Commit | Line | Data |
---|---|---|
b4a04ab7 TH |
1 | /* |
2 | * linux/cgroup-defs.h - basic definitions for cgroup | |
3 | * | |
4 | * This file provides basic type and interface. Include this file directly | |
5 | * only if necessary to avoid cyclic dependencies. | |
6 | */ | |
7 | #ifndef _LINUX_CGROUP_DEFS_H | |
8 | #define _LINUX_CGROUP_DEFS_H | |
9 | ||
10 | #include <linux/limits.h> | |
11 | #include <linux/list.h> | |
12 | #include <linux/idr.h> | |
13 | #include <linux/wait.h> | |
14 | #include <linux/mutex.h> | |
15 | #include <linux/rcupdate.h> | |
4b9502e6 | 16 | #include <linux/refcount.h> |
b4a04ab7 | 17 | #include <linux/percpu-refcount.h> |
7d7efec3 | 18 | #include <linux/percpu-rwsem.h> |
b4a04ab7 | 19 | #include <linux/workqueue.h> |
30070984 | 20 | #include <linux/bpf-cgroup.h> |
b4a04ab7 TH |
21 | |
22 | #ifdef CONFIG_CGROUPS | |
23 | ||
24 | struct cgroup; | |
25 | struct cgroup_root; | |
26 | struct cgroup_subsys; | |
27 | struct cgroup_taskset; | |
28 | struct kernfs_node; | |
29 | struct kernfs_ops; | |
30 | struct kernfs_open_file; | |
c80ef9e0 | 31 | struct seq_file; |
b4a04ab7 TH |
32 | |
33 | #define MAX_CGROUP_TYPE_NAMELEN 32 | |
34 | #define MAX_CGROUP_ROOT_NAMELEN 64 | |
35 | #define MAX_CFTYPE_NAME 64 | |
36 | ||
37 | /* define the enumeration of all cgroup subsystems */ | |
38 | #define SUBSYS(_x) _x ## _cgrp_id, | |
39 | enum cgroup_subsys_id { | |
40 | #include <linux/cgroup_subsys.h> | |
41 | CGROUP_SUBSYS_COUNT, | |
42 | }; | |
43 | #undef SUBSYS | |
44 | ||
45 | /* bits in struct cgroup_subsys_state flags field */ | |
46 | enum { | |
47 | CSS_NO_REF = (1 << 0), /* no reference counting for this css */ | |
48 | CSS_ONLINE = (1 << 1), /* between ->css_online() and ->css_offline() */ | |
49 | CSS_RELEASED = (1 << 2), /* refcnt reached zero, released */ | |
88cb04b9 | 50 | CSS_VISIBLE = (1 << 3), /* css is visible to userland */ |
33c35aa4 | 51 | CSS_DYING = (1 << 4), /* css is dying */ |
b4a04ab7 TH |
52 | }; |
53 | ||
54 | /* bits in struct cgroup flags field */ | |
55 | enum { | |
56 | /* Control Group requires release notifications to userspace */ | |
57 | CGRP_NOTIFY_ON_RELEASE, | |
58 | /* | |
59 | * Clone the parent's configuration when creating a new child | |
60 | * cpuset cgroup. For historical reasons, this option can be | |
61 | * specified at mount time and thus is implemented here. | |
62 | */ | |
63 | CGRP_CPUSET_CLONE_CHILDREN, | |
64 | }; | |
65 | ||
66 | /* cgroup_root->flags */ | |
67 | enum { | |
b4a04ab7 TH |
68 | CGRP_ROOT_NOPREFIX = (1 << 1), /* mounted subsystems have no named prefix */ |
69 | CGRP_ROOT_XATTR = (1 << 2), /* supports extended attributes */ | |
70 | }; | |
71 | ||
72 | /* cftype->flags */ | |
73 | enum { | |
74 | CFTYPE_ONLY_ON_ROOT = (1 << 0), /* only create on root cgrp */ | |
75 | CFTYPE_NOT_ON_ROOT = (1 << 1), /* don't create on root cgrp */ | |
76 | CFTYPE_NO_PREFIX = (1 << 3), /* (DON'T USE FOR NEW FILES) no subsys prefix */ | |
7dbdb199 | 77 | CFTYPE_WORLD_WRITABLE = (1 << 4), /* (DON'T USE FOR NEW FILES) S_IWUGO */ |
b4a04ab7 TH |
78 | |
79 | /* internal flags, do not use outside cgroup core proper */ | |
80 | __CFTYPE_ONLY_ON_DFL = (1 << 16), /* only on default hierarchy */ | |
81 | __CFTYPE_NOT_ON_DFL = (1 << 17), /* not on default hierarchy */ | |
82 | }; | |
83 | ||
6f60eade TH |
84 | /* |
85 | * cgroup_file is the handle for a file instance created in a cgroup which | |
86 | * is used, for example, to generate file changed notifications. This can | |
