1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * workqueue.h --- work queue handling for Linux.
4 */
5
6 #ifndef _LINUX_WORKQUEUE_H
7 #define _LINUX_WORKQUEUE_H
8
9 #include <linux/timer.h>
10 #include <linux/linkage.h>
11 #include <linux/bitops.h>
12 #include <linux/lockdep.h>
13 #include <linux/threads.h>
14 #include <linux/atomic.h>
15 #include <linux/cpumask_types.h>
16 #include <linux/rcupdate.h>
17 #include <linux/workqueue_types.h>
18 #include <linux/android_kabi.h>
19
20 /*
21 * The first word is the work queue pointer and the flags rolled into
22 * one
23 */
24 #define work_data_bits(work) ((unsigned long *)(&(work)->data))
25
26 enum work_bits {
27 WORK_STRUCT_PENDING_BIT = 0, /* work item is pending execution */
28 WORK_STRUCT_INACTIVE_BIT, /* work item is inactive */
29 WORK_STRUCT_PWQ_BIT, /* data points to pwq */
30 WORK_STRUCT_LINKED_BIT, /* next work is linked to this one */
31 #ifdef CONFIG_DEBUG_OBJECTS_WORK
32 WORK_STRUCT_STATIC_BIT, /* static initializer (debugobjects) */
33 #endif
34 WORK_STRUCT_FLAG_BITS,
35
36 /* color for workqueue flushing */
37 WORK_STRUCT_COLOR_SHIFT = WORK_STRUCT_FLAG_BITS,
38 WORK_STRUCT_COLOR_BITS = 4,
39
40 /*
41 * When WORK_STRUCT_PWQ is set, reserve 8 bits off of pwq pointer w/
42 * debugobjects turned off. This makes pwqs aligned to 256 bytes (512
43 * bytes w/ DEBUG_OBJECTS_WORK) and allows 16 workqueue flush colors.
44 *
45 * MSB
46 * [ pwq pointer ] [ flush color ] [ STRUCT flags ]
47 * 4 bits 4 or 5 bits
48 */
49 WORK_STRUCT_PWQ_SHIFT = WORK_STRUCT_COLOR_SHIFT + WORK_STRUCT_COLOR_BITS,
50
51 /*
52 * data contains off-queue information when !WORK_STRUCT_PWQ.
53 *
54 * MSB
55 * [ pool ID ] [ disable depth ] [ OFFQ flags ] [ STRUCT flags ]
56 * 16 bits 1 bit 4 or 5 bits
57 */
58 WORK_OFFQ_FLAG_SHIFT = WORK_STRUCT_FLAG_BITS,
59 WORK_OFFQ_BH_BIT = WORK_OFFQ_FLAG_SHIFT,
60 WORK_OFFQ_FLAG_END,
61 WORK_OFFQ_FLAG_BITS = WORK_OFFQ_FLAG_END - WORK_OFFQ_FLAG_SHIFT,
62
63 WORK_OFFQ_DISABLE_SHIFT = WORK_OFFQ_FLAG_SHIFT + WORK_OFFQ_FLAG_BITS,
64 WORK_OFFQ_DISABLE_BITS = 16,
65
66 /*
67 * When a work item is off queue, the high bits encode off-queue flags
68 * and the last pool it was on. Cap pool ID to 31 bits and use the
69 * highest number to indicate that no pool is associated.
70 */
71 WORK_OFFQ_POOL_SHIFT = WORK_OFFQ_DISABLE_SHIFT + WORK_OFFQ_DISABLE_BITS,
72 WORK_OFFQ_LEFT = BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT,
73 WORK_OFFQ_POOL_BITS = WORK_OFFQ_LEFT <= 31 ? WORK_OFFQ_LEFT : 31,
74 };
75
76 enum work_flags {
77 WORK_STRUCT_PENDING = 1 << WORK_STRUCT_PENDING_BIT,
78 WORK_STRUCT_INACTIVE = 1 << WORK_STRUCT_INACTIVE_BIT,
79 WORK_STRUCT_PWQ = 1 << WORK_STRUCT_PWQ_BIT,
80 WORK_STRUCT_LINKED = 1 << WORK_STRUCT_LINKED_BIT,
81 #ifdef CONFIG_DEBUG_OBJECTS_WORK
82 WORK_STRUCT_STATIC = 1 << WORK_STRUCT_STATIC_BIT,
83 #else
84 WORK_STRUCT_STATIC = 0,
85 #endif
86 };
87
88 enum wq_misc_consts {
89 WORK_NR_COLORS = (1 << WORK_STRUCT_COLOR_BITS),
90
91 /* not bound to any CPU, prefer the local CPU */
92 WORK_CPU_UNBOUND = NR_CPUS,
93
94 /* bit mask for work_busy() return values */
95 WORK_BUSY_PENDING = 1 << 0,
96 WORK_BUSY_RUNNING = 1 << 1,
97
98 /* maximum string length for set_worker_desc() */
99 WORKER_DESC_LEN = 32,
100 };
101
102 /* Convenience constants - of type 'unsigned long', not 'enum'! */
103 #define WORK_OFFQ_BH (1ul << WORK_OFFQ_BH_BIT)
