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_DELAYED_BIT = 1, /* work item is delayed */
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_DELAYED = 1 << WORK_STRUCT_DELAYED_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 /*
56 * The last color is no color used for works which don't
57 * participate in workqueue flushing.
58 */
59 WORK_NR_COLORS = (1 << WORK_STRUCT_COLOR_BITS) - 1,
60 WORK_NO_COLOR = WORK_NR_COLORS,
61
62 /* not bound to any CPU, prefer the local CPU */
63 WORK_CPU_UNBOUND = NR_CPUS,
64
65 /*
66 * Reserve 8 bits off of pwq pointer w/ debugobjects turned off.
67 * This makes pwqs aligned to 256 bytes and allows 15 workqueue
68 * flush colors.
69 */
70 WORK_STRUCT_FLAG_BITS = WORK_STRUCT_COLOR_SHIFT +
71 WORK_STRUCT_COLOR_BITS,
72
73 /* data contains off-queue information when !WORK_STRUCT_PWQ */
74 WORK_OFFQ_FLAG_BASE = WORK_STRUCT_COLOR_SHIFT,
75
76 __WORK_OFFQ_CANCELING = WORK_OFFQ_FLAG_BASE,
77 WORK_OFFQ_CANCELING = (1 << __WORK_OFFQ_CANCELING),
78
79 /*
80 * When a work item is off queue, its high bits point to the last
81 * pool it was on. Cap at 31 bits and use the highest number to
82 * indicate that no pool is associated.
83 */
84 WORK_OFFQ_FLAG_BITS = 1,
85 WORK_OFFQ_POOL_SHIFT = WORK_OFFQ_FLAG_BASE + WORK_OFFQ_FLAG_BITS,
86 WORK_OFFQ_LEFT = BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT,
87 WORK_OFFQ_POOL_BITS = WORK_OFFQ_LEFT <= 31 ? WORK_OFFQ_LEFT : 31,
88 WORK_OFFQ_POOL_NONE = (1LU << WORK_OFFQ_POOL_BITS) - 1,
89
90 /* convenience constants */
91 WORK_STRUCT_FLAG_MASK = (1UL << WORK_STRUCT_FLAG_BITS) - 1,
92 WORK_STRUCT_WQ_DATA_MASK = ~WORK_STRUCT_FLAG_MASK,
93 WORK_STRUCT_NO_POOL = (unsigned long)WORK_OFFQ_POOL_NONE << WORK_OFFQ_POOL_SHIFT,
94
95 /* bit mask for work_busy() return values */
96 WORK_BUSY_PENDING = 1 << 0,
97 WORK_BUSY_RUNNING = 1 << 1,
98
99 /* maximum string length for set_worker_desc() */
100 WORKER_DESC_LEN = 24,
101 };
102
103 struct work_struct {
104 atomic_long_t data;
105 struct list_head entry;
106 work_func_t func;
107 #ifdef CONFIG_LOCKDEP
108 struct lockdep_map lockdep_map;
109 #endif
110 ANDROID_KABI_RESERVE(1);
111 ANDROID_KABI_RESERVE(2);
112 };
113
114 #define WORK_DATA_INIT() ATOMIC_LONG_INIT((unsigned long)WORK_STRUCT_NO_POOL)
115 #define WORK_DATA_STATIC_INIT() \
116 ATOMIC_LONG_INIT((unsigned long)(WORK_STRUCT_NO_POOL | WORK_STRUCT_STATIC))
117
118 struct delayed_work {
119 struct work_struct work;
120 struct timer_list timer;
121
122 /* target workqueue and CPU ->timer uses to queue ->work */
123 struct workqueue_struct *wq;
124 int cpu;
125
126 ANDROID_KABI_RESERVE(1);
127 ANDROID_KABI_RESERVE(2);
128 };
129
130 struct rcu_work {
131 struct work_struct work;
132 struct rcu_head rcu;
133
134 /* target workqueue ->rcu uses to queue ->work */
135 struct workqueue_struct *wq;
136 };
137
138 /**
139 * struct workqueue_attrs - A struct for workqueue attributes.
140 *
141 * This can be used to change attributes of an unbound workqueue.
142 */
143 struct workqueue_attrs {
144 /**
145 * @nice: nice level
146 */
147 int nice;
148
149 /**
150 * @cpumask: allowed CPUs
151 */
152 cpumask_var_t cpumask;
153
154 /**
155 * @no_numa: disable NUMA affinity
156 *
157 * Unlike other fields, ``no_numa`` isn't a property of a worker_pool. It
158 * only modifies how :c:func:`apply_workqueue_attrs` select pools and thus
159 * doesn't participate in pool hash calculations or equality comparisons.