87 | * be obtained by setting cftype->file_offset. | |
88 | */ | |
89 | struct cgroup_file { | |
90 | /* do not access any fields from outside cgroup core */ | |
6f60eade TH |
91 | struct kernfs_node *kn; |
92 | }; | |
93 | ||
b4a04ab7 TH |
94 | /* |
95 | * Per-subsystem/per-cgroup state maintained by the system. This is the | |
96 | * fundamental structural building block that controllers deal with. | |
97 | * | |
98 | * Fields marked with "PI:" are public and immutable and may be accessed | |
99 | * directly without synchronization. | |
100 | */ | |
101 | struct cgroup_subsys_state { | |
102 | /* PI: the cgroup that this css is attached to */ | |
103 | struct cgroup *cgroup; | |
104 | ||
105 | /* PI: the cgroup subsystem that this css is attached to */ | |
106 | struct cgroup_subsys *ss; | |
107 | ||
108 | /* reference count - access via css_[try]get() and css_put() */ | |
109 | struct percpu_ref refcnt; | |
110 | ||
b4a04ab7 TH |
111 | /* siblings list anchored at the parent's ->children */ |
112 | struct list_head sibling; | |
113 | struct list_head children; | |
114 | ||
115 | /* | |
116 | * PI: Subsys-unique ID. 0 is unused and root is always 1. The | |
117 | * matching css can be looked up using css_from_id(). | |
118 | */ | |
119 | int id; | |
120 | ||
121 | unsigned int flags; | |
122 | ||
123 | /* | |
124 | * Monotonically increasing unique serial number which defines a | |
125 | * uniform order among all csses. It's guaranteed that all | |
126 | * ->children lists are in the ascending order of ->serial_nr and | |
127 | * used to allow interrupting and resuming iterations. | |
128 | */ | |
129 | u64 serial_nr; | |
130 | ||
aa226ff4 TH |
131 | /* |
132 | * Incremented by online self and children. Used to guarantee that | |
133 | * parents are not offlined before their children. | |
134 | */ | |
135 | atomic_t online_cnt; | |
136 | ||
b4a04ab7 TH |
137 | /* percpu_ref killing and RCU release */ |
138 | struct rcu_head rcu_head; | |
139 | struct work_struct destroy_work; | |
b8b1a2e5 TP |
140 | |
141 | /* | |
142 | * PI: the parent css. Placed here for cache proximity to following | |
143 | * fields of the containing structure. | |
144 | */ | |
145 | struct cgroup_subsys_state *parent; | |
b4a04ab7 TH |
146 | }; |
147 | ||
148 | /* | |
149 | * A css_set is a structure holding pointers to a set of | |
150 | * cgroup_subsys_state objects. This saves space in the task struct | |
151 | * object and speeds up fork()/exit(), since a single inc/dec and a | |
152 | * list_add()/del() can bump the reference count on the entire cgroup | |
153 | * set for a task. | |
154 | */ | |
155 | struct css_set { | |
b4a04ab7 | 156 | /* |
5f617ebb TH |
157 | * Set of subsystem states, one for each subsystem. This array is |
158 | * immutable after creation apart from the init_css_set during | |
159 | * subsystem registration (at boot time). | |
b4a04ab7 | 160 | */ |
5f617ebb TH |
161 | struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; |
162 | ||
163 | /* reference count */ | |
4b9502e6 | 164 | refcount_t refcount; |
5f617ebb TH |
165 | |
166 | /* the default cgroup associated with this css_set */ | |
167 | struct cgroup *dfl_cgrp; | |
b4a04ab7 TH |
168 | |
169 | /* | |
170 | * Lists running through all tasks using this cgroup group. | |
171 | * mg_tasks lists tasks which belong to this cset but are in the | |
172 | * process of being migrated out or in. Protected by | |
173 | * css_set_rwsem, but, during migration, once tasks are moved to | |
