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
18 struct workqueue_struct;
19
20 struct work_struct;
21 typedef void (*work_func_t)(struct work_struct *work);
22 void 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
30 enum {
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 WORK_OFFQ_CANCELING = (1 << __WORK_OFFQ_CANCELING),
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 WORK_OFFQ_POOL_NONE = (1LU << WORK_OFFQ_POOL_BITS) - 1,
83
84 /* convenience constants */
85 WORK_STRUCT_FLAG_MASK = (1UL << WORK_STRUCT_FLAG_BITS) - 1,
86 WORK_STRUCT_WQ_DATA_MASK = ~WORK_STRUCT_FLAG_MASK,
87 WORK_STRUCT_NO_POOL = (unsigned long)WORK_OFFQ_POOL_NONE << WORK_OFFQ_POOL_SHIFT,
88
89 /* bit mask for work_busy() return values */
90 WORK_BUSY_PENDING = 1 << 0,
91 WORK_BUSY_RUNNING = 1 << 1,
92
93 /* maximum string length for set_worker_desc() */
94 WORKER_DESC_LEN = 24,
95 };
96
97 struct work_struct {
98 atomic_long_t data;
99 struct list_head entry;
100 work_func_t func;
101 #ifdef CONFIG_LOCKDEP
102 struct lockdep_map lockdep_map;
103 #endif
104 };
105
106 #define WORK_DATA_INIT() ATOMIC_LONG_INIT((unsigned long)WORK_STRUCT_NO_POOL)
107 #define WORK_DATA_STATIC_INIT() \
108 ATOMIC_LONG_INIT((unsigned long)(WORK_STRUCT_NO_POOL | WORK_STRUCT_STATIC))
109
110 struct delayed_work {
111 struct work_struct work;
112 struct timer_list timer;
113
114 /* target workqueue and CPU ->timer uses to queue ->work */
115 struct workqueue_struct *wq;
116 int cpu;
117 };
118
119 struct rcu_work {
120 struct work_struct work;
121 struct rcu_head rcu;
122
123 /* target workqueue ->rcu uses to queue ->work */
124 struct workqueue_struct *wq;
125 };
126
127 /**
128 * struct workqueue_attrs - A struct for workqueue attributes.
129 *
130 * This can be used to change attributes of an unbound workqueue.
131 */
132 struct workqueue_attrs {
133 /**
134 * @nice: nice level
135 */
136 int nice;
137
138 /**
139 * @cpumask: allowed CPUs
140 */
141 cpumask_var_t cpumask;
142
143 /**
144 * @no_numa: disable NUMA affinity
145 *
146 * Unlike other fields, ``no_numa`` isn't a property of a worker_pool. It
147 * only modifies how :c:func:`apply_workqueue_attrs` select pools and thus
148 * doesn't participate in pool hash calculations or equality comparisons.
149 */
150 bool no_numa;
151 };
152
to_delayed_work(struct work_struct * work)153 static inline struct delayed_work *to_delayed_work(struct work_struct *work)
154 {
155 return container_of(work, struct delayed_work, work);
156 }
157
to_rcu_work(struct work_struct * work)158 static inline struct rcu_work *to_rcu_work(struct work_struct *work)
159 {
160 return container_of(work, struct rcu_work, work);
161 }
162
163 struct execute_work {
164 struct work_struct work;
165 };
166
167 #ifdef CONFIG_LOCKDEP
168 /*
169 * NB: because we have to copy the lockdep_map, setting _key
170 * here is required, otherwise it could get initialised to the
171 * copy of the lockdep_map!