160 */
161 bool no_numa;
162 };
163
to_delayed_work(struct work_struct * work)164 static inline struct delayed_work *to_delayed_work(struct work_struct *work)
165 {
166 return container_of(work, struct delayed_work, work);
167 }
168
to_rcu_work(struct work_struct * work)169 static inline struct rcu_work *to_rcu_work(struct work_struct *work)
170 {
171 return container_of(work, struct rcu_work, work);
172 }
173
174 struct execute_work {
175 struct work_struct work;
176 };
177
178 #ifdef CONFIG_LOCKDEP
179 /*
180 * NB: because we have to copy the lockdep_map, setting _key
181 * here is required, otherwise it could get initialised to the
182 * copy of the lockdep_map!
183 */
184 #define __WORK_INIT_LOCKDEP_MAP(n, k) \
185 .lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k),
186 #else
187 #define __WORK_INIT_LOCKDEP_MAP(n, k)
188 #endif
189
190 #define __WORK_INITIALIZER(n, f) { \
191 .data = WORK_DATA_STATIC_INIT(), \
192 .entry = { &(n).entry, &(n).entry }, \
193 .func = (f), \
194 __WORK_INIT_LOCKDEP_MAP(#n, &(n)) \
195 }
196
197 #define __DELAYED_WORK_INITIALIZER(n, f, tflags) { \
198 .work = __WORK_INITIALIZER((n).work, (f)), \
199 .timer = __TIMER_INITIALIZER(delayed_work_timer_fn,\
200 (tflags) | TIMER_IRQSAFE), \
201 }
202
203 #define DECLARE_WORK(n, f) \
204 struct work_struct n = __WORK_INITIALIZER(n, f)
205
206 #define DECLARE_DELAYED_WORK(n, f) \
207 struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, 0)
208
209 #define DECLARE_DEFERRABLE_WORK(n, f) \
210 struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, TIMER_DEFERRABLE)
211
212 #ifdef CONFIG_DEBUG_OBJECTS_WORK
213 extern void __init_work(struct work_struct *work, int onstack);
214 extern void destroy_work_on_stack(struct work_struct *work);
215 extern void destroy_delayed_work_on_stack(struct delayed_work *work);
work_static(struct work_struct * work)216 static inline unsigned int work_static(struct work_struct *work)
217 {
218 return *work_data_bits(work) & WORK_STRUCT_STATIC;
219 }
220 #else
__init_work(struct work_struct * work,int onstack)221 static inline void __init_work(struct work_struct *work, int onstack) { }
destroy_work_on_stack(struct work_struct * work)222 static inline void destroy_work_on_stack(struct work_struct *work) { }
destroy_delayed_work_on_stack(struct delayed_work * work)223 static inline void destroy_delayed_work_on_stack(struct delayed_work *work) { }
work_static(struct work_struct * work)224 static inline unsigned int work_static(struct work_struct *work) { return 0; }
225 #endif
226
227 /*
228 * initialize all of a work item in one go
229 *
230 * NOTE! No point in using "atomic_long_set()": using a direct
231 * assignment of the work data initializer allows the compiler
232 * to generate better code.