104 #define WORK_OFFQ_FLAG_MASK (((1ul << WORK_OFFQ_FLAG_BITS) - 1) << WORK_OFFQ_FLAG_SHIFT)
105 #define WORK_OFFQ_DISABLE_MASK (((1ul << WORK_OFFQ_DISABLE_BITS) - 1) << WORK_OFFQ_DISABLE_SHIFT)
106 #define WORK_OFFQ_POOL_NONE ((1ul << WORK_OFFQ_POOL_BITS) - 1)
107 #define WORK_STRUCT_NO_POOL (WORK_OFFQ_POOL_NONE << WORK_OFFQ_POOL_SHIFT)
108 #define WORK_STRUCT_PWQ_MASK (~((1ul << WORK_STRUCT_PWQ_SHIFT) - 1))
109
110 #define WORK_DATA_INIT() ATOMIC_LONG_INIT((unsigned long)WORK_STRUCT_NO_POOL)
111 #define WORK_DATA_STATIC_INIT() \
112 ATOMIC_LONG_INIT((unsigned long)(WORK_STRUCT_NO_POOL | WORK_STRUCT_STATIC))
113
114 struct delayed_work {
115 struct work_struct work;
116 struct timer_list timer;
117
118 /* target workqueue and CPU ->timer uses to queue ->work */
119 struct workqueue_struct *wq;
120 int cpu;
121
122 ANDROID_KABI_RESERVE(1);
123 ANDROID_KABI_RESERVE(2);
124 };
125
126 struct rcu_work {
127 struct work_struct work;
128 struct rcu_head rcu;
129
130 /* target workqueue ->rcu uses to queue ->work */
131 struct workqueue_struct *wq;
132 };
133
134 enum wq_affn_scope {
135 WQ_AFFN_DFL, /* use system default */
136 WQ_AFFN_CPU, /* one pod per CPU */
137 WQ_AFFN_SMT, /* one pod poer SMT */
138 WQ_AFFN_CACHE, /* one pod per LLC */
139 WQ_AFFN_NUMA, /* one pod per NUMA node */
140 WQ_AFFN_SYSTEM, /* one pod across the whole system */
141
142 WQ_AFFN_NR_TYPES,
143 };
144
145 /**
146 * struct workqueue_attrs - A struct for workqueue attributes.
147 *
148 * This can be used to change attributes of an unbound workqueue.
149 */
150 struct workqueue_attrs {
151 /**
152 * @nice: nice level
153 */
154 int nice;
155
156 /**
157 * @cpumask: allowed CPUs
158 *
159 * Work items in this workqueue are affine to these CPUs and not allowed
160 * to execute on other CPUs. A pool serving a workqueue must have the
161 * same @cpumask.
162 */
163 cpumask_var_t cpumask;
164
165 /**
166 * @__pod_cpumask: internal attribute used to create per-pod pools
167 *
168 * Internal use only.
169 *
170 * Per-pod unbound worker pools are used to improve locality. Always a
171 * subset of ->cpumask. A workqueue can be associated with multiple
172 * worker pools with disjoint @__pod_cpumask's. Whether the enforcement
173 * of a pool's @__pod_cpumask is strict depends on @affn_strict.
174 */
175 cpumask_var_t __pod_cpumask;
176
177 /**
178 * @affn_strict: affinity scope is strict
179 *
180 * If clear, workqueue will make a best-effort attempt at starting the
181 * worker inside @__pod_cpumask but the scheduler is free to migrate it
182 * outside.
183 *
184 * If set, workers are only allowed to run inside @__pod_cpumask.
185 */
186 bool affn_strict;
187
188 /*
189 * Below fields aren't properties of a worker_pool. They only modify how
190 * :c:func:`apply_workqueue_attrs` select pools and thus don't
191 * participate in pool hash calculations or equality comparisons.
192 *
193 * If @affn_strict is set, @cpumask isn't a property of a worker_pool
194 * either.
195 */
196
197 /**
198 * @affn_scope: unbound CPU affinity scope
199 *
200 * CPU pods are used to improve execution locality of unbound work
201 * items. There are multiple pod types, one for each wq_affn_scope, and
202 * every CPU in the system belongs to one pod in every pod type. CPUs
203 * that belong to the same pod share the worker pool. For example,
204 * selecting %WQ_AFFN_NUMA makes the workqueue use a separate worker
205 * pool for each NUMA node.