172 */
173 #define __WORK_INIT_LOCKDEP_MAP(n, k) \
174 .lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k),
175 #else
176 #define __WORK_INIT_LOCKDEP_MAP(n, k)
177 #endif
178
179 #define __WORK_INITIALIZER(n, f) { \
180 .data = WORK_DATA_STATIC_INIT(), \
181 .entry = { &(n).entry, &(n).entry }, \
182 .func = (f), \
183 __WORK_INIT_LOCKDEP_MAP(#n, &(n)) \
184 }
185
186 #define __DELAYED_WORK_INITIALIZER(n, f, tflags) { \
187 .work = __WORK_INITIALIZER((n).work, (f)), \
188 .timer = __TIMER_INITIALIZER(delayed_work_timer_fn,\
189 (tflags) | TIMER_IRQSAFE), \
190 }
191
192 #define DECLARE_WORK(n, f) \
193 struct work_struct n = __WORK_INITIALIZER(n, f)
194
195 #define DECLARE_DELAYED_WORK(n, f) \
196 struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, 0)
197
198 #define DECLARE_DEFERRABLE_WORK(n, f) \
199 struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, TIMER_DEFERRABLE)
200
201 #ifdef CONFIG_DEBUG_OBJECTS_WORK
202 extern void __init_work(struct work_struct *work, int onstack);
203 extern void destroy_work_on_stack(struct work_struct *work);
204 extern void destroy_delayed_work_on_stack(struct delayed_work *work);
work_static(struct work_struct * work)205 static inline unsigned int work_static(struct work_struct *work)
206 {
207 return *work_data_bits(work) & WORK_STRUCT_STATIC;
208 }
209 #else
__init_work(struct work_struct * work,int onstack)210 static inline void __init_work(struct work_struct *work, int onstack) { }
destroy_work_on_stack(struct work_struct * work)211 static inline void destroy_work_on_stack(struct work_struct *work) { }
destroy_delayed_work_on_stack(struct delayed_work * work)212 static inline void destroy_delayed_work_on_stack(struct delayed_work *work) { }
work_static(struct work_struct * work)213 static inline unsigned int work_static(struct work_struct *work) { return 0; }
214 #endif
215
216 /*
217 * initialize all of a work item in one go
218 *
219 * NOTE! No point in using "atomic_long_set()": using a direct
220 * assignment of the work data initializer allows the compiler
221 * to generate better code.
222 */
223 #ifdef CONFIG_LOCKDEP
224 #define __INIT_WORK(_work, _func, _onstack) \
225 do { \
226 static struct lock_class_key __key; \
227 \
228 __init_work((_work), _onstack); \
229 (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
230 lockdep_init_map(&(_work)->lockdep_map, "(work_completion)"#_work, &__key, 0); \
231 INIT_LIST_HEAD(&(_work)->entry); \
232 (_work)->func = (_func); \
233 } while (0)
234 #else
235 #define __INIT_WORK(_work, _func, _onstack) \
236 do { \
237 __init_work((_work), _onstack); \
238 (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
239 INIT_LIST_HEAD(&(_work)->entry); \
240 (_work)->func = (_func); \
241 } while (0)
242 #endif
243
244 #define INIT_WORK(_work, _func) \
245 __INIT_WORK((_work), (_func), 0)
246
247 #define INIT_WORK_ONSTACK(_work, _func) \
248 __INIT_WORK((_work), (_func), 1)
249
250 #define __INIT_DELAYED_WORK(_work, _func, _tflags) \
251 do { \
252 INIT_WORK(&(_work)->work, (_func)); \
253 __init_timer(&(_work)->timer, \
254 delayed_work_timer_fn, \
255 (_tflags) | TIMER_IRQSAFE); \
256 } while (0)
257
258 #define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags) \
259 do { \
260 INIT_WORK_ONSTACK(&(_work)->work, (_func)); \
261 __init_timer_on_stack(&(_work)->timer, \
262 delayed_work_timer_fn, \
263 (_tflags) | TIMER_IRQSAFE); \
264 } while (0)
265
266 #define INIT_DELAYED_WORK(_work, _func) \
267 __INIT_DELAYED_WORK(_work, _func, 0)
268
269 #define INIT_DELAYED_WORK_ONSTACK(_work, _func) \
270 __INIT_DELAYED_WORK_ONSTACK(_work, _func, 0)
271
272 #define INIT_DEFERRABLE_WORK(_work, _func) \
273 __INIT_DELAYED_WORK(_work, _func, TIMER_DEFERRABLE)
274
275 #define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func) \
276 __INIT_DELAYED_WORK_ONSTACK(_work, _func, TIMER_DEFERRABLE)
277
278 #define INIT_RCU_WORK(_work, _func) \
279 INIT_WORK(&(_work)->work, (_func))
280
281 #define INIT_RCU_WORK_ONSTACK(_work, _func) \
282 INIT_WORK_ONSTACK(&(_work)->work, (_func))
283
284 /**
285 * work_pending - Find out whether a work item is currently pending
286 * @work: The work item in question
287 */
288 #define work_pending(work) \
289 test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
290
291 /**
292 * delayed_work_pending - Find out whether a delayable work item is currently
293 * pending
294 * @w: The work item in question
295 */
296 #define delayed_work_pending(w) \
297 work_pending(&(w)->work)
298
299 /*
300 * Workqueue flags and constants. For details, please refer to
301 * Documentation/core-api/workqueue.rst.
