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

source code of linux/include/linux/workqueue.h