_set(struct task_struct *task) 494 { 495 return task_css_set_check(task, false); 496 } 497 498 /** 499 * task_css - obtain css for (task, subsys) 500 * @task: the target task 501 * @subsys_id: the target subsystem ID 502 * 503 * See task_css_check(). 504 */ 505 static inline struct cgroup_subsys_state *task_css(struct task_struct *task, 506 int subsys_id) 507 { 508 return task_css_check(task, subsys_id, false); 509 } 510 511 /** 512 * task_get_css - find and get the css for (task, subsys) 513 * @task: the target task 514 * @subsys_id: the target subsystem ID 515 * 516 * Find the css for the (@task, @subsys_id) combination, increment a 517 * reference on and return it. This function is guaranteed to return a 518 * valid css. The returned css may already have been offlined. 519 */ 520 static inline struct cgroup_subsys_state * 521 task_get_css(struct task_struct *task, int subsys_id) 522 { 523 struct cgroup_subsys_state *css; 524 525 rcu_read_lock(); 526 while (true) { 527 css = task_css(task, subsys_id); 528 /* 529 * Can't use css_tryget_online() here. A task which has 530 * PF_EXITING set may stay associated with an offline css. 531 * If such task calls this function, css_tryget_online() 532 * will keep failing. 533 */ 534 if (likely(css_tryget(css))) 535 break; 536 cpu_relax(); 537 } 538 rcu_read_unlock(); 539 return css; 540 } 541 542 /** 543 * task_css_is_root - test whether a task belongs to the root css 544 * @task: the target task 545 * @subsys_id: the target subsystem ID 546 * 547 * Test whether @task belongs to the root css on the specified subsystem. 548 * May be invoked in any context. 549 */ 550 static inline bool task_css_is_root(struct task_struct *task, int subsys_id) 551 { 552 return task_css_check(task, subsys_id, true) == 553 init_css_set.subsys[subsys_id]; 554 } 555 556 static inline struct cgroup *task_cgroup(struct task_struct *task, 557 int subsys_id) 558 { 559 return task_css(task, subsys_id)->cgroup; 560 } 561 562 static inline struct cgroup *task_dfl_cgroup(struct task_struct *task) 563 { 564 return task_css_set(task)->dfl_cgrp; 565 } 566 567 static inline struct cgroup *cgroup_parent(struct cgroup *cgrp) 568 { 569 struct cgroup_subsys_state *parent_css = cgrp->self.parent; 570 571 if (parent_css) 572 return container_of(parent_css, struct cgroup, self); 573 return NULL; 574 } 575 576 /** 577 * cgroup_is_descendant - test ancestry 578 * @cgrp: the cgroup to be tested 579 * @ancestor: possible ancestor of @cgrp 580 * 581 * Test whether @cgrp is a descendant of @ancestor. It also returns %true 582 * if @cgrp == @ancestor. This function is safe to call as long as @cgrp 583 * and @ancestor are accessible. 584 */ 585 static inline bool cgroup_is_descendant(struct cgroup *cgrp, 586 struct cgroup *ancestor) 587 { 588 if (cgrp->root != ancestor->root || cgrp->level < ancestor->level) 589 return false; 590 return cgrp->ancestors[ancestor->level] == ancestor; 591 } 592 593 /** 594 * cgroup_ancestor - find ancestor of cgroup 595 * @cgrp: cgroup to find ancestor of 596 * @ancestor_level: level of ancestor to find starting from root 597 * 598 * Find ancestor of cgroup at specified level starting from root if it exists 599 * and return pointer to it. Return NULL if @cgrp doesn't have ancestor at 600 * @ancestor_level. 601 * 602 * This function is safe to call as long as @cgrp is accessible. 