302 */
303 enum {
304 WQ_UNBOUND = 1 << 1, /* not bound to any cpu */
305 WQ_FREEZABLE = 1 << 2, /* freeze during suspend */
306 WQ_MEM_RECLAIM = 1 << 3, /* may be used for memory reclaim */
307 WQ_HIGHPRI = 1 << 4, /* high priority */
308 WQ_CPU_INTENSIVE = 1 << 5, /* cpu intensive workqueue */
309 WQ_SYSFS = 1 << 6, /* visible in sysfs, see workqueue_sysfs_register() */
310
311 /*
312 * Per-cpu workqueues are generally preferred because they tend to
313 * show better performance thanks to cache locality. Per-cpu
314 * workqueues exclude the scheduler from choosing the CPU to
315 * execute the worker threads, which has an unfortunate side effect
316 * of increasing power consumption.
317 *
318 * The scheduler considers a CPU idle if it doesn't have any task
319 * to execute and tries to keep idle cores idle to conserve power;
320 * however, for example, a per-cpu work item scheduled from an
321 * interrupt handler on an idle CPU will force the scheduler to
322 * execute the work item on that CPU breaking the idleness, which in
323 * turn may lead to more scheduling choices which are sub-optimal
324 * in terms of power consumption.
325 *
326 * Workqueues marked with WQ_POWER_EFFICIENT are per-cpu by default
327 * but become unbound if workqueue.power_efficient kernel param is
328 * specified. Per-cpu workqueues which are identified to
329 * contribute significantly to power-consumption are identified and
330 * marked with this flag and enabling the power_efficient mode
331 * leads to noticeable power saving at the cost of small
332 * performance disadvantage.
333 *
334 * http://thread.gmane.org/gmane.linux.kernel/1480396
335 */
336 WQ_POWER_EFFICIENT = 1 << 7,
337
338 __WQ_DESTROYING = 1 << 15, /* internal: workqueue is destroying */
339 __WQ_DRAINING = 1 << 16, /* internal: workqueue is draining */
340 __WQ_ORDERED = 1 << 17, /* internal: workqueue is ordered */
341 __WQ_LEGACY = 1 << 18, /* internal: create*_workqueue() */
342 __WQ_ORDERED_EXPLICIT = 1 << 19, /* internal: alloc_ordered_workqueue() */
343
344 WQ_MAX_ACTIVE = 512, /* I like 512, better ideas? */
345 WQ_MAX_UNBOUND_PER_CPU = 4, /* 4 * #cpus for unbound wq */
346 WQ_DFL_ACTIVE = WQ_MAX_ACTIVE / 2,
347 };
348
349 /* unbound wq's aren't per-cpu, scale max_active according to #cpus */
350 #define WQ_UNBOUND_MAX_ACTIVE \
351 max_t(int, WQ_MAX_ACTIVE, num_possible_cpus() * WQ_MAX_UNBOUND_PER_CPU)
352
353 /*
354 * System-wide workqueues which are always present.
355 *
356 * system_wq is the one used by schedule[_delayed]_work[_on]().
357 * Multi-CPU multi-threaded. There are users which expect relatively
358 * short queue flush time. Don't queue works which can run for too
359 * long.
360 *
361 * system_highpri_wq is similar to system_wq but for work items which
362 * require WQ_HIGHPRI.
363 *
364 * system_long_wq is similar to system_wq but may host long running
365 * works. Queue flushing might take relatively long.
366 *
367 * system_unbound_wq is unbound workqueue. Workers are not bound to
368 * any specific CPU, not concurrency managed, and all queued works are
369 * executed immediately as long as max_active limit is not reached and
370 * resources are available.
371 *
372 * system_freezable_wq is equivalent to system_wq except that it's
373 * freezable.
374 *
375 * *_power_efficient_wq are inclined towards saving power and converted
376 * into WQ_UNBOUND variants if 'wq_power_efficient' is enabled; otherwise,
377 * they are same as their non-power-efficient counterparts - e.g.
378 * system_power_efficient_wq is identical to system_wq if
379 * 'wq_power_efficient' is disabled. See WQ_POWER_EFFICIENT for more info.
