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> 12 #include <linux/cpumask.h> 13 #include <linux/nodemask.h> 14 #include <linux/rculist.h> 15 #include <linux/cgroupstats.h> 16 #include <linux/fs.h> 17 #include <linux/seq_file.h> 18 #include <linux/kernfs.h> 19 #include <linux/jump_label.h> 20 #include <linux/types.h> 21 #include <linux/ns_common.h> 22 #include <linux/nsproxy.h> 23 #include <linux/user_namespace.h> 24 #include <linux/refcount.h> 25 26 #include <linux/cgroup-defs.h> 27 28 #ifdef CONFIG_CGROUPS 29 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 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; 45 46 struct list_head *task_pos; 47 struct list_head *tasks_head; 48 struct list_head *mg_tasks_head; 49 50 struct css_set *cur_cset; 51 struct task_struct *cur_task; 52 struct list_head iters_node; /* css_set->task_iters */ 53 }; 54 55 extern struct cgroup_root cgrp_dfl_root; 56 extern struct css_set init_css_set; 57 58 #define SUBSYS(_x) extern struct cgroup_subsys _x ## _cgrp_subsys; 59 #include <linux/cgroup_subsys.h> 60 #undef SUBSYS 61 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 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 89 struct cgroup *cgroup_get_from_path(const char *path); 90 struct cgroup *cgroup_get_from_fd(int fd); 91 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); 98 void cgroup_file_notify(struct cgroup_file *cfile); 99 100 int 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); 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); 109 void cgroup_exit(struct task_struct *p); 110 void cgroup_free(struct task_struct *p); 111 112 int cgroup_init_early(void); 113 int cgroup_init(void); 114 115 /* 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); 126 127 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); 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. 150 * 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. 154 */ 155 #define css_for_each_child(pos, parent) \ 156 for ((pos) = css_next_child(NULL, (parent)); (pos); \ 157 (pos) = css_next_child((pos), (parent))) 158 159 /** 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 245 * @dst_css: the destination css 246 * @tset: taskset to iterate 247 * 248 * @tset may contain multiple tasks and they may belong to multiple 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. 257 * 258 * Iteration is not in any specific order. 259 */ 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))) 264 265 /** 266 * cgroup_taskset_for_each_leader - iterate group leaders in a cgroup_taskset 267 * @leader: the loop cursor 268 * @dst_css: the destination css 269 * @tset: taskset to iterate 270 * 271 * Iterate threadgroup leaders of @tset. For single-task migrations, @tset 272 * may not contain any. 273 */ 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))) \ 278 if ((leader) != (leader)->group_leader) \ 279 ; \ 280 else 281 282 /* 283 * Inline functions. 284 */ 285 286 /** 287 * css_get - obtain a reference on the specified css 288 * @css: target css 289 * 290 * The caller must already have a reference. 291 */ 292 static inline void css_get(struct cgroup_subsys_state *css) 293 { 294 if (!(css->flags & CSS_NO_REF)) 295 percpu_ref_get(&css->refcnt); 296 } 297 298 /** 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 } 310 311 /** 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 } 328 329 /** 330 * css_tryget_online - try to obtain a reference on the specified css if online 331 * @css: target css 332 * 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 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 */ 339 static inline bool css_tryget_online(struct cgroup_subsys_state *css) 340 { 341 if (!