206 */
207 enum wq_affn_scope affn_scope;
208
209 /**
210 * @ordered: work items must be executed one by one in queueing order
211 */
212 bool ordered;
213 };
214
to_delayed_work(struct work_struct * work)215 static inline struct delayed_work *to_delayed_work(struct work_struct *work)
216 {
217 return container_of(work, struct delayed_work, work);
218 }
219
to_rcu_work(struct work_struct * work)220 static inline struct rcu_work *to_rcu_work(struct work_struct *work)
221 {
222 return container_of(work, struct rcu_work, work);
223 }
224
225 struct execute_work {
226 struct work_struct work;
227 };
228
229 #ifdef CONFIG_LOCKDEP
230 /*
231 * NB: because we have to copy the lockdep_map, setting _key
232 * here is required, otherwise it could get initialised to the
233 * copy of the lockdep_map!
234 */
235 #define __WORK_INIT_LOCKDEP_MAP(n, k) \
236 .lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k),
237 #else
238 #define __WORK_INIT_LOCKDEP_MAP(n, k)
239 #endif
240
241 #define __WORK_INITIALIZER(n, f) { \
242 .data = WORK_DATA_STATIC_INIT(), \
243 .entry = { &(n).entry, &(n).entry }, \
244 .func = (f), \
245 __WORK_INIT_LOCKDEP_MAP(#n, &(n)) \
246 }
247
248 #define __DELAYED_WORK_INITIALIZER(n, f, tflags) { \
249 .work = __WORK_INITIALIZER((n).work, (f)), \
250 .timer = __TIMER_INITIALIZER(delayed_work_timer_fn,\
251 (tflags) | TIMER_IRQSAFE), \
252 }
253
254 #define DECLARE_WORK(n, f) \
255 struct work_struct n = __WORK_INITIALIZER(n, f)
256
257 #define DECLARE_DELAYED_WORK(n, f) \
258 struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, 0)
259
260 #define DECLARE_DEFERRABLE_WORK(n, f) \
261 struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, TIMER_DEFERRABLE)
262
263 #ifdef CONFIG_DEBUG_OBJECTS_WORK
264 extern void __init_work(struct work_struct *work, int onstack);
265 extern void destroy_work_on_stack(struct work_struct *work);
266 extern void destroy_delayed_work_on_stack(struct delayed_work *work);
work_static(struct work_struct * work)267 static inline unsigned int work_static(struct work_struct *work)
268 {
269 return *work_data_bits(work) & WORK_STRUCT_STATIC;
270 }
271 #else
__init_work(struct work_struct * work,int onstack)272 static inline void __init_work(struct work_struct *work, int onstack) { }
destroy_work_on_stack(struct work_struct * work)273 static inline void destroy_work_on_stack(struct work_struct *work) { }
destroy_delayed_work_on_stack(struct delayed_work * work)274 static inline void destroy_delayed_work_on_stack(struct delayed_work *work) { }
work_static(struct work_struct * work)275 static inline unsigned int work_static(struct work_struct *work) { return 0; }
276 #endif
277
278 /*
279 * initialize all of a work item in one go
280 *
281 * NOTE! No point in using "atomic_long_set()": using a direct
282 * assignment of the work data initializer allows the compiler
283 * to generate better code.
284 */
285 #ifdef CONFIG_LOCKDEP
286 #define __INIT_WORK_KEY(_work, _func, _onstack, _key) \
287 do { \
288 __init_work((_work), _onstack); \
289 (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
290 lockdep_init_map(&(_work)->lockdep_map, "(work_completion)"#_work, (_key), 0); \
291 INIT_LIST_HEAD(&(_work)->entry); \
292 (_work)->func = (_func); \
293 } while (0)
294 #else
295 #define __INIT_WORK_KEY(_work, _func, _onstack, _key) \
296 do { \
297 __init_work((_work), _onstack); \
298 (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
299 INIT_LIST_HEAD(&(_work)->entry); \
300 (_work)->func = (_func); \
301 } while (0)
302 #endif
303
304 #define __INIT_WORK(_work, _func, _onstack) \
305 do { \
306 static __maybe_unused struct lock_class_key __key; \
307 \
308 __INIT_WORK_KEY(_work, _func, _onstack, &__key); \
309 } while (0)
310
311 #define INIT_WORK(_work, _func) \
312 __INIT_WORK((_work), (_func), 0)
313
314 #define INIT_WORK_ONSTACK(_work, _func) \
315 __INIT_WORK((_work), (_func), 1)
316
317 #define INIT_WORK_ONSTACK_KEY(_work, _func, _key) \
318 __INIT_WORK_KEY((_work), (_func), 1, _key)
319
320 #define __INIT_DELAYED_WORK(_work, _func, _tflags) \
321 do { \
322 INIT_WORK(&(_work)->work, (_func)); \
323 __init_timer(&(_work)->timer, \
324 delayed_work_timer_fn, \
325 (_tflags) | TIMER_IRQSAFE); \
326 } while (0)
327