174 | * mg_tasks, it can be read safely while holding cgroup_mutex. | |
175 | */ | |
176 | struct list_head tasks; | |
177 | struct list_head mg_tasks; | |
178 | ||
5f617ebb TH |
179 | /* all css_task_iters currently walking this cset */ |
180 | struct list_head task_iters; | |
181 | ||
b4a04ab7 | 182 | /* |
5f617ebb TH |
183 | * On the default hierarhcy, ->subsys[ssid] may point to a css |
184 | * attached to an ancestor instead of the cgroup this css_set is | |
185 | * associated with. The following node is anchored at | |
186 | * ->subsys[ssid]->cgroup->e_csets[ssid] and provides a way to | |
187 | * iterate through all css's attached to a given cgroup. | |
b4a04ab7 | 188 | */ |
5f617ebb | 189 | struct list_head e_cset_node[CGROUP_SUBSYS_COUNT]; |
b4a04ab7 | 190 | |
5f617ebb TH |
191 | /* |
192 | * List running through all cgroup groups in the same hash | |
193 | * slot. Protected by css_set_lock | |
194 | */ | |
195 | struct hlist_node hlist; | |
b4a04ab7 TH |
196 | |
197 | /* | |
5f617ebb TH |
198 | * List of cgrp_cset_links pointing at cgroups referenced from this |
199 | * css_set. Protected by css_set_lock. | |
b4a04ab7 | 200 | */ |
5f617ebb | 201 | struct list_head cgrp_links; |
b4a04ab7 TH |
202 | |
203 | /* | |
204 | * List of csets participating in the on-going migration either as | |
205 | * source or destination. Protected by cgroup_mutex. | |
206 | */ | |
207 | struct list_head mg_preload_node; | |
208 | struct list_head mg_node; | |
209 | ||
210 | /* | |
211 | * If this cset is acting as the source of migration the following | |
e4857982 TH |
212 | * two fields are set. mg_src_cgrp and mg_dst_cgrp are |
213 | * respectively the source and destination cgroups of the on-going | |
214 | * migration. mg_dst_cset is the destination cset the target tasks | |
215 | * on this cset should be migrated to. Protected by cgroup_mutex. | |
b4a04ab7 TH |
216 | */ |
217 | struct cgroup *mg_src_cgrp; | |
e4857982 | 218 | struct cgroup *mg_dst_cgrp; |
b4a04ab7 TH |
219 | struct css_set *mg_dst_cset; |
220 | ||
2b021cbf TH |
221 | /* dead and being drained, ignore for migration */ |
222 | bool dead; | |
223 | ||
b4a04ab7 TH |
224 | /* For RCU-protected deletion */ |
225 | struct rcu_head rcu_head; | |
226 | }; | |
227 | ||
228 | struct cgroup { | |
229 | /* self css with NULL ->ss, points back to this cgroup */ | |
230 | struct cgroup_subsys_state self; | |
231 | ||
232 | unsigned long flags; /* "unsigned long" so bitops work */ | |
233 | ||
234 | /* | |
235 | * idr allocated in-hierarchy ID. | |
236 | * | |
237 | * ID 0 is not used, the ID of the root cgroup is always 1, and a | |
238 | * new cgroup will be assigned with a smallest available ID. | |
239 | * | |
240 | * Allocating/Removing ID must be protected by cgroup_mutex. | |
241 | */ | |
242 | int id; | |
243 | ||
b11cfb58 TH |
244 | /* |
245 | * The depth this cgroup is at. The root is at depth zero and each | |
246 | * step down the hierarchy increments the level. This along with | |
247 | * ancestor_ids[] can determine whether a given cgroup is a | |
248 | * descendant of another without traversing the hierarchy. | |
249 | */ | |
250 | int level; | |
251 | ||
b4a04ab7 | 252 | /* |
0de0942d TH |
253 | * Each non-empty css_set associated with this cgroup contributes |
254 | * one to populated_cnt. All children with non-zero popuplated_cnt | |
255 | * of their own contribute one. The count is zero iff there's no | |
256 | * task in this cgroup or its subtree. | |
b4a04ab7 TH |
257 | */ |
