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 #include <linux/android_kabi.h>
18
19 struct workqueue_struct;
20
21 struct work_struct;
22 typedef void (*work_func_t)(struct work_struct *work);
23 void delayed_work_timer_fn(struct timer_list *t);
24
25 /*
26 * The first word is the work queue pointer and the flags rolled into
27 * one
28 */
29 #define work_data_bits(work) ((unsigned long *)(&(work)->data))
30
31 enum {
32 WORK_STRUCT_PENDING_BIT = 0, /* work item is pending execution */
33 WORK_STRUCT_INACTIVE_BIT= 1, /* work item is inactive */
34 WORK_STRUCT_PWQ_BIT = 2, /* data points to pwq */
35 WORK_STRUCT_LINKED_BIT = 3, /* next work is linked to this one */
36 #ifdef CONFIG_DEBUG_OBJECTS_WORK
37 WORK_STRUCT_STATIC_BIT = 4, /* static initializer (debugobjects) */
38 WORK_STRUCT_COLOR_SHIFT = 5, /* color for workqueue flushing */
39 #else
40 WORK_STRUCT_COLOR_SHIFT = 4, /* color for workqueue flushing */
41 #endif
42
43 WORK_STRUCT_COLOR_BITS = 4,
44
45 WORK_STRUCT_PENDING = 1 << WORK_STRUCT_PENDING_BIT,
46 WORK_STRUCT_INACTIVE = 1 << WORK_STRUCT_INACTIVE_BIT,
47 WORK_STRUCT_PWQ = 1 << WORK_STRUCT_PWQ_BIT,
48 WORK_STRUCT_LINKED = 1 << WORK_STRUCT_LINKED_BIT,
49 #ifdef CONFIG_DEBUG_OBJECTS_WORK
50 WORK_STRUCT_STATIC = 1 << WORK_STRUCT_STATIC_BIT,
51 #else
52 WORK_STRUCT_STATIC = 0,
53 #endif
54
55 WORK_NR_COLORS = (1 << WORK_STRUCT_COLOR_BITS),
56
57 /* not bound to any CPU, prefer the local CPU */
58 WORK_CPU_UNBOUND = NR_CPUS,
59
60 /*
61 * Reserve 8 bits off of pwq pointer w/ debugobjects turned off.
62 * This makes pwqs aligned to 256 bytes and allows 16 workqueue
63 * flush colors.
64 */
65 WORK_STRUCT_FLAG_BITS = WORK_STRUCT_COLOR_SHIFT +
66 WORK_STRUCT_COLOR_BITS,
67
68 /* data contains off-queue information when !WORK_STRUCT_PWQ */
69 WORK_OFFQ_FLAG_BASE = WORK_STRUCT_COLOR_SHIFT,
70
71 __WORK_OFFQ_CANCELING = WORK_OFFQ_FLAG_BASE,
72
73 /*
74 * When a work item is off queue, its high bits point to the last
75 * pool it was on. Cap at 31 bits and use the highest number to
76 * indicate that no pool is associated.