328 #define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags) \
329 do { \
330 INIT_WORK_ONSTACK(&(_work)->work, (_func)); \
331 __init_timer_on_stack(&(_work)->timer, \
332 delayed_work_timer_fn, \
333 (_tflags) | TIMER_IRQSAFE); \
334 } while (0)
335
336 #define INIT_DELAYED_WORK(_work, _func) \
337 __INIT_DELAYED_WORK(_work, _func, 0)
338
339 #define INIT_DELAYED_WORK_ONSTACK(_work, _func) \
340 __INIT_DELAYED_WORK_ONSTACK(_work, _func, 0)
341
342 #define INIT_DEFERRABLE_WORK(_work, _func) \
343 __INIT_DELAYED_WORK(_work, _func, TIMER_DEFERRABLE)
344
345 #define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func) \
346 __INIT_DELAYED_WORK_ONSTACK(_work, _func, TIMER_DEFERRABLE)
347
348 #define INIT_RCU_WORK(_work, _func) \
349 INIT_WORK(&(_work)->work, (_func))
350
351 #define INIT_RCU_WORK_ONSTACK(_work, _func) \
352 INIT_WORK_ONSTACK(&(_work)->work, (_func))
353
354 /**
355 * work_pending - Find out whether a work item is currently pending
356 * @work: The work item in question
357 */
358 #define work_pending(work) \
359 test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
360
361 /**
362 * delayed_work_pending - Find out whether a delayable work item is currently
363 * pending
364 * @w: The work item in question
365 */
366 #define delayed_work_pending(w) \
367 work_pending(&(w)->work)
368
369 /*
370 * Workqueue flags and constants. For details, please refer to
371 * Documentation/core-api/workqueue.rst.
372 */
373 enum wq_flags {
374 WQ_BH = 1 << 0, /* execute in bottom half (softirq) context */
375 WQ_UNBOUND = 1 << 1, /* not bound to any cpu */
376 WQ_FREEZABLE = 1 << 2, /* freeze during suspend */
377 WQ_MEM_RECLAIM = 1 << 3, /* may be used for memory reclaim */
378 WQ_HIGHPRI = 1 << 4, /* high priority */
379 WQ_CPU_INTENSIVE = 1 << 5, /* cpu intensive workqueue */
380 WQ_SYSFS = 1 << 6, /* visible in sysfs, see workqueue_sysfs_register() */
381
382 /*
383 * Per-cpu workqueues are generally preferred because they tend to
384 * show better performance thanks to cache locality. Per-cpu
385 * workqueues exclude the scheduler from choosing the CPU to
386 * execute the worker threads, which has an unfortunate side effect
387 * of increasing power consumption.
388 *
389 * The scheduler considers a CPU idle if it doesn't have any task
390 * to execute and tries to keep idle cores idle to conserve power;
391 * however, for example, a per-cpu work item scheduled from an
392 * interrupt handler on an idle CPU will force the scheduler to
393 * execute the work item on that CPU breaking the idleness, which in
394 * turn may lead to more scheduling choices which are sub-optimal
395 * in terms of power consumption.
396 *
397 * Workqueues marked with WQ_POWER_EFFICIENT are per-cpu by default
398 * but become unbound if workqueue.power_efficient kernel param is
399 * specified. Per-cpu workqueues which are identified to
400 * contribute significantly to power-consumption are identified and
401 * marked with this flag and enabling the power_efficient mode
402 * leads to noticeable power saving at the cost of small
403 * performance disadvantage.
404 *
405 * http://thread.gmane.org/gmane.linux.kernel/1480396
406 */
407 WQ_POWER_EFFICIENT = 1 << 7,
408
409 __WQ_DESTROYING = 1 << 15, /* internal: workqueue is destroying */
410 __WQ_DRAINING = 1 << 16, /* internal: workqueue is draining */
411 __WQ_ORDERED = 1 << 17, /* internal: workqueue is ordered */
412 __WQ_LEGACY = 1 << 18, /* internal: create*_workqueue() */
413
414 /* BH wq only allows the following flags */
415 __WQ_BH_ALLOWS = WQ_BH | WQ_HIGHPRI,
416 };
417
418 enum wq_consts {
419 WQ_MAX_ACTIVE = 512, /* I like 512, better ideas? */
420 WQ_UNBOUND_MAX_ACTIVE = WQ_MAX_ACTIVE,
421 WQ_DFL_ACTIVE = WQ_MAX_ACTIVE / 2,
422
423 /*
424 * Per-node default cap on min_active. Unless explicitly set, min_active
425 * is set to min(max_active, WQ_DFL_MIN_ACTIVE). For more details, see
426 * workqueue_struct->min_active definition.
427 */
428 WQ_DFL_MIN_ACTIVE = 8,
429 };
430
431 /*
432 * System-wide workqueues which are always present.
433 *
434 * system_wq is the one used by schedule[_delayed]_work[_on]().
435 * Multi-CPU multi-threaded. There are users which expect relatively
436 * short queue flush time. Don't queue works which can run for too
437 * long.