258 | int populated_cnt; | |
259 | ||
260 | struct kernfs_node *kn; /* cgroup kernfs entry */ | |
6f60eade TH |
261 | struct cgroup_file procs_file; /* handle for "cgroup.procs" */ |
262 | struct cgroup_file events_file; /* handle for "cgroup.events" */ | |
b4a04ab7 TH |
263 | |
264 | /* | |
265 | * The bitmask of subsystems enabled on the child cgroups. | |
266 | * ->subtree_control is the one configured through | |
8699b776 TH |
267 | * "cgroup.subtree_control" while ->child_ss_mask is the effective |
268 | * one which may have more subsystems enabled. Controller knobs | |
269 | * are made available iff it's enabled in ->subtree_control. | |
b4a04ab7 | 270 | */ |
6e5c8307 TH |
271 | u16 subtree_control; |
272 | u16 subtree_ss_mask; | |
15a27c36 TH |
273 | u16 old_subtree_control; |
274 | u16 old_subtree_ss_mask; | |
b4a04ab7 TH |
275 | |
276 | /* Private pointers for each registered subsystem */ | |
277 | struct cgroup_subsys_state __rcu *subsys[CGROUP_SUBSYS_COUNT]; | |
278 | ||
279 | struct cgroup_root *root; | |
280 | ||
281 | /* | |
282 | * List of cgrp_cset_links pointing at css_sets with tasks in this | |
283 | * cgroup. Protected by css_set_lock. | |
284 | */ | |
285 | struct list_head cset_links; | |
286 | ||
287 | /* | |
288 | * On the default hierarchy, a css_set for a cgroup with some | |
289 | * susbsys disabled will point to css's which are associated with | |
290 | * the closest ancestor which has the subsys enabled. The | |
291 | * following lists all css_sets which point to this cgroup's css | |
292 | * for the given subsystem. | |
293 | */ | |
294 | struct list_head e_csets[CGROUP_SUBSYS_COUNT]; | |
295 | ||
296 | /* | |
297 | * list of pidlists, up to two for each namespace (one for procs, one | |
298 | * for tasks); created on demand. | |
299 | */ | |
300 | struct list_head pidlists; | |
301 | struct mutex pidlist_mutex; | |
302 | ||
303 | /* used to wait for offlining of csses */ | |
304 | wait_queue_head_t offline_waitq; | |
305 | ||
306 | /* used to schedule release agent */ | |
307 | struct work_struct release_agent_work; | |
b11cfb58 | 308 | |
30070984 DM |
309 | /* used to store eBPF programs */ |
310 | struct cgroup_bpf bpf; | |
311 | ||
b11cfb58 TH |
312 | /* ids of the ancestors at each level including self */ |
313 | int ancestor_ids[]; | |
b4a04ab7 TH |
314 | }; |
315 | ||
316 | /* | |
317 | * A cgroup_root represents the root of a cgroup hierarchy, and may be | |
318 | * associated with a kernfs_root to form an active hierarchy. This is | |
319 | * internal to cgroup core. Don't access directly from controllers. | |
320 | */ | |
321 | struct cgroup_root { | |
322 | struct kernfs_root *kf_root; | |
323 | ||
324 | /* The bitmask of subsystems attached to this hierarchy */ | |
325 | unsigned int subsys_mask; | |
326 | ||
327 | /* Unique id for this hierarchy. */ | |
328 | int hierarchy_id; | |
329 | ||
330 | /* The root cgroup. Root is destroyed on its release. */ | |
331 | struct cgroup cgrp; | |
332 | ||
b11cfb58 TH |
333 | /* for cgrp->ancestor_ids[0] */ |
334 | int cgrp_ancestor_id_storage; | |
335 | ||
b4a04ab7 TH |
336 | /* Number of cgroups in the hierarchy, used only for /proc/cgroups */ |
337 | atomic_t nr_cgrps; | |
338 | ||
339 | /* A list running through the active hierarchies */ | |
340 | struct list_head root_list; | |
341 | ||
342 | /* Hierarchy-specific flags */ | |
343 | unsigned int flags; | |
344 | ||
345 | /* IDs for cgroups in this hierarchy */ | |
346 | struct idr cgroup_idr; | |