233 */
234 #ifdef CONFIG_LOCKDEP
235 #define __INIT_WORK(_work, _func, _onstack) \
236 do { \
237 static struct lock_class_key __key; \
238 \
239 __init_work((_work), _onstack); \
240 (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
241 lockdep_init_map(&(_work)->lockdep_map, "(work_completion)"#_work, &__key, 0); \
242 INIT_LIST_HEAD(&(_work)->entry); \
243 (_work)->func = (_func); \
244 } while (0)
245 #else
246 #define __INIT_WORK(_work, _func, _onstack) \
247 do { \
248 __init_work((_work), _onstack); \
249 (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
250 INIT_LIST_HEAD(&(_work)->entry); \
251 (_work)->func = (_func); \
252 } while (0)
253 #endif
254
255 #define INIT_WORK(_work, _func) \
256 __INIT_WORK((_work), (_func), 0)
257
258 #define INIT_WORK_ONSTACK(_work, _func) \
259 __INIT_WORK((_work), (_func), 1)
260
261 #define __INIT_DELAYED_WORK(_work, _func, _tflags) \
262 do { \
263 INIT_WORK(&(_work)->work, (_func)); \
264 __init_timer(&(_work)->timer, \
265 delayed_work_timer_fn, \
266 (_tflags) | TIMER_IRQSAFE); \
267 } while (0)
268
269 #define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags) \
270 do { \
271 INIT_WORK_ONSTACK(&(_work)->work, (_func)); \
272 __init_timer_on_stack(&(_work)->timer, \
273 delayed_work_timer_fn, \
274 (_tflags) | TIMER_IRQSAFE); \
275 } while (0)
276
277 #define INIT_DELAYED_WORK(_work, _func) \
278 __INIT_DELAYED_WORK(_work, _func, 0)
279
280 #define INIT_DELAYED_WORK_ONSTACK(_work, _func) \
281 __INIT_DELAYED_WORK_ONSTACK(_work, _func, 0)
282
283 #define INIT_DEFERRABLE_WORK(_work, _func) \
284 __INIT_DELAYED_WORK(_work, _func, TIMER_DEFERRABLE)
285
286 #define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func) \
287 __INIT_DELAYED_WORK_ONSTACK(_work, _func, TIMER_DEFERRABLE)
288
289 #define INIT_RCU_WORK(_work, _func) \
290 INIT_WORK(&(_work)->work, (_func))
291
292 #define INIT_RCU_WORK_ONSTACK(_work, _func) \
293 INIT_WORK_ONSTACK(&(_work)->work, (_func))
294
295 /**
296 * work_pending - Find out whether a work item is currently pending
297 * @work: The work item in question
298 */
299 #define work_pending(work) \
300 test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
301
302 /**
303 * delayed_work_pending - Find out whether a delayable work item is currently
304 * pending
305 * @w: The work item in question
306 */
307 #define delayed_work_pending(w) \
308 work_pending(&(w)->work)
309
310 /*
311 * Workqueue flags and constants. For details, please refer to
312 * Documentation/core-api/workqueue.rst.
313 */
314 enum {
315 WQ_UNBOUND = 1 << 1, /* not bound to any cpu */
316 WQ_FREEZABLE = 1 << 2, /* freeze during suspend */
317 WQ_MEM_RECLAIM = 1 << 3, /* may be used for memory reclaim */
318 WQ_HIGHPRI = 1 << 4, /* high priority */
319 WQ_CPU_INTENSIVE = 1 << 5, /* cpu intensive workqueue */
320 WQ_SYSFS = 1 << 6, /* visible in sysfs, see wq_sysfs_register() */
321
322 /*
323 * Per-cpu workqueues are generally preferred because they tend to
324 * show better performance thanks to cache locality. Per-cpu
325 * workqueues exclude the scheduler from choosing the CPU to
326 * execute the worker threads, which has an unfortunate side effect
327 * of increasing power consumption.
328 *
329 * The scheduler considers a CPU idle if it doesn't have any task
330 * to execute and tries to keep idle cores idle to conserve power;
331 * however, for example, a per-cpu work item scheduled from an
332 * interrupt handler on an idle CPU will force the scheduler to
333 * excute the work item on that CPU breaking the idleness, which in
334 * turn may lead to more scheduling choices which are sub-optimal
335 * in terms of power consumption.
336 *
337 * Workqueues marked with WQ_POWER_EFFICIENT are per-cpu by default
338 * but become unbound if workqueue.power_efficient kernel param is
339 * specified. Per-cpu workqueues which are identified to
340 * contribute significantly to power-consumption are identified and
341 * marked with this flag and enabling the power_efficient mode
342 * leads to noticeable power saving at the cost of small
343 * performance disadvantage.
344 *
345 * http://thread.gmane.org/gmane.linux.kernel/1480396
346 */
347 WQ_POWER_EFFICIENT = 1 << 7,
348
349 __WQ_DRAINING = 1 << 16, /* internal: workqueue is draining */
350 __WQ_ORDERED = 1 << 17, /* internal: workqueue is ordered */
351 __WQ_LEGACY = 1 << 18, /* internal: create*_workqueue() */
352 __WQ_ORDERED_EXPLICIT = 1 << 19, /* internal: alloc_ordered_workqueue() */
353
354 WQ_MAX_ACTIVE = 512, /* I like 512, better ideas? */
355 WQ_MAX_UNBOUND_PER_CPU = 4, /* 4 * #cpus for unbound wq */
356 WQ_DFL_ACTIVE = WQ_MAX_ACTIVE / 2,
357 };
358
359 /* unbound wq's aren't per-cpu, scale max_active according to #cpus */
360 #define WQ_UNBOUND_MAX_ACTIVE \
361 max_t(int, WQ_MAX_ACTIVE, num_possible_cpus() * WQ_MAX_UNBOUND_PER_CPU)
362
363 /*
364 * System-wide workqueues which are always present.