438 *
439 * system_highpri_wq is similar to system_wq but for work items which
440 * require WQ_HIGHPRI.
441 *
442 * system_long_wq is similar to system_wq but may host long running
443 * works. Queue flushing might take relatively long.
444 *
445 * system_unbound_wq is unbound workqueue. Workers are not bound to
446 * any specific CPU, not concurrency managed, and all queued works are
447 * executed immediately as long as max_active limit is not reached and
448 * resources are available.
449 *
450 * system_freezable_wq is equivalent to system_wq except that it's
451 * freezable.
452 *
453 * *_power_efficient_wq are inclined towards saving power and converted
454 * into WQ_UNBOUND variants if 'wq_power_efficient' is enabled; otherwise,
455 * they are same as their non-power-efficient counterparts - e.g.
456 * system_power_efficient_wq is identical to system_wq if
457 * 'wq_power_efficient' is disabled. See WQ_POWER_EFFICIENT for more info.
458 *
459 * system_bh[_highpri]_wq are convenience interface to softirq. BH work items
460 * are executed in the queueing CPU's BH context in the queueing order.
461 */
462 extern struct workqueue_struct *system_wq;
463 extern struct workqueue_struct *system_highpri_wq;
464 extern struct workqueue_struct *system_long_wq;
465 extern struct workqueue_struct *system_unbound_wq;
466 extern struct workqueue_struct *system_freezable_wq;
467 extern struct workqueue_struct *system_power_efficient_wq;
468 extern struct workqueue_struct *system_freezable_power_efficient_wq;
469 extern struct workqueue_struct *system_bh_wq;
470 extern struct workqueue_struct *system_bh_highpri_wq;
471
472 void workqueue_softirq_action(bool highpri);
473 void workqueue_softirq_dead(unsigned int cpu);
474
475 /**
476 * alloc_workqueue - allocate a workqueue
477 * @fmt: printf format for the name of the workqueue
478 * @flags: WQ_* flags
479 * @max_active: max in-flight work items, 0 for default
480 * @...: args for @fmt
481 *
482 * For a per-cpu workqueue, @max_active limits the number of in-flight work
483 * items for each CPU. e.g. @max_active of 1 indicates that each CPU can be
484 * executing at most one work item for the workqueue.
485 *
486 * For unbound workqueues, @max_active limits the number of in-flight work items
487 * for the whole system. e.g. @max_active of 16 indicates that that there can be
488 * at most 16 work items executing for the workqueue in the whole system.
489 *
490 * As sharing the same active counter for an unbound workqueue across multiple
491 * NUMA nodes can be expensive, @max_active is distributed to each NUMA node
492 * according to the proportion of the number of online CPUs and enforced
493 * independently.
494 *
495 * Depending on online CPU distribution, a node may end up with per-node
496 * max_active which is significantly lower than @max_active, which can lead to
497 * deadlocks if the per-node concurrency limit is lower than the maximum number
498 * of interdependent work items for the workqueue.
499 *
500 * To guarantee forward progress regardless of online CPU distribution, the
501 * concurrency limit on every node is guaranteed to be equal to or greater than
502 * min_active which is set to min(@max_active, %WQ_DFL_MIN_ACTIVE). This means
503 * that the sum of per-node max_active's may be larger than @max_active.
504 *
505 * For detailed information on %WQ_* flags, please refer to
506 * Documentation/core-api/workqueue.rst.
507 *
508 * RETURNS:
509 * Pointer to the allocated workqueue on success, %NULL on failure.
510 */
511 __printf(1, 4) struct workqueue_struct *
512 alloc_workqueue(const char *fmt, unsigned int flags, int max_active, ...);
513
514 #ifdef CONFIG_LOCKDEP
515 /**
516 * alloc_workqueue_lockdep_map - allocate a workqueue with user-defined lockdep_map
517 * @fmt: printf format for the name of the workqueue
518 * @flags: WQ_* flags
519 * @max_active: max in-flight work items, 0 for default
520 * @lockdep_map: user-defined lockdep_map
521 * @...: args for @fmt
522 *
523 * Same as alloc_workqueue but with the a user-define lockdep_map. Useful for
524 * workqueues created with the same purpose and to avoid leaking a lockdep_map
525 * on each workqueue creation.
526 *
527 * RETURNS:
528 * Pointer to the allocated workqueue on success, %NULL on failure.
529 */
530 __printf(1, 5) struct workqueue_struct *
531 alloc_workqueue_lockdep_map(const char *fmt, unsigned int flags, int max_active,
532 struct lockdep_map *lockdep_map, ...);
533
534 /**
535 * alloc_ordered_workqueue_lockdep_map - allocate an ordered workqueue with
536 * user-defined lockdep_map
537 *
538 * @fmt: printf format for the name of the workqueue
539 * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
540 * @lockdep_map: user-defined lockdep_map
541 * @args: args for @fmt
542 *
543 * Same as alloc_ordered_workqueue but with the a user-define lockdep_map.