603 */ 604 static inline struct cgroup *cgroup_ancestor(struct cgroup *cgrp, 605 int ancestor_level) 606 { 607 if (ancestor_level < 0 || ancestor_level > cgrp->level) 608 return NULL; 609 return cgrp->ancestors[ancestor_level]; 610 } 611 612 /** 613 * task_under_cgroup_hierarchy - test task's membership of cgroup ancestry 614 * @task: the task to be tested 615 * @ancestor: possible ancestor of @task's cgroup 616 * 617 * Tests whether @task's default cgroup hierarchy is a descendant of @ancestor. 618 * It follows all the same rules as cgroup_is_descendant, and only applies 619 * to the default hierarchy. 620 */ 621 static inline bool task_under_cgroup_hierarchy(struct task_struct *task, 622 struct cgroup *ancestor) 623 { 624 struct css_set *cset = task_css_set(task); 625 626 return cgroup_is_descendant(cset->dfl_cgrp, ancestor); 627 } 628 629 /* no synchronization, the result can only be used as a hint */ 630 static inline bool cgroup_is_populated(struct cgroup *cgrp) 631 { 632 return cgrp->nr_populated_csets + cgrp->nr_populated_domain_children + 633 cgrp->nr_populated_threaded_children; 634 } 635 636 /* returns ino associated with a cgroup */ 637 static inline ino_t cgroup_ino(struct cgroup *cgrp) 638 { 639 return kernfs_ino(cgrp->kn); 640 } 641 642 /* cft/css accessors for cftype->write() operation */ 643 static inline struct cftype *of_cft(struct kernfs_open_file *of) 644 { 645 return of->kn->priv; 646 } 647 648 struct cgroup_subsys_state *of_css(struct kernfs_open_file *of); 649 650 /* cft/css accessors for cftype->seq_*() operations */ 651 static inline struct cftype *seq_cft(struct seq_file *seq) 652 { 653 return of_cft(seq->private); 654 } 655 656 static inline struct cgroup_subsys_state *seq_css(struct seq_file *seq) 657 { 658 return of_css(seq->private); 659 } 660 661 /* 662 * Name / path handling functions. All are thin wrappers around the kernfs 663 * counterparts and can be called under any context. 664 */ 665 666 static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen) 667 { 668 return kernfs_name(cgrp->kn, buf, buflen); 669 } 670 671 static inline int cgroup_path(struct cgroup *cgrp, char *buf, size_t buflen) 672 { 673 return kernfs_path(cgrp->kn, buf, buflen); 674 } 675 676 static inline void pr_cont_cgroup_name(struct cgroup *cgrp) 677 { 678 pr_cont_kernfs_name(cgrp->kn); 679 } 680 681 static inline void pr_cont_cgroup_path(struct cgroup *cgrp) 682 { 683 pr_cont_kernfs_path(cgrp->kn); 684 } 685 686 bool cgroup_psi_enabled(void); 687 688 static inline void cgroup_init_kthreadd(void) 689 { 690 /* 691 * kthreadd is inherited by all kthreads, keep it in the root so 692 * that the new kthreads are guaranteed to stay in the root until 693 * initialization is finished. 694 */ 695 current->no_cgroup_migration = 1; 696 } 697 698 static inline void cgroup_kthread_ready(void) 699 { 700 /* 701 * This kthread finished initialization. The creator should have 702 * set PF_NO_SETAFFINITY if this kthread should stay in the root. 703 */ 704 current->no_cgroup_migration = 0; 705 } 706 707 void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen); 708 struct cgroup *cgroup_get_from_id(u64 id); 709 #else /* !CONFIG_CGROUPS */ 710 711 struct cgroup_subsys_state; 712 struct cgroup; 713 714 static inline u64 cgroup_id(const struct cgroup *cgrp) { return 1; } 715 static inline void