347 | ||
348 | /* The path to use for release notifications. */ | |
349 | char release_agent_path[PATH_MAX]; | |
350 | ||
351 | /* The name for this hierarchy - may be empty */ | |
352 | char name[MAX_CGROUP_ROOT_NAMELEN]; | |
353 | }; | |
354 | ||
355 | /* | |
356 | * struct cftype: handler definitions for cgroup control files | |
357 | * | |
358 | * When reading/writing to a file: | |
359 | * - the cgroup to use is file->f_path.dentry->d_parent->d_fsdata | |
360 | * - the 'cftype' of the file is file->f_path.dentry->d_fsdata | |
361 | */ | |
362 | struct cftype { | |
363 | /* | |
364 | * By convention, the name should begin with the name of the | |
365 | * subsystem, followed by a period. Zero length string indicates | |
366 | * end of cftype array. | |
367 | */ | |
368 | char name[MAX_CFTYPE_NAME]; | |
731a981e | 369 | unsigned long private; |
b4a04ab7 TH |
370 | |
371 | /* | |
372 | * The maximum length of string, excluding trailing nul, that can | |
373 | * be passed to write. If < PAGE_SIZE-1, PAGE_SIZE-1 is assumed. | |
374 | */ | |
375 | size_t max_write_len; | |
376 | ||
377 | /* CFTYPE_* flags */ | |
378 | unsigned int flags; | |
379 | ||
6f60eade TH |
380 | /* |
381 | * If non-zero, should contain the offset from the start of css to | |
382 | * a struct cgroup_file field. cgroup will record the handle of | |
383 | * the created file into it. The recorded handle can be used as | |
384 | * long as the containing css remains accessible. | |
385 | */ | |
386 | unsigned int file_offset; | |
387 | ||
b4a04ab7 TH |
388 | /* |
389 | * Fields used for internal bookkeeping. Initialized automatically | |
390 | * during registration. | |
391 | */ | |
392 | struct cgroup_subsys *ss; /* NULL for cgroup core files */ | |
393 | struct list_head node; /* anchored at ss->cfts */ | |
394 | struct kernfs_ops *kf_ops; | |
395 | ||
e90cbebc TH |
396 | int (*open)(struct kernfs_open_file *of); |
397 | void (*release)(struct kernfs_open_file *of); | |
398 | ||
b4a04ab7 TH |
399 | /* |
400 | * read_u64() is a shortcut for the common case of returning a | |
401 | * single integer. Use it in place of read() | |
402 | */ | |
403 | u64 (*read_u64)(struct cgroup_subsys_state *css, struct cftype *cft); | |
404 | /* | |
405 | * read_s64() is a signed version of read_u64() | |
406 | */ | |
407 | s64 (*read_s64)(struct cgroup_subsys_state *css, struct cftype *cft); | |
408 | ||
409 | /* generic seq_file read interface */ | |
410 | int (*seq_show)(struct seq_file *sf, void *v); | |
411 | ||
412 | /* optional ops, implement all or none */ | |
413 | void *(*seq_start)(struct seq_file *sf, loff_t *ppos); | |
414 | void *(*seq_next)(struct seq_file *sf, void *v, loff_t *ppos); | |
415 | void (*seq_stop)(struct seq_file *sf, void *v); | |
416 | ||
417 | /* | |
418 | * write_u64() is a shortcut for the common case of accepting | |
419 | * a single integer (as parsed by simple_strtoull) from | |
420 | * userspace. Use in place of write(); return 0 or error. | |
421 | */ | |
422 | int (*write_u64)(struct cgroup_subsys_state *css, struct cftype *cft, | |
423 | u64 val); | |
424 | /* | |
425 | * write_s64() is a signed version of write_u64() | |
426 | */ | |
427 | int (*write_s64)(struct cgroup_subsys_state *css, struct cftype *cft, | |
428 | s64 val); | |
429 | ||
430 | /* | |
431 | * write() is the generic write callback which maps directly to | |
432 | * kernfs write operation and overrides all other operations. | |
433 | * Maximum write size is determined by ->max_write_len. Use | |