380 */
381 extern struct workqueue_struct *system_wq;
382 extern struct workqueue_struct *system_highpri_wq;
383 extern struct workqueue_struct *system_long_wq;
384 extern struct workqueue_struct *system_unbound_wq;
385 extern struct workqueue_struct *system_freezable_wq;
386 extern struct workqueue_struct *system_power_efficient_wq;
387 extern struct workqueue_struct *system_freezable_power_efficient_wq;
388
389 /**
390 * alloc_workqueue - allocate a workqueue
391 * @fmt: printf format for the name of the workqueue
392 * @flags: WQ_* flags
393 * @max_active: max in-flight work items, 0 for default
394 * remaining args: args for @fmt
395 *
396 * Allocate a workqueue with the specified parameters. For detailed
397 * information on WQ_* flags, please refer to
398 * Documentation/core-api/workqueue.rst.
399 *
400 * RETURNS:
401 * Pointer to the allocated workqueue on success, %NULL on failure.
402 */
403 __printf(1, 4) struct workqueue_struct *
404 alloc_workqueue(const char *fmt, unsigned int flags, int max_active, ...);
405
406 /**
407 * alloc_ordered_workqueue - allocate an ordered workqueue
408 * @fmt: printf format for the name of the workqueue
409 * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
410 * @args: args for @fmt
411 *
412 * Allocate an ordered workqueue. An ordered workqueue executes at
413 * most one work item at any given time in the queued order. They are
414 * implemented as unbound workqueues with @max_active of one.
415 *
416 * RETURNS:
417 * Pointer to the allocated workqueue on success, %NULL on failure.
418 */
419 #define alloc_ordered_workqueue(fmt, flags, args...) \
420 alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | \
421 __WQ_ORDERED_EXPLICIT | (flags), 1, ##args)
422
423 #define create_workqueue(name) \
424 alloc_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, 1, (name))
425 #define create_freezable_workqueue(name) \
426 alloc_workqueue("%s", __WQ_LEGACY | WQ_FREEZABLE | WQ_UNBOUND | \
427 WQ_MEM_RECLAIM, 1, (name))
428 #define create_singlethread_workqueue(name) \
429 alloc_ordered_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, name)
430
431 extern void destroy_workqueue(struct workqueue_struct *wq);
432
433 struct workqueue_attrs *alloc_workqueue_attrs(void);
434 void free_workqueue_attrs(struct workqueue_attrs *attrs);
435 int apply_workqueue_attrs(struct workqueue_struct *wq,
436 const struct workqueue_attrs *attrs);
437 int workqueue_set_unbound_cpumask(cpumask_var_t cpumask);
438
439 extern bool queue_work_on(int cpu, struct workqueue_struct *wq,
440 struct work_struct *work);
441 extern bool queue_work_node(int node, struct workqueue_struct *wq,
442 struct work_struct *work);
443 extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
444 struct delayed_work *work, unsigned long delay);
445 extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
446 struct delayed_work *dwork, unsigned long delay);
447 extern bool queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork);
448
449 extern void __flush_workqueue(struct workqueue_struct *wq);
450 extern void drain_workqueue(struct workqueue_struct *wq);
451
452 extern int schedule_on_each_cpu(work_func_t func);
453
454 int execute_in_process_context(work_func_t fn, struct execute_work *);
455
456 extern bool flush_work(struct work_struct *work);
457 extern bool cancel_work(struct work_struct *work);
458 extern bool cancel_work_sync(struct work_struct *work);
459
460 extern bool flush_delayed_work(struct delayed_work *dwork);
461 extern bool cancel_delayed_work(struct delayed_work *dwork);
462 extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
463
464 extern bool flush_rcu_work(struct rcu_work *rwork);
465
466 extern void workqueue_set_max_active(struct workqueue_struct *wq,
467 int max_active);
468 extern struct work_struct *current_work(void);
469 extern bool current_is_workqueue_rescuer(void);
470 extern bool workqueue_congested(int cpu, struct workqueue_struct *wq);
471 extern unsigned int work_busy(struct work_struct *work);
472 extern __printf(1, 2) void set_worker_desc(const char *fmt, ...);
473 extern void print_worker_info(const char *log_lvl, struct task_struct *task);
474 extern void show_all_workqueues(void);
475 extern void show_one_workqueue(struct workqueue_struct *wq);
476 extern void wq_worker_comm(char *buf, size_t size, struct task_struct *task);
477
478 /**
479 * queue_work - queue work on a workqueue
480 * @wq: workqueue to use
481 * @work: work to queue
482 *
483 * Returns %false if @work was already on a queue, %true otherwise.
484 *
485 * We queue the work to the CPU on which it was submitted, but if the CPU dies
486 * it can be processed by another CPU.