365 *
366 * system_wq is the one used by schedule[_delayed]_work[_on]().
367 * Multi-CPU multi-threaded. There are users which expect relatively
368 * short queue flush time. Don't queue works which can run for too
369 * long.
370 *
371 * system_highpri_wq is similar to system_wq but for work items which
372 * require WQ_HIGHPRI.
373 *
374 * system_long_wq is similar to system_wq but may host long running
375 * works. Queue flushing might take relatively long.
376 *
377 * system_unbound_wq is unbound workqueue. Workers are not bound to
378 * any specific CPU, not concurrency managed, and all queued works are
379 * executed immediately as long as max_active limit is not reached and
380 * resources are available.
381 *
382 * system_freezable_wq is equivalent to system_wq except that it's
383 * freezable.
384 *
385 * *_power_efficient_wq are inclined towards saving power and converted
386 * into WQ_UNBOUND variants if 'wq_power_efficient' is enabled; otherwise,
387 * they are same as their non-power-efficient counterparts - e.g.
388 * system_power_efficient_wq is identical to system_wq if
389 * 'wq_power_efficient' is disabled. See WQ_POWER_EFFICIENT for more info.
390 */
391 extern struct workqueue_struct *system_wq;
392 extern struct workqueue_struct *system_highpri_wq;
393 extern struct workqueue_struct *system_long_wq;
394 extern struct workqueue_struct *system_unbound_wq;
395 extern struct workqueue_struct *system_freezable_wq;
396 extern struct workqueue_struct *system_power_efficient_wq;
397 extern struct workqueue_struct *system_freezable_power_efficient_wq;
398
399 /**
400 * alloc_workqueue - allocate a workqueue
401 * @fmt: printf format for the name of the workqueue
402 * @flags: WQ_* flags
403 * @max_active: max in-flight work items, 0 for default
404 * remaining args: args for @fmt
405 *
406 * Allocate a workqueue with the specified parameters. For detailed
407 * information on WQ_* flags, please refer to
408 * Documentation/core-api/workqueue.rst.
409 *
410 * RETURNS:
411 * Pointer to the allocated workqueue on success, %NULL on failure.
412 */
413 struct workqueue_struct *alloc_workqueue(const char *fmt,
414 unsigned int flags,
415 int max_active, ...);
416
417 /**
418 * alloc_ordered_workqueue - allocate an ordered workqueue
419 * @fmt: printf format for the name of the workqueue
420 * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
421 * @args...: args for @fmt
422 *
423 * Allocate an ordered workqueue. An ordered workqueue executes at
424 * most one work item at any given time in the queued order. They are
425 * implemented as unbound workqueues with @max_active of one.
426 *
427 * RETURNS:
428 * Pointer to the allocated workqueue on success, %NULL on failure.