544 * Useful for workqueues created with the same purpose and to avoid leaking a
545 * lockdep_map on each workqueue creation.
546 *
547 * RETURNS:
548 * Pointer to the allocated workqueue on success, %NULL on failure.
549 */
550 #define alloc_ordered_workqueue_lockdep_map(fmt, flags, lockdep_map, args...) \
551 alloc_workqueue_lockdep_map(fmt, WQ_UNBOUND | __WQ_ORDERED | (flags), \
552 1, lockdep_map, ##args)
553 #endif
554
555 /**
556 * alloc_ordered_workqueue - allocate an ordered workqueue
557 * @fmt: printf format for the name of the workqueue
558 * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
559 * @args: args for @fmt
560 *
561 * Allocate an ordered workqueue. An ordered workqueue executes at
562 * most one work item at any given time in the queued order. They are
563 * implemented as unbound workqueues with @max_active of one.
564 *
565 * RETURNS:
566 * Pointer to the allocated workqueue on success, %NULL on failure.
567 */
568 #define alloc_ordered_workqueue(fmt, flags, args...) \
569 alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | (flags), 1, ##args)
570
571 #define create_workqueue(name) \
572 alloc_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, 1, (name))
573 #define create_freezable_workqueue(name) \
574 alloc_workqueue("%s", __WQ_LEGACY | WQ_FREEZABLE | WQ_UNBOUND | \
575 WQ_MEM_RECLAIM, 1, (name))
576 #define create_singlethread_workqueue(name) \
577 alloc_ordered_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, name)
578
579 #define from_work(var, callback_work, work_fieldname) \
580 container_of(callback_work, typeof(*var), work_fieldname)
581
582 extern void destroy_workqueue(struct workqueue_struct *wq);
583
584 struct workqueue_attrs *alloc_workqueue_attrs(void);
585 void free_workqueue_attrs(struct workqueue_attrs *attrs);
586 int apply_workqueue_attrs(struct workqueue_struct *wq,
587 const struct workqueue_attrs *attrs);
588 int apply_workqueue_attrs_locked(struct workqueue_struct *wq,
589 const struct workqueue_attrs *attrs);
590 extern int workqueue_unbound_exclude_cpumask(cpumask_var_t cpumask);
591
592 extern bool queue_work_on(int cpu, struct workqueue_struct *wq,
593 struct work_struct *work);
594 extern bool queue_work_node(int node, struct workqueue_struct *wq,
595 struct work_struct *work);
596 extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
597 struct delayed_work *work, unsigned long delay);
598 extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
599 struct delayed_work *dwork, unsigned long delay);
600 extern bool queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork);
601
602 extern void __flush_workqueue(struct workqueue_struct *wq);
603 extern void drain_workqueue(struct workqueue_struct *wq);
604
605 extern int schedule_on_each_cpu(work_func_t func);
606
607 int execute_in_process_context(work_func_t fn, struct execute_work *);
608
609 extern bool flush_work(struct work_struct *work);
610 extern bool cancel_work(struct work_struct *work);
611 extern bool cancel_work_sync(struct work_struct *work);
612
613 extern bool flush_delayed_work(struct delayed_work *dwork);
614 extern bool cancel_delayed_work(struct delayed_work *dwork);
615 extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
616
617 extern bool disable_work(struct work_struct *work);
618 extern bool disable_work_sync(struct work_struct *work);
619 extern bool enable_work(struct work_struct *work);
620
621 extern bool disable_delayed_work(struct delayed_work *dwork);
622 extern bool disable_delayed_work_sync(struct delayed_work *dwork);
623 extern bool enable_delayed_work(struct delayed_work *dwork);
624
625 extern bool flush_rcu_work(struct rcu_work *rwork);
626
627 extern void workqueue_set_max_active(struct workqueue_struct *wq,
628 int max_active);
629 extern void workqueue_set_min_active(struct workqueue_struct *wq,
630 int min_active);
631 extern struct work_struct *current_work(void);
632 extern bool current_is_workqueue_rescuer(void);
633 extern bool workqueue_congested(int cpu, struct workqueue_struct *wq);
634 extern unsigned int work_busy(struct work_struct *work);
635 extern __printf(1, 2) void set_worker_desc(const char *fmt, ...);
636 extern void print_worker_info(const char *log_lvl, struct task_struct *task);
637 extern void show_all_workqueues(void);
638 extern void show_freezable_workqueues(void);
639 extern void show_one_workqueue(struct workqueue_struct *wq);
640 extern void wq_worker_comm(char *buf, size_t size, struct task_struct *task);
641
642 /**
643 * queue_work - queue work on a workqueue
644 * @wq: workqueue to use
645 * @work: work to queue
646 *
647 * Returns %false if @work was already on a queue, %true otherwise.
648 *
649 * We queue the work to the CPU on which it was submitted, but if the CPU dies
650 * it can be processed by another CPU.