(css->flags & CSS_NO_REF)) 342 return percpu_ref_tryget_live(&css->refcnt); 343 return true; 344 } 345 346 /** 347 * css_put - put a css reference 348 * @css: target css 349 * 350 * Put a reference obtained via css_get() and css_tryget_online(). 351 */ 352 static inline void css_put(struct cgroup_subsys_state *css) 353 { 354 if (!(css->flags & CSS_NO_REF)) 355 percpu_ref_put(&css->refcnt); 356 } 357 358 /** 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(). 364 */ 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 } 370 371 static inline void cgroup_put(struct cgroup *cgrp) 372 { 373 css_put(&cgrp->self); 374 } 375 376 /** 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. 388 */ 389 #ifdef CONFIG_PROVE_RCU 390 extern struct mutex cgroup_mutex; 391 extern spinlock_t css_set_lock; 392 #define task_css_set_check(task, __c) \ 393 rcu_dereference_check((task)->cgroups, \ 394 lockdep_is_held(&cgroup_mutex) || \ 395 lockdep_is_held(&css_set_lock) || \ 396 ((task)->flags & PF_EXITING) || (__c)) 397 #else 398 #define task_css_set_check(task, __c) \ 399 rcu_dereference((task)->cgroups) 400 #endif 401 402 /** 403 * task_css_check - obtain css for (task, subsys) w/ extra access conds 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 */ 411 #define task_css_check(task, subsys_id, __c) \ 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 /** 426 * task_css - obtain css for (task, subsys) 427 * @task: the target task 428 * @subsys_id: the target subsystem ID 429 * 430 * See task_css_check(). 431 */ 432 static inline struct cgroup_subsys_state *task_css(struct task_struct *task, 433 int subsys_id) 434 { 435 return task_css_check(task, subsys_id, false); 436 } 437 438 /** 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 } 462 463 /** 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 } 476 477 static inline struct cgroup *task_cgroup(struct task_struct *task, 478 int subsys_id) 479 { 480 return task_css(task, subsys_id)->cgroup; 481 } 482 483 /** 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 } 499 500 /** 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 } 516 517 /* no synchronization, the result can only be used as a hint */ 518 static inline bool cgroup_is_populated(struct cgroup *cgrp) 519 { 520 return cgrp->populated_cnt; 521 } 522 523 /* returns ino associated with a cgroup */ 524 static inline ino_t cgroup_ino(struct cgroup *cgrp) 525 { 526 return cgrp->kn->ino; 527 } 528 529 /* cft/css accessors for cftype->write() operation */ 530 static inline struct cftype *of_cft(struct kernfs_open_file *of) 531 { 532 return of->kn->priv; 533 } 534 535 struct cgroup_subsys_state *of_css(struct kernfs_open_file *of); 536 537 /* 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 } 542 543 static inline struct cgroup_subsys_state *seq_css(struct seq_file *seq) 544 { 545 return of_css(seq->private); 546 } 547 548 /* 549 * Name / path handling functions. All are thin wrappers around the kernfs 550 * counterparts and can be called under any context. 551 */ 552 553 static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen) 554 { 555 return kernfs_name(cgrp->kn, buf, buflen); 556 } 557 558 static inline int cgroup_path(struct cgroup *cgrp, char *buf, size_t buflen) 559 { 560 return kernfs_path(cgrp->kn, buf, buflen); 561 } 562 563 static inline void pr_cont_cgroup_name(struct cgroup *cgrp) 564 { 565 pr_cont_kernfs_name(cgrp->kn); 566 } 567 568 static inline void pr_cont_cgroup_path(struct cgroup *cgrp) 569 { 570 pr_cont_kernfs_path(cgrp->kn); 571 } 572 573 static inline void cgroup_init_kthreadd(void) 574 { 575 /* 576 * kthreadd is inherited by all kthreads, keep it in the root so 577 * that the new kthreads are guaranteed to stay in the root until 578 * initialization is finished. 