434 | * of_css/cft() to access the associated css and cft. | |
435 | */ | |
436 | ssize_t (*write)(struct kernfs_open_file *of, | |
437 | char *buf, size_t nbytes, loff_t off); | |
438 | ||
439 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
440 | struct lock_class_key lockdep_key; | |
441 | #endif | |
442 | }; | |
443 | ||
444 | /* | |
445 | * Control Group subsystem type. | |
446 | * See Documentation/cgroups/cgroups.txt for details | |
447 | */ | |
448 | struct cgroup_subsys { | |
449 | struct cgroup_subsys_state *(*css_alloc)(struct cgroup_subsys_state *parent_css); | |
450 | int (*css_online)(struct cgroup_subsys_state *css); | |
451 | void (*css_offline)(struct cgroup_subsys_state *css); | |
452 | void (*css_released)(struct cgroup_subsys_state *css); | |
453 | void (*css_free)(struct cgroup_subsys_state *css); | |
454 | void (*css_reset)(struct cgroup_subsys_state *css); | |
b4a04ab7 | 455 | |
1f7dd3e5 TH |
456 | int (*can_attach)(struct cgroup_taskset *tset); |
457 | void (*cancel_attach)(struct cgroup_taskset *tset); | |
458 | void (*attach)(struct cgroup_taskset *tset); | |
5cf1cacb | 459 | void (*post_attach)(void); |
b53202e6 ON |
460 | int (*can_fork)(struct task_struct *task); |
461 | void (*cancel_fork)(struct task_struct *task); | |
462 | void (*fork)(struct task_struct *task); | |
2e91fa7f | 463 | void (*exit)(struct task_struct *task); |
afcf6c8b | 464 | void (*free)(struct task_struct *task); |
b4a04ab7 TH |
465 | void (*bind)(struct cgroup_subsys_state *root_css); |
466 | ||
b38e42e9 | 467 | bool early_init:1; |
b4a04ab7 | 468 | |
f6d635ad TH |
469 | /* |
470 | * If %true, the controller, on the default hierarchy, doesn't show | |
471 | * up in "cgroup.controllers" or "cgroup.subtree_control", is | |
472 | * implicitly enabled on all cgroups on the default hierarchy, and | |
473 | * bypasses the "no internal process" constraint. This is for | |
474 | * utility type controllers which is transparent to userland. | |
475 | * | |
476 | * An implicit controller can be stolen from the default hierarchy | |
477 | * anytime and thus must be okay with offline csses from previous | |
478 | * hierarchies coexisting with csses for the current one. | |
479 | */ | |
480 | bool implicit_on_dfl:1; | |
481 | ||
b4a04ab7 TH |
482 | /* |
483 | * If %false, this subsystem is properly hierarchical - | |
484 | * configuration, resource accounting and restriction on a parent | |
485 | * cgroup cover those of its children. If %true, hierarchy support | |
486 | * is broken in some ways - some subsystems ignore hierarchy | |
487 | * completely while others are only implemented half-way. | |
488 | * | |
489 | * It's now disallowed to create nested cgroups if the subsystem is | |
490 | * broken and cgroup core will emit a warning message on such | |
491 | * cases. Eventually, all subsystems will be made properly | |
492 | * hierarchical and this will go away. | |
493 | */ | |
b38e42e9 TH |
494 | bool broken_hierarchy:1; |
495 | bool warned_broken_hierarchy:1; | |
b4a04ab7 TH |
496 | |
497 | /* the following two fields are initialized automtically during boot */ | |
498 | int id; | |
499 | const char *name; | |
500 | ||
3e1d2eed TH |
501 | /* optional, initialized automatically during boot if not set */ |
502 | const char *legacy_name; | |
503 | ||
b4a04ab7 TH |
504 | /* link to parent, protected by cgroup_lock() */ |
505 | struct cgroup_root *root; | |
506 | ||
507 | /* idr for css->id */ | |
508 | struct idr css_idr; | |