651 *
652 * Memory-ordering properties: If it returns %true, guarantees that all stores
653 * preceding the call to queue_work() in the program order will be visible from
654 * the CPU which will execute @work by the time such work executes, e.g.,
655 *
656 * { x is initially 0 }
657 *
658 * CPU0 CPU1
659 *
660 * WRITE_ONCE(x, 1); [ @work is being executed ]
661 * r0 = queue_work(wq, work); r1 = READ_ONCE(x);
662 *
663 * Forbids: r0 == true && r1 == 0
664 */
queue_work(struct workqueue_struct * wq,struct work_struct * work)665 static inline bool queue_work(struct workqueue_struct *wq,
666 struct work_struct *work)
667 {
668 return queue_work_on(WORK_CPU_UNBOUND, wq, work);
669 }
670
671 /**
672 * queue_delayed_work - queue work on a workqueue after delay
673 * @wq: workqueue to use
674 * @dwork: delayable work to queue
675 * @delay: number of jiffies to wait before queueing
676 *
677 * Equivalent to queue_delayed_work_on() but tries to use the local CPU.
678 */
queue_delayed_work(struct workqueue_struct * wq,struct delayed_work * dwork,unsigned long delay)679 static inline bool queue_delayed_work(struct workqueue_struct *wq,
680 struct delayed_work *dwork,
681 unsigned long delay)
682 {
683 return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
684 }
685
686 /**
687 * mod_delayed_work - modify delay of or queue a delayed work
688 * @wq: workqueue to use
689 * @dwork: work to queue
690 * @delay: number of jiffies to wait before queueing
691 *
692 * mod_delayed_work_on() on local CPU.
693 */
mod_delayed_work(struct workqueue_struct * wq,struct delayed_work * dwork,unsigned long delay)694 static inline bool mod_delayed_work(struct workqueue_struct *wq,
695 struct delayed_work *dwork,
696 unsigned long delay)
697 {
698 return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
699 }
700
701 /**
702 * schedule_work_on - put work task on a specific cpu
703 * @cpu: cpu to put the work task on
704 * @work: job to be done
705 *
706 * This puts a job on a specific cpu
707 */
schedule_work_on(int cpu,struct work_struct * work)708 static inline bool schedule_work_on(int cpu, struct work_struct *work)
709 {
710 return queue_work_on(cpu, system_wq, work);
711 }
712
713 /**
714 * schedule_work - put work task in global workqueue
715 * @work: job to be done
716 *
717 * Returns %false if @work was already on the kernel-global workqueue and
718 * %true otherwise.
719 *
720 * This puts a job in the kernel-global workqueue if it was not already
721 * queued and leaves it in the same position on the kernel-global
722 * workqueue otherwise.
723 *
724 * Shares the same memory-ordering properties of queue_work(), cf. the
725 * DocBook header of queue_work().
726 */
schedule_work(struct work_struct * work)727 static inline bool schedule_work(struct work_struct *work)
728 {
729 return queue_work(system_wq, work);
730 }
731
732 /**
733 * enable_and_queue_work - Enable and queue a work item on a specific workqueue
734 * @wq: The target workqueue
735 * @work: The work item to be enabled and queued
736 *
737 * This function combines the operations of enable_work() and queue_work(),
738 * providing a convenient way to enable and queue a work item in a single call.
739 * It invokes enable_work() on @work and then queues it if the disable depth
740 * reached 0. Returns %true if the disable depth reached 0 and @work is queued,
741 * and %false otherwise.
742 *
743 * Note that @work is always queued when disable depth reaches zero. If the
744 * desired behavior is queueing only if certain events took place while @work is
745 * disabled, the user should implement the necessary state tracking and perform
746 * explicit conditional queueing after enable_work().
747 */
enable_and_queue_work(struct workqueue_struct * wq,struct work_struct * work)748 static inline bool enable_and_queue_work(struct workqueue_struct *wq,
749 struct work_struct *work)
750 {
751 if (enable_work(work)) {
752 queue_work(wq, work);
753 return true;
754 }
755 return false;
756 }
757
758 /*
759 * Detect attempt to flush system-wide workqueues at compile time when possible.
760 * Warn attempt to flush system-wide workqueues at runtime.
761 *
762 * See https://lkml.kernel.org/r/49925af7-78a8-a3dd-bce6-cfc02e1a9236@I-love.SAKURA.ne.jp
763 * for reasons and steps for converting system-wide workqueues into local workqueues.