77 */
78 WORK_OFFQ_FLAG_BITS = 1,
79 WORK_OFFQ_POOL_SHIFT = WORK_OFFQ_FLAG_BASE + WORK_OFFQ_FLAG_BITS,
80 WORK_OFFQ_LEFT = BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT,
81 WORK_OFFQ_POOL_BITS = WORK_OFFQ_LEFT <= 31 ? WORK_OFFQ_LEFT : 31,
82
83 /* bit mask for work_busy() return values */
84 WORK_BUSY_PENDING = 1 << 0,
85 WORK_BUSY_RUNNING = 1 << 1,
86
87 /* maximum string length for set_worker_desc() */
88 WORKER_DESC_LEN = 24,
89 };
90
91 /* Convenience constants - of type 'unsigned long', not 'enum'! */
92 #define WORK_OFFQ_CANCELING (1ul << __WORK_OFFQ_CANCELING)
93 #define WORK_OFFQ_POOL_NONE ((1ul << WORK_OFFQ_POOL_BITS) - 1)
94 #define WORK_STRUCT_NO_POOL (WORK_OFFQ_POOL_NONE << WORK_OFFQ_POOL_SHIFT)
95
96 #define WORK_STRUCT_FLAG_MASK ((1ul << WORK_STRUCT_FLAG_BITS) - 1)
97 #define WORK_STRUCT_WQ_DATA_MASK (~WORK_STRUCT_FLAG_MASK)
98
99 struct work_struct {
100 atomic_long_t data;
101 struct list_head entry;
102 work_func_t func;
103 #ifdef CONFIG_LOCKDEP
104 struct lockdep_map lockdep_map;
105 #endif
106 ANDROID_KABI_RESERVE(1);
107 ANDROID_KABI_RESERVE(2);
108 };
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 /**
135 * struct workqueue_attrs - A struct for workqueue attributes.
136 *
137 * This can be used to change attributes of an unbound workqueue.
138 */
139 struct workqueue_attrs {
140 /**
141 * @nice: nice level
142 */
143 int nice;
144
145 /**
146 * @cpumask: allowed CPUs
147 */
148 cpumask_var_t cpumask;
149
150 /**
151 * @no_numa: disable NUMA affinity
152 *
153 * Unlike other fields, ``no_numa`` isn't a property of a worker_pool. It
154 * only modifies how :c:func:`apply_workqueue_attrs` select pools and thus
155 * doesn't participate in pool hash calculations or equality comparisons.
156 */
157 bool no_numa;
158 };
159
to_delayed_work(struct work_struct * work)160 static inline struct delayed_work *to_delayed_work(struct work_struct *work)
161 {
162 return container_of(work, struct delayed_work, work);
163 }
164
to_rcu_work(struct work_struct * work)165 static inline struct rcu_work *to_rcu_work(struct work_struct *work)
166 {
167 return container_of(work, struct rcu_work, work);
168 }
169
170 struct execute_work {
171 struct work_struct work;
172 };
173
174 #ifdef CONFIG_LOCKDEP
175 /*
176 * NB: because we have to copy the lockdep_map, setting _key
177 * here is required, otherwise it could get initialised to the
178 * copy of the lockdep_map!
179 */
180 #define __WORK_INIT_LOCKDEP_MAP(n, k) \
181 .lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k),
182 #else
183 #define __WORK_INIT_LOCKDEP_MAP(n, k)
184 #endif
185
186 #define __WORK_INITIALIZER(n, f) { \
187 .data = WORK_DATA_STATIC_INIT(), \
188 .entry = { &(n).entry, &(n).entry }, \
189 .func = (f), \
190 __WORK_INIT_LOCKDEP_MAP(#n, &(n)) \
191 }
192
193 #define __DELAYED_WORK_INITIALIZER(n, f, tflags) { \
194 .work = __WORK_INITIALIZER((n).work, (f)), \
195 .timer = __TIMER_INITIALIZER(delayed_work_timer_fn,\
196 (tflags) | TIMER_IRQSAFE), \
197 }
198
199 #define DECLARE_WORK(n, f) \
200 struct work_struct n = __WORK_INITIALIZER(n, f)
201
202 #define DECLARE_DELAYED_WORK(n, f) \
203 struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, 0)
204
205 #define DECLARE_DEFERRABLE_WORK(n, f) \
206 struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, TIMER_DEFERRABLE)
207
208 #ifdef CONFIG_DEBUG_OBJECTS_WORK
209 extern void __init_work(struct work_struct *work, int onstack);
210 extern void destroy_work_on_stack(struct work_struct *work);
211 extern void destroy_delayed_work_on_stack(struct delayed_work *work);
work_static(struct work_struct * work)212 static inline unsigned int work_static(struct work_struct *work)
213 {
214 return *work_data_bits(work) & WORK_STRUCT_STATIC;
215 }
216 #else
__init_work(struct work_struct * work,int onstack)217 static inline void __init_work(struct work_struct *work, int onstack) { }
destroy_work_on_stack(struct work_struct * work)218 static inline void destroy_work_on_stack(struct work_struct *work) { }
destroy_delayed_work_on_stack(struct delayed_work * work)219 static inline void destroy_delayed_work_on_stack(struct delayed_work *work) { }
work_static(struct work_struct * work)220 static inline unsigned int work_static(struct work_struct *work) { return 0; }
221 #endif
222
223 /*
224 * initialize all of a work item in one go
225 *
226 * NOTE! No point in using "atomic_long_set()": using a direct
227 * assignment of the work data initializer allows the compiler
228 * to generate better code.