429 */
430 #define alloc_ordered_workqueue(fmt, flags, args...) \
431 alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | \
432 __WQ_ORDERED_EXPLICIT | (flags), 1, ##args)
433
434 #define create_workqueue(name) \
435 alloc_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, 1, (name))
436 #define create_freezable_workqueue(name) \
437 alloc_workqueue("%s", __WQ_LEGACY | WQ_FREEZABLE | WQ_UNBOUND | \
438 WQ_MEM_RECLAIM, 1, (name))
439 #define create_singlethread_workqueue(name) \
440 alloc_ordered_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, name)
441
442 extern void destroy_workqueue(struct workqueue_struct *wq);
443
444 struct workqueue_attrs *alloc_workqueue_attrs(void);
445 void free_workqueue_attrs(struct workqueue_attrs *attrs);
446 int apply_workqueue_attrs(struct workqueue_struct *wq,
447 const struct workqueue_attrs *attrs);
448 int workqueue_set_unbound_cpumask(cpumask_var_t cpumask);
449
450 extern bool queue_work_on(int cpu, struct workqueue_struct *wq,
451 struct work_struct *work);
452 extern bool queue_work_node(int node, struct workqueue_struct *wq,
453 struct work_struct *work);
454 extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
455 struct delayed_work *work, unsigned long delay);
456 extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
457 struct delayed_work *dwork, unsigned long delay);
458 extern bool queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork);
459
460 extern void flush_workqueue(struct workqueue_struct *wq);
461 extern void drain_workqueue(struct workqueue_struct *wq);
462
463 extern int schedule_on_each_cpu(work_func_t func);
464
465 int execute_in_process_context(work_func_t fn, struct execute_work *);
466
467 extern bool flush_work(struct work_struct *work);
468 extern bool cancel_work_sync(struct work_struct *work);
469
470 extern bool flush_delayed_work(struct delayed_work *dwork);
471 extern bool cancel_delayed_work(struct delayed_work *dwork);
472 extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
473
474 extern bool flush_rcu_work(struct rcu_work *rwork);
475
476 extern void workqueue_set_max_active(struct workqueue_struct *wq,
477 int max_active);
478 extern struct work_struct *current_work(void);
479 extern bool current_is_workqueue_rescuer(void);
480 extern bool workqueue_congested(int cpu, struct workqueue_struct *wq);
481 extern unsigned int work_busy(struct work_struct *work);
482 extern __printf(1, 2) void set_worker_desc(const char *fmt, ...);
483 extern void print_worker_info(const char *log_lvl, struct task_struct *task);
484 extern void show_workqueue_state(void);
485 extern void wq_worker_comm(char *buf, size_t size, struct task_struct *task);
486
487 /**
488 * queue_work - queue work on a workqueue
489 * @wq: workqueue to use
490 * @work: work to queue
491 *
492 * Returns %false if @work was already on a queue, %true otherwise.
493 *
494 * We queue the work to the CPU on which it was submitted, but if the CPU dies
495 * it can be processed by another CPU.
496 *
497 * Memory-ordering properties: If it returns %true, guarantees that all stores
498 * preceding the call to queue_work() in the program order will be visible from
499 * the CPU which will execute @work by the time such work executes, e.g.,
500 *
501 * { x is initially 0 }
502 *
503 * CPU0 CPU1
504 *
505 * WRITE_ONCE(x, 1); [ @work is being executed ]
506 * r0 = queue_work(wq, work); r1 = READ_ONCE(x);
507 *
508 * Forbids: r0 == true && r1 == 0
509 */
queue_work(struct workqueue_struct * wq,struct work_struct * work)510 static inline bool queue_work(struct workqueue_struct *wq,
511 struct work_struct *work)
512 {
513 return queue_work_on(WORK_CPU_UNBOUND, wq, work);
514 }
515
516 /**
517 * queue_delayed_work - queue work on a workqueue after delay
518 * @wq: workqueue to use
519 * @dwork: delayable work to queue
520 * @delay: number of jiffies to wait before queueing
521 *
522 * Equivalent to queue_delayed_work_on() but tries to use the local CPU.
523 */
queue_delayed_work(struct workqueue_struct * wq,struct delayed_work * dwork,unsigned long delay)524 static inline bool queue_delayed_work(struct workqueue_struct *wq,
525 struct delayed_work *dwork,
526 unsigned long delay)
527 {
528 return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
529 }
530
531 /**
532 * mod_delayed_work - modify delay of or queue a delayed work
533 * @wq: workqueue to use
534 * @dwork: work to queue
535 * @delay: number of jiffies to wait before queueing
536 *
537 * mod_delayed_work_on() on local CPU.
538 */
mod_delayed_work(struct workqueue_struct * wq,struct delayed_work * dwork,unsigned long delay)539 static inline bool mod_delayed_work(struct workqueue_struct *wq,
540 struct delayed_work *dwork,
541 unsigned long delay)
542 {
543 return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
544 }
545
546 /**
547 * schedule_work_on - put work task on a specific cpu
548 * @cpu: cpu to put the work task on
549 * @work: job to be done
550 *
551 * This puts a job on a specific cpu
552 */
schedule_work_on(int cpu,struct work_struct * work)553 static inline bool schedule_work_on(int cpu, struct work_struct *work)
554 {
555 return queue_work_on(cpu, system_wq, work);
556 }
557
558 /**
559 * schedule_work - put work task in global workqueue
560 * @work: job to be done
561 *
562 * Returns %false if @work was already on the kernel-global workqueue and
563 * %true otherwise.