764 */
765 extern void __warn_flushing_systemwide_wq(void)
766 __compiletime_warning("Please avoid flushing system-wide workqueues.");
767
768 /* Please stop using this function, for this function will be removed in near future. */
769 #define flush_scheduled_work() \
770 ({ \
771 __warn_flushing_systemwide_wq(); \
772 __flush_workqueue(system_wq); \
773 })
774
775 #define flush_workqueue(wq) \
776 ({ \
777 struct workqueue_struct *_wq = (wq); \
778 \
779 if ((__builtin_constant_p(_wq == system_wq) && \
780 _wq == system_wq) || \
781 (__builtin_constant_p(_wq == system_highpri_wq) && \
782 _wq == system_highpri_wq) || \
783 (__builtin_constant_p(_wq == system_long_wq) && \
784 _wq == system_long_wq) || \
785 (__builtin_constant_p(_wq == system_unbound_wq) && \
786 _wq == system_unbound_wq) || \
787 (__builtin_constant_p(_wq == system_freezable_wq) && \
788 _wq == system_freezable_wq) || \
789 (__builtin_constant_p(_wq == system_power_efficient_wq) && \
790 _wq == system_power_efficient_wq) || \
791 (__builtin_constant_p(_wq == system_freezable_power_efficient_wq) && \
792 _wq == system_freezable_power_efficient_wq)) \
793 __warn_flushing_systemwide_wq(); \
794 __flush_workqueue(_wq); \
795 })
796
797 /**
798 * schedule_delayed_work_on - queue work in global workqueue on CPU after delay
799 * @cpu: cpu to use
800 * @dwork: job to be done
801 * @delay: number of jiffies to wait
802 *
803 * After waiting for a given time this puts a job in the kernel-global
804 * workqueue on the specified CPU.
805 */
schedule_delayed_work_on(int cpu,struct delayed_work * dwork,unsigned long delay)806 static inline bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork,
807 unsigned long delay)
808 {
809 return queue_delayed_work_on(cpu, system_wq, dwork, delay);
810 }
811
812 /**
813 * schedule_delayed_work - put work task in global workqueue after delay
814 * @dwork: job to be done
815 * @delay: number of jiffies to wait or 0 for immediate execution
816 *
817 * After waiting for a given time this puts a job in the kernel-global
818 * workqueue.
819 */
schedule_delayed_work(struct delayed_work * dwork,unsigned long delay)820 static inline bool schedule_delayed_work(struct delayed_work *dwork,
821 unsigned long delay)
822 {
823 return queue_delayed_work(system_wq, dwork, delay);
824 }
825
826 #ifndef CONFIG_SMP
work_on_cpu(int cpu,long (* fn)(void *),void * arg)827 static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
828 {
829 return fn(arg);
830 }
work_on_cpu_safe(int cpu,long (* fn)(void *),void * arg)831 static inline long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg)
832 {
833 return fn(arg);
834 }
835 #else
836 long work_on_cpu_key(int cpu, long (*fn)(void *),
837 void *arg, struct lock_class_key *key);
838 /*
839 * A new key is defined for each caller to make sure the work
840 * associated with the function doesn't share its locking class.
841 */
842 #define work_on_cpu(_cpu, _fn, _arg) \
843 ({ \
844 static struct lock_class_key __key; \
845 \
846 work_on_cpu_key(_cpu, _fn, _arg, &__key); \
847 })
848
849 long work_on_cpu_safe_key(int cpu, long (*fn)(void *),
850 void *arg, struct lock_class_key *key);
851
852 /*
853 * A new key is defined for each caller to make sure the work
854 * associated with the function doesn't share its locking class.
855 */
856 #define work_on_cpu_safe(_cpu, _fn, _arg) \
857 ({ \
858 static struct lock_class_key __key; \
859 \
860 work_on_cpu_safe_key(_cpu, _fn, _arg, &__key); \
861 })
862 #endif /* CONFIG_SMP */
863
864 #ifdef CONFIG_FREEZER
865 extern void freeze_workqueues_begin(void);
866 extern bool freeze_workqueues_busy(void);
867 extern void thaw_workqueues(void);
868 #endif /* CONFIG_FREEZER */
869
870 #ifdef CONFIG_SYSFS
871 int workqueue_sysfs_register(struct workqueue_struct *wq);
872 #else /* CONFIG_SYSFS */
workqueue_sysfs_register(struct workqueue_struct * wq)873 static inline int workqueue_sysfs_register(struct workqueue_struct *wq)
874 { return 0; }
875 #endif /* CONFIG_SYSFS */
876
877 #ifdef CONFIG_WQ_WATCHDOG
878 void wq_watchdog_touch(int cpu);
879 #else /* CONFIG_WQ_WATCHDOG */
wq_watchdog_touch(int cpu)880 static inline void wq_watchdog_touch(int cpu) { }
881 #endif /* CONFIG_WQ_WATCHDOG */
882
883 #ifdef CONFIG_SMP
884 int workqueue_prepare_cpu(unsigned int cpu);
885 int workqueue_online_cpu(unsigned int cpu);
886 int workqueue_offline_cpu(unsigned int cpu);
887 #endif
888
889 void __init workqueue_init_early(void);
890 void __init workqueue_init(void);
891 void __init workqueue_init_topology(void);
892
893 #endif
894