229 */
230 #ifdef CONFIG_LOCKDEP
231 #define __INIT_WORK(_work, _func, _onstack) \
232 do { \
233 static struct lock_class_key __key; \
234 \
235 __init_work((_work), _onstack); \
236 (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
237 lockdep_init_map(&(_work)->lockdep_map, "(work_completion)"#_work, &__key, 0); \
238 INIT_LIST_HEAD(&(_work)->entry); \
239 (_work)->func = (_func); \
240 } while (0)
241 #else
242 #define __INIT_WORK(_work, _func, _onstack) \
243 do { \
244 __init_work((_work), _onstack); \
245 (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
246 INIT_LIST_HEAD(&(_work)->entry); \
247 (_work)->func = (_func); \
248 } while (0)
249 #endif
250
251 #define INIT_WORK(_work, _func) \
252 __INIT_WORK((_work), (_func), 0)
253
254 #define INIT_WORK_ONSTACK(_work, _func) \
255 __INIT_WORK((_work), (_func), 1)
256
257 #define __INIT_DELAYED_WORK(_work, _func, _tflags) \
258 do { \
259 INIT_WORK(&(_work)->work, (_func)); \
260 __init_timer(&(_work)->timer, \
261 delayed_work_timer_fn, \
262 (_tflags) | TIMER_IRQSAFE); \
263 } while (0)
264
265 #define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags) \
266 do { \
267 INIT_WORK_ONSTACK(&(_work)->work, (_func)); \
268 __init_timer_on_stack(&(_work)->timer, \
269 delayed_work_timer_fn, \
270 (_tflags) | TIMER_IRQSAFE); \
271 } while (0)
272
273 #define INIT_DELAYED_WORK(_work, _func) \
274 __INIT_DELAYED_WORK(_work, _func, 0)
275
276 #define INIT_DELAYED_WORK_ONSTACK(_work, _func) \
277 __INIT_DELAYED_WORK_ONSTACK(_work, _func, 0)
278
279 #define INIT_DEFERRABLE_WORK(_work, _func) \
280 __INIT_DELAYED_WORK(_work, _func, TIMER_DEFERRABLE)
281
282 #define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func) \
283 __INIT_DELAYED_WORK_ONSTACK(_work, _func, TIMER_DEFERRABLE)
284
285 #define INIT_RCU_WORK(_work, _func) \
286 INIT_WORK(&(_work)->work, (_func))
287
288 #define INIT_RCU_WORK_ONSTACK(_work, _func) \
289 INIT_WORK_ONSTACK(&(_work)->work, (_func))
290
291 /**
292 * work_pending - Find out whether a work item is currently pending
293 * @work: The work item in question
294 */
295 #define work_pending(work) \
296 test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
297
298 /**
299 * delayed_work_pending - Find out whether a delayable work item is currently
300 * pending
301 * @w: The work item in question
302 */
303 #define delayed_work_pending(w) \
304 work_pending(&(w)->work)
305
306 /*
307 * Workqueue flags and constants. For details, please refer to
308 * Documentation/core-api/workqueue.rst.