579 */ 580 current->no_cgroup_migration = 1; 581 } 582 583 static inline void cgroup_kthread_ready(void) 584 { 585 /* 586 * This kthread finished initialization. The creator should have 587 * set PF_NO_SETAFFINITY if this kthread should stay in the root. 588 */ 589 current->no_cgroup_migration = 0; 590 } 591 592 #else /* !CONFIG_CGROUPS */ 593 594 struct cgroup_subsys_state; 595 struct cgroup; 596 597 static inline void css_put(struct cgroup_subsys_state *css) {} 598 static inline int cgroup_attach_task_all(struct task_struct *from, 599 struct task_struct *t) { return 0; } 600 static inline int cgroupstats_build(struct cgroupstats *stats, 601 struct dentry *dentry) { return -EINVAL; } 602 603 static inline void cgroup_fork(struct task_struct *p) {} 604 static inline int cgroup_can_fork(struct task_struct *p) { return 0; } 605 static inline void cgroup_cancel_fork(struct task_struct *p) {} 606 static inline void cgroup_post_fork(struct task_struct *p) {} 607 static inline void cgroup_exit(struct task_struct *p) {} 608 static inline void cgroup_free(struct task_struct *p) {} 609 610 static inline int cgroup_init_early(void) { return 0; } 611 static inline int cgroup_init(void) { return 0; } 612 static inline void cgroup_init_kthreadd(void) {} 613 static inline void cgroup_kthread_ready(void) {} 614 615 static inline bool task_under_cgroup_hierarchy(struct task_struct *task, 616 struct cgroup *ancestor) 617 { 618 return true; 619 } 620 #endif /* !CONFIG_CGROUPS */ 621 622 /* 623 * sock->sk_cgrp_data handling. For more info, see sock_cgroup_data 624 * definition in cgroup-defs.h. 625 */ 626 #ifdef CONFIG_SOCK_CGROUP_DATA 627 628 #if defined(CONFIG_CGROUP_NET_PRIO) || defined(CONFIG_CGROUP_NET_CLASSID) 629 extern spinlock_t cgroup_sk_update_lock; 630 #endif 631 632 void cgroup_sk_alloc_disable(void); 633 void cgroup_sk_alloc(struct sock_cgroup_data *skcd); 634 void cgroup_sk_free(struct sock_cgroup_data *skcd); 635 636 static inline struct cgroup *sock_cgroup_ptr(struct sock_cgroup_data *skcd) 637 { 638 #if defined(CONFIG_CGROUP_NET_PRIO) || defined(CONFIG_CGROUP_NET_CLASSID) 639 unsigned long v; 640 641 /* 642 * @skcd->val is 64bit but the following is safe on 32bit too as we 643 * just need the lower ulong to be written and read atomically. 644 */ 645 v = READ_ONCE(skcd->val); 646 647 if (v & 1) 648 return &cgrp_dfl_root.cgrp; 649 650 return (struct cgroup *)(unsigned long)v ?: &cgrp_dfl_root.cgrp; 651 #else 652 return (struct cgroup *)(unsigned long)skcd->val; 653 #endif 654 } 655 656 #else /* CONFIG_CGROUP_DATA */ 657 658 static inline void cgroup_sk_alloc(struct sock_cgroup_data *skcd) {} 659 static inline void cgroup_sk_free(struct sock_cgroup_data *skcd) {} 660 661 #endif /* CONFIG_CGROUP_DATA */ 662 663 struct cgroup_namespace { 664 refcount_t count; 665 struct ns_common ns; 666 struct user_namespace *user_ns; 667 struct ucounts *ucounts; 668 struct css_set *root_cset; 669 }; 670 671 extern struct cgroup_namespace init_cgroup_ns; 672 673 #ifdef CONFIG_CGROUPS 674 675 void free_cgroup_ns(struct cgroup_namespace *ns); 676 677 struct cgroup_namespace *copy_cgroup_ns(unsigned long flags, 678 struct user_namespace *user_ns, 679 struct cgroup_namespace *old_ns); 680 681 int cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen, 682 struct cgroup_namespace *ns); 683 684 #else /* !CONFIG_CGROUPS */ 685 686 static inline void free_cgroup_ns(struct cgroup_namespace *ns) { } 687 static inline struct cgroup_namespace * 688 copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns, 689 struct cgroup_namespace *old_ns) 690 { 691 return old_ns; 692 } 693 694 #endif /* !CONFIG_CGROUPS */ 695 696 static inline void get_cgroup_ns(struct cgroup_namespace *ns) 697 { 698 if (ns) 699 refcount_inc(&ns->count); 700 } 701 702 static inline void put_cgroup_ns(struct cgroup_namespace *ns) 703 { 704 if (ns && refcount_dec_and_test(&ns->count)) 705 free_cgroup_ns(ns); 706 } 707 708 #endif /* _LINUX_CGROUP_H */ 709