564 *
565 * This puts a job in the kernel-global workqueue if it was not already
566 * queued and leaves it in the same position on the kernel-global
567 * workqueue otherwise.
568 *
569 * Shares the same memory-ordering properties of queue_work(), cf. the
570 * DocBook header of queue_work().
571 */
schedule_work(struct work_struct * work)572 static inline bool schedule_work(struct work_struct *work)
573 {
574 return queue_work(system_wq, work);
575 }
576
577 /**
578 * flush_scheduled_work - ensure that any scheduled work has run to completion.
579 *
580 * Forces execution of the kernel-global workqueue and blocks until its
581 * completion.
582 *
583 * Think twice before calling this function! It's very easy to get into
584 * trouble if you don't take great care. Either of the following situations
585 * will lead to deadlock:
586 *
587 * One of the work items currently on the workqueue needs to acquire
588 * a lock held by your code or its caller.
589 *
590 * Your code is running in the context of a work routine.
591 *
592 * They will be detected by lockdep when they occur, but the first might not
593 * occur very often. It depends on what work items are on the workqueue and
594 * what locks they need, which you have no control over.
595 *
596 * In most situations flushing the entire workqueue is overkill; you merely
597 * need to know that a particular work item isn't queued and isn't running.
598 * In such cases you should use cancel_delayed_work_sync() or
599 * cancel_work_sync() instead.
600 */
flush_scheduled_work(void)601 static inline void flush_scheduled_work(void)
602 {
603 flush_workqueue(system_wq);
604 }
605
606 /**
607 * schedule_delayed_work_on - queue work in global workqueue on CPU after delay
608 * @cpu: cpu to use
609 * @dwork: job to be done
610 * @delay: number of jiffies to wait
611 *
612 * After waiting for a given time this puts a job in the kernel-global
613 * workqueue on the specified CPU.
614 */
schedule_delayed_work_on(int cpu,struct delayed_work * dwork,unsigned long delay)615 static inline bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork,
616 unsigned long delay)
617 {
618 return queue_delayed_work_on(cpu, system_wq, dwork, delay);
619 }
620
621 /**
622 * schedule_delayed_work - put work task in global workqueue after delay
623 * @dwork: job to be done
624 * @delay: number of jiffies to wait or 0 for immediate execution
625 *
626 * After waiting for a given time this puts a job in the kernel-global
627 * workqueue.
628 */
schedule_delayed_work(struct delayed_work * dwork,unsigned long delay)629 static inline bool schedule_delayed_work(struct delayed_work *dwork,
630 unsigned long delay)
631 {
632 return queue_delayed_work(system_wq, dwork, delay);
633 }
634
635 #ifndef CONFIG_SMP
work_on_cpu(int cpu,long (* fn)(void *),void * arg)636 static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
637 {
638 return fn(arg);
639 }
work_on_cpu_safe(int cpu,long (* fn)(void *),void * arg)640 static inline long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg)
641 {
642 return fn(arg);
643 }
644 #else
645 long work_on_cpu(int cpu, long (*fn)(void *), void *arg);
646 long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg);
647 #endif /* CONFIG_SMP */
648
649 #ifdef CONFIG_FREEZER
650 extern void freeze_workqueues_begin(void);
651 extern bool freeze_workqueues_busy(void);
652 extern void thaw_workqueues(void);
653 #endif /* CONFIG_FREEZER */
654
655 #ifdef CONFIG_SYSFS
656 int workqueue_sysfs_register(struct workqueue_struct *wq);
657 #else /* CONFIG_SYSFS */
workqueue_sysfs_register(struct workqueue_struct * wq)658 static inline int workqueue_sysfs_register(struct workqueue_struct *wq)
659 { return 0; }
660 #endif /* CONFIG_SYSFS */
661
662 #ifdef CONFIG_WQ_WATCHDOG
663 void wq_watchdog_touch(int cpu);
664 #else /* CONFIG_WQ_WATCHDOG */
wq_watchdog_touch(int cpu)665 static inline void wq_watchdog_touch(int cpu) { }
666 #endif /* CONFIG_WQ_WATCHDOG */
667
668 #ifdef CONFIG_SMP
669 int workqueue_prepare_cpu(unsigned int cpu);
670 int workqueue_online_cpu(unsigned int cpu);
671 int workqueue_offline_cpu(unsigned int cpu);
672 #endif
673
674 void __init workqueue_init_early(void);
675 void __init workqueue_init(void);
676
677 #endif
678