309 */
310 enum {
311 WQ_UNBOUND = 1 << 1, /* not bound to any cpu */
312 WQ_FREEZABLE = 1 << 2, /* freeze during suspend */
313 WQ_MEM_RECLAIM = 1 << 3, /* may be used for memory reclaim */
314 WQ_HIGHPRI = 1 << 4, /* high priority */
315 WQ_CPU_INTENSIVE = 1 << 5, /* cpu intensive workqueue */
316 WQ_SYSFS = 1 << 6, /* visible in sysfs, see workqueue_sysfs_register() */
317
318 /*
319 * Per-cpu workqueues are generally preferred because they tend to
320 * show better performance thanks to cache locality. Per-cpu
321 * workqueues exclude the scheduler from choosing the CPU to
322 * execute the worker threads, which has an unfortunate side effect
323 * of increasing power consumption.
324 *
325 * The scheduler considers a CPU idle if it doesn't have any task
326 * to execute and tries to keep idle cores idle to conserve power;
327 * however, for example, a per-cpu work item scheduled from an
328 * interrupt handler on an idle CPU will force the scheduler to
329 * execute the work item on that CPU breaking the idleness, which in
330 * turn may lead to more scheduling choices which are sub-optimal
331 * in terms of power consumption.
332 *
333 * Workqueues marked with WQ_POWER_EFFICIENT are per-cpu by default
334 * but become unbound if workqueue.power_efficient kernel param is
335 * specified. Per-cpu workqueues which are identified to
336 * contribute significantly to power-consumption are identified and
337 * marked with this flag and enabling the power_efficient mode
338 * leads to noticeable power saving at the cost of small
339 * performance disadvantage.
340 *
341 * http://thread.gmane.org/gmane.linux.kernel/1480396
342 */
343 WQ_POWER_EFFICIENT = 1 << 7,
344
345 __WQ_DRAINING = 1 << 16, /* internal: workqueue is draining */
346 __WQ_ORDERED = 1 << 17, /* internal: workqueue is ordered */
347 __WQ_LEGACY = 1 << 18, /* internal: create*_workqueue() */
348 __WQ_ORDERED_EXPLICIT = 1 << 19, /* internal: alloc_ordered_workqueue() */
349
350 WQ_MAX_ACTIVE = 512, /* I like 512, better ideas? */
351 WQ_MAX_UNBOUND_PER_CPU = 4, /* 4 * #cpus for unbound wq */
352 WQ_DFL_ACTIVE = WQ_MAX_ACTIVE / 2,
353 };
354
355 /* unbound wq's aren't per-cpu, scale max_active according to #cpus */
356 #define WQ_UNBOUND_MAX_ACTIVE \
357 max_t(int, WQ_MAX_ACTIVE, num_possible_cpus() * WQ_MAX_UNBOUND_PER_CPU)
358
359 /*
360 * System-wide workqueues which are always present.
361 *
362 * system_wq is the one used by schedule[_delayed]_work[_on]().
363 * Multi-CPU multi-threaded. There are users which expect relatively
364 * short queue flush time. Don't queue works which can run for too
365 * long.
366 *
367 * system_highpri_wq is similar to system_wq but for work items which
368 * require WQ_HIGHPRI.
369 *
370 * system_long_wq is similar to system_wq but may host long running
371 * works. Queue flushing might take relatively long.
372 *
373 * system_unbound_wq is unbound workqueue. Workers are not bound to
374 * any specific CPU, not concurrency managed, and all queued works are
375 * executed immediately as long as max_active limit is not reached and
376 * resources are available.
377 *
378 * system_freezable_wq is equivalent to system_wq except that it's
379 * freezable.
380 *
381 * *_power_efficient_wq are inclined towards saving power and converted
382 * into WQ_UNBOUND variants if 'wq_power_efficient' is enabled; otherwise,
383 * they are same as their non-power-efficient counterparts - e.g.
384 * system_power_efficient_wq is identical to system_wq if
385 * 'wq_power_efficient' is disabled. See WQ_POWER_EFFICIENT for more info.