487 *
488 * Memory-ordering properties: If it returns %true, guarantees that all stores
489 * preceding the call to queue_work() in the program order will be visible from
490 * the CPU which will execute @work by the time such work executes, e.g.,
491 *
492 * { x is initially 0 }
493 *
494 * CPU0 CPU1
495 *
496 * WRITE_ONCE(x, 1); [ @work is being executed ]
497 * r0 = queue_work(wq, work); r1 = READ_ONCE(x);
498 *
499 * Forbids: r0 == true && r1 == 0
500 */
queue_work(struct workqueue_struct * wq,struct work_struct * work)501 static inline bool queue_work(struct workqueue_struct *wq,
502 struct work_struct *work)
503 {
504 return queue_work_on(WORK_CPU_UNBOUND, wq, work);
505 }
506
507 /**
508 * queue_delayed_work - queue work on a workqueue after delay
509 * @wq: workqueue to use
510 * @dwork: delayable work to queue
511 * @delay: number of jiffies to wait before queueing
512 *
513 * Equivalent to queue_delayed_work_on() but tries to use the local CPU.
514 */
queue_delayed_work(struct workqueue_struct * wq,struct delayed_work * dwork,unsigned long delay)515 static inline bool queue_delayed_work(struct workqueue_struct *wq,
516 struct delayed_work *dwork,
517 unsigned long delay)
518 {
519 return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
520 }
521
522 /**
523 * mod_delayed_work - modify delay of or queue a delayed work
524 * @wq: workqueue to use
525 * @dwork: work to queue
526 * @delay: number of jiffies to wait before queueing
527 *
528 * mod_delayed_work_on() on local CPU.
529 */
mod_delayed_work(struct workqueue_struct * wq,struct delayed_work * dwork,unsigned long delay)530 static inline bool mod_delayed_work(struct workqueue_struct *wq,
531 struct delayed_work *dwork,
532 unsigned long delay)
533 {
534 return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
535 }
536
537 /**
538 * schedule_work_on - put work task on a specific cpu
539 * @cpu: cpu to put the work task on
540 * @work: job to be done
541 *
542 * This puts a job on a specific cpu
543 */
schedule_work_on(int cpu,struct work_struct * work)544 static inline bool schedule_work_on(int cpu, struct work_struct *work)
545 {
546 return queue_work_on(cpu, system_wq, work);
547 }
548
549 /**
550 * schedule_work - put work task in global workqueue
551 * @work: job to be done
552 *
553 * Returns %false if @work was already on the kernel-global workqueue and
554 * %true otherwise.
555 *
556 * This puts a job in the kernel-global workqueue if it was not already
557 * queued and leaves it in the same position on the kernel-global
558 * workqueue otherwise.
559 *
560 * Shares the same memory-ordering properties of queue_work(), cf. the
561 * DocBook header of queue_work().
562 */
schedule_work(struct work_struct * work)563 static inline bool schedule_work(struct work_struct *work)
564 {
565 return queue_work(system_wq, work);
566 }
567
568 /*
569 * Detect attempt to flush system-wide workqueues at compile time when possible.
570 *
571 * See https://lkml.kernel.org/r/49925af7-78a8-a3dd-bce6-cfc02e1a9236@I-love.SAKURA.ne.jp
572 * for reasons and steps for converting system-wide workqueues into local workqueues.
573 */
574 extern void __warn_flushing_systemwide_wq(void)
575 __compiletime_warning("Please avoid flushing system-wide workqueues.");
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 * It's very easy to get into trouble if you don't take great care.
584 * Either of the following situations will lead to deadlock:
585 *
586 * One of the work items currently on the workqueue needs to acquire
587 * a lock held by your code or its caller.
588 *
589 * Your code is running in the context of a work routine.
590 *
591 * They will be detected by lockdep when they occur, but the first might not
592 * occur very often. It depends on what work items are on the workqueue and
593 * what locks they need, which you have no control over.
594 *
595 * In most situations flushing the entire workqueue is overkill; you merely
596 * need to know that a particular work item isn't queued and isn't running.
597 * In such cases you should use cancel_delayed_work_sync() or
598 * cancel_work_sync() instead.
599 *
600 * Please stop calling this function! A conversion to stop flushing system-wide
601 * workqueues is in progress. This function will be removed after all in-tree
602 * users stopped calling this function.
603 */
604 /*
605 * The background of commit 771c035372a036f8 ("deprecate the
606 * '__deprecated' attribute warnings entirely and for good") is that,
607 * since Linus builds all modules between every single pull he does,
608 * the standard kernel build needs to be _clean_ in order to be able to
609 * notice when new problems happen. Therefore, don't emit warning while
610 * there are in-tree users.