509 | ||
510 | /* | |
511 | * List of cftypes. Each entry is the first entry of an array | |
512 | * terminated by zero length name. | |
513 | */ | |
514 | struct list_head cfts; | |
515 | ||
516 | /* | |
517 | * Base cftypes which are automatically registered. The two can | |
518 | * point to the same array. | |
519 | */ | |
520 | struct cftype *dfl_cftypes; /* for the default hierarchy */ | |
521 | struct cftype *legacy_cftypes; /* for the legacy hierarchies */ | |
522 | ||
523 | /* | |
524 | * A subsystem may depend on other subsystems. When such subsystem | |
525 | * is enabled on a cgroup, the depended-upon subsystems are enabled | |
526 | * together if available. Subsystems enabled due to dependency are | |
527 | * not visible to userland until explicitly enabled. The following | |
528 | * specifies the mask of subsystems that this one depends on. | |
529 | */ | |
530 | unsigned int depends_on; | |
531 | }; | |
532 | ||
1ed13287 TH |
533 | extern struct percpu_rw_semaphore cgroup_threadgroup_rwsem; |
534 | ||
535 | /** | |
536 | * cgroup_threadgroup_change_begin - threadgroup exclusion for cgroups | |
537 | * @tsk: target task | |
538 | * | |
780de9dd IM |
539 | * Allows cgroup operations to synchronize against threadgroup changes |
540 | * using a percpu_rw_semaphore. | |
1ed13287 TH |
541 | */ |
542 | static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk) | |
543 | { | |
544 | percpu_down_read(&cgroup_threadgroup_rwsem); | |
545 | } | |
546 | ||
547 | /** | |
548 | * cgroup_threadgroup_change_end - threadgroup exclusion for cgroups | |
549 | * @tsk: target task | |
550 | * | |
780de9dd | 551 | * Counterpart of cgroup_threadcgroup_change_begin(). |
1ed13287 TH |
552 | */ |
553 | static inline void cgroup_threadgroup_change_end(struct task_struct *tsk) | |
554 | { | |
555 | percpu_up_read(&cgroup_threadgroup_rwsem); | |
556 | } | |
7d7efec3 TH |
557 | |
558 | #else /* CONFIG_CGROUPS */ | |
559 | ||
cb4a3167 AS |
560 | #define CGROUP_SUBSYS_COUNT 0 |
561 | ||
780de9dd IM |
562 | static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk) |
563 | { | |
564 | might_sleep(); | |
565 | } | |
566 | ||
7d7efec3 TH |
567 | static inline void cgroup_threadgroup_change_end(struct task_struct *tsk) {} |
568 | ||
b4a04ab7 | 569 | #endif /* CONFIG_CGROUPS */ |
7d7efec3 | 570 | |
2a56a1fe TH |
571 | #ifdef CONFIG_SOCK_CGROUP_DATA |
572 | ||
bd1060a1 TH |
573 | /* |
574 | * sock_cgroup_data is embedded at sock->sk_cgrp_data and contains | |
575 | * per-socket cgroup information except for memcg association. | |
576 | * | |
577 | * On legacy hierarchies, net_prio and net_cls controllers directly set | |
578 | * attributes on each sock which can then be tested by the network layer. | |
579 | * On the default hierarchy, each sock is associated with the cgroup it was | |
580 | * created in and the networking layer can match the cgroup directly. | |
581 | * | |
582 | * To avoid carrying all three cgroup related fields separately in sock, | |
583 | * sock_cgroup_data overloads (prioidx, classid) and the cgroup pointer. | |
584 | * On boot, sock_cgroup_data records the cgroup that the sock was created | |
585 | * in so that cgroup2 matches can be made; however, once either net_prio or | |
586 | * net_cls starts being used, the area is overriden to carry prioidx and/or | |
587 | * classid. The two modes are distinguished by whether the lowest bit is | |
588 | * set. Clear bit indicates cgroup pointer while set bit prioidx and | |
589 | * classid. | |