386 */
387 extern struct workqueue_struct *system_wq;
388 extern struct workqueue_struct *system_highpri_wq;
389 extern struct workqueue_struct *system_long_wq;
390 extern struct workqueue_struct *system_unbound_wq;
391 extern struct workqueue_struct *system_freezable_wq;
392 extern struct workqueue_struct *system_power_efficient_wq;
393 extern struct workqueue_struct *system_freezable_power_efficient_wq;
394
395 /**
396 * alloc_workqueue - allocate a workqueue
397 * @fmt: printf format for the name of the workqueue
398 * @flags: WQ_* flags
399 * @max_active: max in-flight work items, 0 for default
400 * remaining args: args for @fmt
401 *
402 * Allocate a workqueue with the specified parameters. For detailed
403 * information on WQ_* flags, please refer to
404 * Documentation/core-api/workqueue.rst.
405 *
406 * RETURNS:
407 * Pointer to the allocated workqueue on success, %NULL on failure.
408 */
409 __printf(1, 4) struct workqueue_struct *
410 alloc_workqueue(const char *fmt, unsigned int flags, int max_active, ...);
411
412 /**
413 * alloc_ordered_workqueue - allocate an ordered workqueue
414 * @fmt: printf format for the name of the workqueue
415 * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
416 * @args...: args for @fmt
417 *
418 * Allocate an ordered workqueue. An ordered workqueue executes at
419 * most one work item at any given time in the queued order. They are
420 * implemented as unbound workqueues with @max_active of one.
421 *
422 * RETURNS:
423 * Pointer to the allocated workqueue on success, %NULL on failure.
424 */
425 #define alloc_ordered_workqueue(fmt, flags, args...) \
426 alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | \
427 __WQ_ORDERED_EXPLICIT | (flags), 1, ##args)
428
429 #define create_workqueue(name) \
430 alloc_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, 1, (name))
431 #define create_freezable_workqueue(name) \
432 alloc_workqueue("%s", __WQ_LEGACY | WQ_FREEZABLE | WQ_UNBOUND | \
433 WQ_MEM_RECLAIM, 1, (name))
434 #define create_singlethread_workqueue(name) \
435 alloc_ordered_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, name)
436
437 extern void destroy_workqueue(struct workqueue_struct *wq);
438
439 struct workqueue_attrs *alloc_workqueue_attrs(void);
440 void free_workqueue_attrs(struct workqueue_attrs *attrs);
441 int apply_workqueue_attrs(struct workqueue_struct *wq,
442 const struct workqueue_attrs *attrs);
443 int workqueue_set_unbound_cpumask(cpumask_var_t cpumask);
444
445 extern bool queue_work_on(int cpu, struct workqueue_struct *wq,
446 struct work_struct *work);
447 extern bool queue_work_node(int node, struct workqueue_struct *wq,
448 struct work_struct *work);
449 extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
450 struct delayed_work *work, unsigned long delay);
451 extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
452 struct delayed_work *dwork, unsigned long delay);
453 extern bool queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork);
454
455 extern void flush_workqueue(struct workqueue_struct *wq);
456 extern void drain_workqueue(struct workqueue_struct *wq);
457
458 extern int schedule_on_each_cpu(work_func_t func);
459
460 int execute_in_process_context(work_func_t fn, struct execute_work *);
461
462 extern bool flush_work(struct work_struct *work);
463 extern bool cancel_work(struct work_struct *work);
464 extern bool cancel_work_sync(struct work_struct *work);
465
466 extern bool flush_delayed_work(struct delayed_work *dwork);
467 extern bool cancel_delayed_work(struct delayed_work *dwork);
468 extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
469
470 extern bool flush_rcu_work(struct rcu_work *rwork);
471
472 extern void workqueue_set_max_active(struct workqueue_struct *wq,
473 int max_active);
474 extern struct work_struct *current_work(void);
475 extern bool current_is_workqueue_rescuer(void);
476 extern bool workqueue_congested(int cpu, struct workqueue_struct *wq);
477 extern unsigned int work_busy(struct work_struct *work);
478 extern __printf(1, 2) void set_worker_desc(const char *fmt, ...);
479 extern void print_worker_info(const char *log_lvl, struct task_struct *task);
480 extern void show_all_workqueues(void);
481 extern void show_one_workqueue(struct workqueue_struct *wq);
482 extern void wq_worker_comm(char *buf, size_t size, struct task_struct *task);
483
484 /**
485 * queue_work - queue work on a workqueue
486 * @wq: workqueue to use
487 * @work: work to queue
488 *
489 * Returns %false if @work was already on a queue, %true otherwise.