css_get(struct cgroup_subsys_state *css) {} 716 static inline void css_put(struct cgroup_subsys_state *css) {} 717 static inline void cgroup_lock(void) {} 718 static inline void cgroup_unlock(void) {} 719 static inline int cgroup_attach_task_all(struct task_struct *from, 720 struct task_struct *t) { return 0; } 721 static inline int cgroupstats_build(struct cgroupstats *stats, 722 struct dentry *dentry) { return -EINVAL; } 723 724 static inline void cgroup_fork(struct task_struct *p) {} 725 static inline int cgroup_can_fork(struct task_struct *p, 726 struct kernel_clone_args *kargs) { return 0; } 727 static inline void cgroup_cancel_fork(struct task_struct *p, 728 struct kernel_clone_args *kargs) {} 729 static inline void cgroup_post_fork(struct task_struct *p, 730 struct kernel_clone_args *kargs) {} 731 static inline void cgroup_exit(struct task_struct *p) {} 732 static inline void cgroup_release(struct task_struct *p) {} 733 static inline void cgroup_free(struct task_struct *p) {} 734 735 static inline int cgroup_init_early(void) { return 0; } 736 static inline int cgroup_init(void) { return 0; } 737 static inline void cgroup_init_kthreadd(void) {} 738 static inline void cgroup_kthread_ready(void) {} 739 740 static inline struct cgroup *cgroup_parent(struct cgroup *cgrp) 741 { 742 return NULL; 743 } 744 745 static inline bool cgroup_psi_enabled(void) 746 { 747 return false; 748 } 749 750 static inline bool task_under_cgroup_hierarchy(struct task_struct *task, 751 struct cgroup *ancestor) 752 { 753 return true; 754 } 755 756 static inline void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen) 757 {} 758 #endif /* !CONFIG_CGROUPS */ 759 760 #ifdef CONFIG_CGROUPS 761 /* 762 * cgroup scalable recursive statistics. 763 */ 764 void cgroup_rstat_updated(struct cgroup *cgrp, int cpu); 765 void cgroup_rstat_flush(struct cgroup *cgrp); 766 void cgroup_rstat_flush_irqsafe(struct cgroup *cgrp); 767 void cgroup_rstat_flush_hold(struct cgroup *cgrp); 768 void cgroup_rstat_flush_release(void); 769 770 /* 771 * Basic resource stats. 772 */ 773 #ifdef CONFIG_CGROUP_CPUACCT 774 void cpuacct_charge(struct task_struct *tsk, u64 cputime); 775 void cpuacct_account_field(struct task_struct *tsk, int index, u64 val); 776 #else 777 static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {} 778 static inline void cpuacct_account_field(struct task_struct *tsk, int index, 779 u64 val) {} 780 #endif 781 782 void __cgroup_account_cputime(struct cgroup *cgrp, u64 delta_exec); 783 void __cgroup_account_cputime_field(struct cgroup *cgrp, 784 enum cpu_usage_stat index, u64 delta_exec); 785 786 static inline void cgroup_account_cputime(struct task_struct *task, 787 u64 delta_exec) 788 { 789 struct cgroup *cgrp; 790 791 cpuacct_charge(task, delta_exec); 792 793 cgrp = task_dfl_cgroup(task); 794 if (cgroup_parent(cgrp)) 795 __cgroup_account_cputime(cgrp, delta_exec); 796 } 797 798 static inline void cgroup_account_cputime_field(struct task_struct *task, 799 enum cpu_usage_stat index, 800 u64 delta_exec) 801 { 802 struct cgroup *cgrp; 803 804 cpuacct_account_field(task, index, delta_exec); 805 806 cgrp = task_dfl_cgroup(task); 807 if (cgroup_parent(cgrp)) 808 __cgroup_account_cputime_field(cgrp, index, delta_exec); 809 } 810 811 #else /* CONFIG_CGROUPS */ 812 813 static inline void cgroup_account_cputime(struct task_struct *task, 814 u64 delta_exec) {} 815 static inline void cgroup_account_cputime_field(struct task_struct *task, 816 enum cpu_usage_stat index, 817 u64 delta_exec) {} 818 819 #endif /* CONFIG_CGROUPS */ 820 821 /* 822 * sock->sk_cgrp_data handling. For more info, see sock_cgroup_data 823 * definition in cgroup-defs.h. 824 */ 825 #ifdef CONFIG_SOCK_CGROUP_DATA 826 827 void cgroup_sk_alloc(struct sock_cgroup_data *skcd); 828 void cgroup_sk_clone(struct sock_cgroup_data *skcd); 829 void cgroup_sk_free(struct sock_cgroup_data *skcd); 830 831 static inline struct cgroup *sock_cgroup_ptr(struct sock_cgroup_data *skcd) 832 { 833 return skcd->cgroup; 834 } 835 836 #else /* CONFIG_CGROUP_DATA */ 837 838 static inline void cgroup_sk_alloc(struct sock_cgroup_data *skcd) {} 839 static inline void cgroup_sk_clone(struct sock_cgroup_data *skcd) {} 840 static inline void cgroup_sk_free(struct sock_cgroup_data *skcd) {} 841 842 #endif /* CONFIG_CGROUP_DATA */ 843 844 struct cgroup_namespace { 845 struct ns_common ns; 846 struct user_namespace *user_ns; 847 struct ucounts *ucounts; 848 struct css_set *root_cset; 849 }; 850 851 extern struct cgroup_namespace init_cgroup_ns; 852 853 #ifdef CONFIG_CGROUPS 854 855 void free_cgroup_ns(struct cgroup_namespace *ns); 856 857 struct cgroup_namespace *copy_cgroup_ns(unsigned long flags, 858 struct user_namespace *user_ns, 859 struct cgroup_namespace *old_ns); 860 861 int cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen, 862 struct cgroup_namespace *ns); 863 864 #else /* !CONFIG_CGROUPS */ 865 866 static inline void free_cgroup_ns(struct cgroup_namespace *ns) { } 867 static inline struct cgroup_namespace * 868 copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns, 869 struct cgroup_namespace *old_ns) 870 { 871 return old_ns; 872 } 873 874 #endif /* !CONFIG_CGROUPS */ 875 876 static inline void get_cgroup_ns(struct cgroup_namespace *ns) 877 { 878 if (ns) 879 refcount_inc(&ns->ns.count); 880 } 881 882 static inline void put_cgroup_ns(struct cgroup_namespace *ns) 883 { 884 if (ns && refcount_dec_and_test(&ns->ns.count)) 885 free_cgroup_ns(ns); 886 } 887 888 #ifdef CONFIG_CGROUPS 889 890 void cgroup_enter_frozen(void); 891 void cgroup_leave_frozen(bool always_leave); 892 void cgroup_update_frozen(struct cgroup *cgrp); 893 void cgroup_freeze(struct cgroup *cgrp, bool freeze); 894 void cgroup_freezer_migrate_task(struct task_struct *task, struct cgroup *src, 895 struct cgroup *dst); 896 897 static inline bool cgroup_task_frozen(struct task_struct *task) 898 { 899 return task->frozen; 900 } 901 902 #else /* !CONFIG_CGROUPS */ 903 904 static inline void cgroup_enter_frozen(void) { } 905 static inline void cgroup_leave_frozen(bool always_leave) { } 906 static inline bool cgroup_task_frozen(struct task_struct *task) 907 { 908 return false; 909 } 910 911 #endif /* !CONFIG_CGROUPS */ 912 913 #ifdef CONFIG_CGROUP_BPF 914 static inline void cgroup_bpf_get(struct cgroup *cgrp) 915 { 916 percpu_ref_get(&cgrp->bpf.refcnt); 917 } 918 919 static inline void cgroup_bpf_put(struct cgroup *cgrp) 920 { 921 percpu_ref_put(&cgrp->bpf.refcnt); 922 } 923 924 #else /* CONFIG_CGROUP_BPF */ 925 926 static inline void cgroup_bpf_get(struct cgroup *cgrp) {} 927 static inline void cgroup_bpf_put(struct cgroup *cgrp) {} 928 929 #endif /* CONFIG_CGROUP_BPF */ 930 931 #endif /* _LINUX_CGROUP_H */ 932