590 | * | |
591 | * While userland may start using net_prio or net_cls at any time, once | |
592 | * either is used, cgroup2 matching no longer works. There is no reason to | |
593 | * mix the two and this is in line with how legacy and v2 compatibility is | |
594 | * handled. On mode switch, cgroup references which are already being | |
595 | * pointed to by socks may be leaked. While this can be remedied by adding | |
596 | * synchronization around sock_cgroup_data, given that the number of leaked | |
597 | * cgroups is bound and highly unlikely to be high, this seems to be the | |
598 | * better trade-off. | |
599 | */ | |
2a56a1fe | 600 | struct sock_cgroup_data { |
bd1060a1 TH |
601 | union { |
602 | #ifdef __LITTLE_ENDIAN | |
603 | struct { | |
604 | u8 is_data; | |
605 | u8 padding; | |
606 | u16 prioidx; | |
607 | u32 classid; | |
608 | } __packed; | |
609 | #else | |
610 | struct { | |
611 | u32 classid; | |
612 | u16 prioidx; | |
613 | u8 padding; | |
614 | u8 is_data; | |
615 | } __packed; | |
616 | #endif | |
617 | u64 val; | |
618 | }; | |
2a56a1fe TH |
619 | }; |
620 | ||
bd1060a1 TH |
621 | /* |
622 | * There's a theoretical window where the following accessors race with | |
623 | * updaters and return part of the previous pointer as the prioidx or | |
624 | * classid. Such races are short-lived and the result isn't critical. | |
625 | */ | |
2a56a1fe TH |
626 | static inline u16 sock_cgroup_prioidx(struct sock_cgroup_data *skcd) |
627 | { | |
bd1060a1 TH |
628 | /* fallback to 1 which is always the ID of the root cgroup */ |
629 | return (skcd->is_data & 1) ? skcd->prioidx : 1; | |
2a56a1fe TH |
630 | } |
631 | ||
632 | static inline u32 sock_cgroup_classid(struct sock_cgroup_data *skcd) | |
633 | { | |
bd1060a1 TH |
634 | /* fallback to 0 which is the unconfigured default classid */ |
635 | return (skcd->is_data & 1) ? skcd->classid : 0; | |
2a56a1fe TH |
636 | } |
637 | ||
bd1060a1 TH |
638 | /* |
639 | * If invoked concurrently, the updaters may clobber each other. The | |
640 | * caller is responsible for synchronization. | |
641 | */ | |
2a56a1fe TH |
642 | static inline void sock_cgroup_set_prioidx(struct sock_cgroup_data *skcd, |
643 | u16 prioidx) | |
644 | { | |
ad2c8c73 | 645 | struct sock_cgroup_data skcd_buf = {{ .val = READ_ONCE(skcd->val) }}; |
bd1060a1 TH |
646 | |
647 | if (sock_cgroup_prioidx(&skcd_buf) == prioidx) | |
648 | return; | |
649 | ||
650 | if (!(skcd_buf.is_data & 1)) { | |
651 | skcd_buf.val = 0; | |
652 | skcd_buf.is_data = 1; | |
653 | } | |
654 | ||
655 | skcd_buf.prioidx = prioidx; | |
656 | WRITE_ONCE(skcd->val, skcd_buf.val); /* see sock_cgroup_ptr() */ | |
2a56a1fe TH |
657 | } |
658 | ||
659 | static inline void sock_cgroup_set_classid(struct sock_cgroup_data *skcd, | |
660 | u32 classid) | |
661 | { | |
ad2c8c73 | 662 | struct sock_cgroup_data skcd_buf = {{ .val = READ_ONCE(skcd->val) }}; |
bd1060a1 TH |
663 | |
664 | if (sock_cgroup_classid(&skcd_buf) == classid) | |
665 | return; | |
666 | ||
667 | if (!(skcd_buf.is_data & 1)) { | |
668 | skcd_buf.val = 0; | |
669 | skcd_buf.is_data = 1; | |
670 | } | |
671 | ||
672 | skcd_buf.classid = classid; | |
673 | WRITE_ONCE(skcd->val, skcd_buf.val); /* see sock_cgroup_ptr() */ | |
2a56a1fe TH |
674 | } |
675 | ||
676 | #else /* CONFIG_SOCK_CGROUP_DATA */ | |
677 | ||
678 | struct sock_cgroup_data { | |
679 | }; | |
680 | ||
681 | #endif /* CONFIG_SOCK_CGROUP_DATA */ | |
682 | ||
b4a04ab7 | 683 | #endif /* _LINUX_CGROUP_DEFS_H */ |