490 *
491 * We queue the work to the CPU on which it was submitted, but if the CPU dies
492 * it can be processed by another CPU.
493 *
494 * Memory-ordering properties: If it returns %true, guarantees that all stores
495 * preceding the call to queue_work() in the program order will be visible from
496 * the CPU which will execute @work by the time such work executes, e.g.,
497 *
498 * { x is initially 0 }
499 *
500 * CPU0 CPU1
501 *
502 * WRITE_ONCE(x, 1); [ @work is being executed ]
503 * r0 = queue_work(wq, work); r1 = READ_ONCE(x);
504 *
505 * Forbids: r0 == true && r1 == 0
506 */
queue_work(struct workqueue_struct * wq,struct work_struct * work)507 static inline bool queue_work(struct workqueue_struct *wq,
508 struct work_struct *work)
509 {
510 return queue_work_on(WORK_CPU_UNBOUND, wq, work);
511 }
512
513 /**
514 * queue_delayed_work - queue work on a workqueue after delay
515 * @wq: workqueue to use
516 * @dwork: delayable work to queue
517 * @delay: number of jiffies to wait before queueing
518 *
519 * Equivalent to queue_delayed_work_on() but tries to use the local CPU.
520 */
queue_delayed_work(struct workqueue_struct * wq,struct delayed_work * dwork,unsigned long delay)521 static inline bool queue_delayed_work(struct workqueue_struct *wq,
522 struct delayed_work *dwork,
523 unsigned long delay)
524 {
525 return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
526 }
527
528 /**
529 * mod_delayed_work - modify delay of or queue a delayed work
530 * @wq: workqueue to use
531 * @dwork: work to queue
532 * @delay: number of jiffies to wait before queueing
533 *
534 * mod_delayed_work_on() on local CPU.
535 */
mod_delayed_work(struct workqueue_struct * wq,struct delayed_work * dwork,unsigned long delay)536 static inline bool mod_delayed_work(struct workqueue_struct *wq,
537 struct delayed_work *dwork,
538 unsigned long delay)
539 {
540 return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
541 }
542
543 /**
544 * schedule_work_on - put work task on a specific cpu
545 * @cpu: cpu to put the work task on
546 * @work: job to be done
547 *
548 * This puts a job on a specific cpu
549 */
schedule_work_on(int cpu,struct work_struct * work)550 static inline bool schedule_work_on(int cpu, struct work_struct *work)
551 {
552 return queue_work_on(cpu, system_wq, work);
553 }
554
555 /**
556 * schedule_work - put work task in global workqueue
557 * @work: job to be done
558 *
559 * Returns %false if @work was already on the kernel-global workqueue and
560 * %true otherwise.
561 *
562 * This puts a job in the kernel-global workqueue if it was not already
563 * queued and leaves it in the same position on the kernel-global
564 * workqueue otherwise.
565 *
566 * Shares the same memory-ordering properties of queue_work(), cf. the
567 * DocBook header of queue_work().
568 */
schedule_work(struct work_struct * work)569 static inline bool schedule_work(struct work_struct *work)
570 {
571 return queue_work(system_wq, work);
572 }
573
574 /**
575 * flush_scheduled_work - ensure that any scheduled work has run to completion.