611 */
612 #define flush_scheduled_work() \
613 ({ \
614 if (0) \
615 __warn_flushing_systemwide_wq(); \
616 __flush_workqueue(system_wq); \
617 })
618
619 /*
620 * Although there is no longer in-tree caller, for now just emit warning
621 * in order to give out-of-tree callers time to update.
622 */
623 #define flush_workqueue(wq) \
624 ({ \
625 struct workqueue_struct *_wq = (wq); \
626 \
627 if ((__builtin_constant_p(_wq == system_wq) && \
628 _wq == system_wq) || \
629 (__builtin_constant_p(_wq == system_highpri_wq) && \
630 _wq == system_highpri_wq) || \
631 (__builtin_constant_p(_wq == system_long_wq) && \
632 _wq == system_long_wq) || \
633 (__builtin_constant_p(_wq == system_unbound_wq) && \
634 _wq == system_unbound_wq) || \
635 (__builtin_constant_p(_wq == system_freezable_wq) && \
636 _wq == system_freezable_wq) || \
637 (__builtin_constant_p(_wq == system_power_efficient_wq) && \
638 _wq == system_power_efficient_wq) || \
639 (__builtin_constant_p(_wq == system_freezable_power_efficient_wq) && \
640 _wq == system_freezable_power_efficient_wq)) \
641 __warn_flushing_systemwide_wq(); \
642 __flush_workqueue(_wq); \
643 })
644
645 /**
646 * schedule_delayed_work_on - queue work in global workqueue on CPU after delay
647 * @cpu: cpu to use
648 * @dwork: job to be done
649 * @delay: number of jiffies to wait
650 *
651 * After waiting for a given time this puts a job in the kernel-global
652 * workqueue on the specified CPU.
653 */
schedule_delayed_work_on(int cpu,struct delayed_work * dwork,unsigned long delay)654 static inline bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork,
655 unsigned long delay)
656 {
657 return queue_delayed_work_on(cpu, system_wq, dwork, delay);
658 }
659
660 /**
661 * schedule_delayed_work - put work task in global workqueue after delay
662 * @dwork: job to be done
663 * @delay: number of jiffies to wait or 0 for immediate execution
664 *
665 * After waiting for a given time this puts a job in the kernel-global
666 * workqueue.
667 */
schedule_delayed_work(struct delayed_work * dwork,unsigned long delay)668 static inline bool schedule_delayed_work(struct delayed_work *dwork,
669 unsigned long delay)
670 {
671 return queue_delayed_work(system_wq, dwork, delay);
672 }
673
674 #ifndef CONFIG_SMP
work_on_cpu(int cpu,long (* fn)(void *),void * arg)675 static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
676 {
677 return fn(arg);
678 }
work_on_cpu_safe(int cpu,long (* fn)(void *),void * arg)679 static inline long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg)
680 {
681 return fn(arg);
682 }
683 #else
684 long work_on_cpu(int cpu, long (*fn)(void *), void *arg);
685 long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg);
686 #endif /* CONFIG_SMP */
687
688 #ifdef CONFIG_FREEZER
689 extern void freeze_workqueues_begin(void);
690 extern bool freeze_workqueues_busy(void);
691 extern void thaw_workqueues(void);
692 #endif /* CONFIG_FREEZER */
693
694 #ifdef CONFIG_SYSFS
695 int workqueue_sysfs_register(struct workqueue_struct *wq);
696 #else /* CONFIG_SYSFS */
workqueue_sysfs_register(struct workqueue_struct * wq)697 static inline int workqueue_sysfs_register(struct workqueue_struct *wq)
698 { return 0; }
699 #endif /* CONFIG_SYSFS */
700
701 #ifdef CONFIG_WQ_WATCHDOG
702 void wq_watchdog_touch(int cpu);
703 #else /* CONFIG_WQ_WATCHDOG */
wq_watchdog_touch(int cpu)704 static inline void wq_watchdog_touch(int cpu) { }
705 #endif /* CONFIG_WQ_WATCHDOG */
706
707 #ifdef CONFIG_SMP
708 int workqueue_prepare_cpu(unsigned int cpu);
709 int workqueue_online_cpu(unsigned int cpu);
710 int workqueue_offline_cpu(unsigned int cpu);
711 #endif
712
713 void __init workqueue_init_early(void);
714 void __init workqueue_init(void);
715
716 #endif
717