576 *
577 * Forces execution of the kernel-global workqueue and blocks until its
578 * completion.
579 *
580 * Think twice before calling this function! It's very easy to get into
581 * trouble if you don't take great care. Either of the following situations
582 * will lead to deadlock:
583 *
584 * One of the work items currently on the workqueue needs to acquire
585 * a lock held by your code or its caller.
586 *
587 * Your code is running in the context of a work routine.
588 *
589 * They will be detected by lockdep when they occur, but the first might not
590 * occur very often. It depends on what work items are on the workqueue and
591 * what locks they need, which you have no control over.
592 *
593 * In most situations flushing the entire workqueue is overkill; you merely
594 * need to know that a particular work item isn't queued and isn't running.
595 * In such cases you should use cancel_delayed_work_sync() or
596 * cancel_work_sync() instead.
597 */
flush_scheduled_work(void)598 static inline void flush_scheduled_work(void)
599 {
600 flush_workqueue(system_wq);
601 }
602
603 /**
604 * schedule_delayed_work_on - queue work in global workqueue on CPU after delay
605 * @cpu: cpu to use
606 * @dwork: job to be done
607 * @delay: number of jiffies to wait
608 *
609 * After waiting for a given time this puts a job in the kernel-global
610 * workqueue on the specified CPU.
611 */
schedule_delayed_work_on(int cpu,struct delayed_work * dwork,unsigned long delay)612 static inline bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork,
613 unsigned long delay)
614 {
615 return queue_delayed_work_on(cpu, system_wq, dwork, delay);
616 }
617
618 /**
619 * schedule_delayed_work - put work task in global workqueue after delay
620 * @dwork: job to be done
621 * @delay: number of jiffies to wait or 0 for immediate execution
622 *
623 * After waiting for a given time this puts a job in the kernel-global
624 * workqueue.
625 */
schedule_delayed_work(struct delayed_work * dwork,unsigned long delay)626 static inline bool schedule_delayed_work(struct delayed_work *dwork,
627 unsigned long delay)
628 {
629 return queue_delayed_work(system_wq, dwork, delay);
630 }
631
632 #ifndef CONFIG_SMP
work_on_cpu(int cpu,long (* fn)(void *),void * arg)633 static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
634 {
635 return fn(arg);
636 }
work_on_cpu_safe(int cpu,long (* fn)(void *),void * arg)637 static inline long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg)
638 {
639 return fn(arg);
640 }
641 #else
642 long work_on_cpu(int cpu, long (*fn)(void *), void *arg);
643 long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg);
644 #endif /* CONFIG_SMP */
645
646 #ifdef CONFIG_FREEZER
647 extern void freeze_workqueues_begin(void);
648 extern bool freeze_workqueues_busy(void);
649 extern void thaw_workqueues(void);
650 #endif /* CONFIG_FREEZER */
651
652 #ifdef CONFIG_SYSFS
653 int workqueue_sysfs_register(struct workqueue_struct *wq);
654 #else /* CONFIG_SYSFS */
workqueue_sysfs_register(struct workqueue_struct * wq)655 static inline int workqueue_sysfs_register(struct workqueue_struct *wq)
656 { return 0; }
657 #endif /* CONFIG_SYSFS */
658
659 #ifdef CONFIG_WQ_WATCHDOG
660 void wq_watchdog_touch(int cpu);
661 #else /* CONFIG_WQ_WATCHDOG */
wq_watchdog_touch(int cpu)662 static inline void wq_watchdog_touch(int cpu) { }
663 #endif /* CONFIG_WQ_WATCHDOG */
664
665 #ifdef CONFIG_SMP
666 int workqueue_prepare_cpu(unsigned int cpu);
667 int workqueue_online_cpu(unsigned int cpu);
668 int workqueue_offline_cpu(unsigned int cpu);
669 #endif
670
671 void __init workqueue_init_early(void);
672 void __init workqueue_init(void);
673
674 #endif
675