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/alloc_tag.h>
10 #include <linux/timer.h>
11 #include <linux/linkage.h>
12 #include <linux/bitops.h>
13 #include <linux/lockdep.h>
14 #include <linux/threads.h>
15 #include <linux/atomic.h>
16 #include <linux/cpumask_types.h>
17 #include <linux/rcupdate.h>
18 #include <linux/workqueue_types.h>
19
20 /*
21 * The first word is the work queue pointer and the flags rolled into
22 * one
23 */
24 #define work_data_bits(work) ((unsigned long *)(&(work)->data))
25
26 enum work_bits {
27 WORK_STRUCT_PENDING_BIT = 0, /* work item is pending execution */
28 WORK_STRUCT_INACTIVE_BIT, /* work item is inactive */
29 WORK_STRUCT_PWQ_BIT, /* data points to pwq */
30 WORK_STRUCT_LINKED_BIT, /* next work is linked to this one */
31 #ifdef CONFIG_DEBUG_OBJECTS_WORK
32 WORK_STRUCT_STATIC_BIT, /* static initializer (debugobjects) */
33 #endif
34 WORK_STRUCT_FLAG_BITS,
35
36 /* color for workqueue flushing */
37 WORK_STRUCT_COLOR_SHIFT = WORK_STRUCT_FLAG_BITS,
38 WORK_STRUCT_COLOR_BITS = 4,
39
40 /*
41 * When WORK_STRUCT_PWQ is set, reserve 8 bits off of pwq pointer w/
42 * debugobjects turned off. This makes pwqs aligned to 256 bytes (512
43 * bytes w/ DEBUG_OBJECTS_WORK) and allows 16 workqueue flush colors.
44 *
45 * MSB
46 * [ pwq pointer ] [ flush color ] [ STRUCT flags ]
47 * 4 bits 4 or 5 bits
48 */
49 WORK_STRUCT_PWQ_SHIFT = WORK_STRUCT_COLOR_SHIFT + WORK_STRUCT_COLOR_BITS,
50
51 /*
52 * data contains off-queue information when !WORK_STRUCT_PWQ.
53 *
54 * MSB
55 * [ pool ID ] [ disable depth ] [ OFFQ flags ] [ STRUCT flags ]
56 * 16 bits 1 bit 4 or 5 bits
57 */
58 WORK_OFFQ_FLAG_SHIFT = WORK_STRUCT_FLAG_BITS,
59 WORK_OFFQ_BH_BIT = WORK_OFFQ_FLAG_SHIFT,
60 WORK_OFFQ_FLAG_END,
61 WORK_OFFQ_FLAG_BITS = WORK_OFFQ_FLAG_END - WORK_OFFQ_FLAG_SHIFT,
62
63 WORK_OFFQ_DISABLE_SHIFT = WORK_OFFQ_FLAG_SHIFT + WORK_OFFQ_FLAG_BITS,
64 WORK_OFFQ_DISABLE_BITS = 16,
65
66 /*
67 * When a work item is off queue, the high bits encode off-queue flags
68 * and the last pool it was on. Cap pool ID to 31 bits and use the
69 * highest number to indicate that no pool is associated.
70 */
71 WORK_OFFQ_POOL_SHIFT = WORK_OFFQ_DISABLE_SHIFT + WORK_OFFQ_DISABLE_BITS,
72 WORK_OFFQ_LEFT = BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT,
73 WORK_OFFQ_POOL_BITS = WORK_OFFQ_LEFT <= 31 ? WORK_OFFQ_LEFT : 31,
74 };
75
76 enum work_flags {
77 WORK_STRUCT_PENDING = 1 << WORK_STRUCT_PENDING_BIT,
78 WORK_STRUCT_INACTIVE = 1 << WORK_STRUCT_INACTIVE_BIT,
79 WORK_STRUCT_PWQ = 1 << WORK_STRUCT_PWQ_BIT,
80 WORK_STRUCT_LINKED = 1 << WORK_STRUCT_LINKED_BIT,
81 #ifdef CONFIG_DEBUG_OBJECTS_WORK
82 WORK_STRUCT_STATIC = 1 << WORK_STRUCT_STATIC_BIT,
83 #else
84 WORK_STRUCT_STATIC = 0,
85 #endif
86 };
87
88 enum wq_misc_consts {
89 WORK_NR_COLORS = (1 << WORK_STRUCT_COLOR_BITS),
90
91 /* not bound to any CPU, prefer the local CPU */
92 WORK_CPU_UNBOUND = NR_CPUS,
93
94 /* bit mask for work_busy() return values */
95 WORK_BUSY_PENDING = 1 << 0,
96 WORK_BUSY_RUNNING = 1 << 1,
97
98 /* maximum string length for set_worker_desc() */
99 WORKER_DESC_LEN = 32,
100 };
101
102 /* Convenience constants - of type 'unsigned long', not 'enum'! */
103 #define WORK_OFFQ_BH (1ul << WORK_OFFQ_BH_BIT)
104 #define WORK_OFFQ_FLAG_MASK (((1ul << WORK_OFFQ_FLAG_BITS) - 1) << WORK_OFFQ_FLAG_SHIFT)
105 #define WORK_OFFQ_DISABLE_MASK (((1ul << WORK_OFFQ_DISABLE_BITS) - 1) << WORK_OFFQ_DISABLE_SHIFT)
106 #define WORK_OFFQ_POOL_NONE ((1ul << WORK_OFFQ_POOL_BITS) - 1)
107 #define WORK_STRUCT_NO_POOL (WORK_OFFQ_POOL_NONE << WORK_OFFQ_POOL_SHIFT)
108 #define WORK_STRUCT_PWQ_MASK (~((1ul << WORK_STRUCT_PWQ_SHIFT) - 1))
109
110 #define WORK_DATA_INIT() ATOMIC_LONG_INIT((unsigned long)WORK_STRUCT_NO_POOL)
111 #define WORK_DATA_STATIC_INIT() \
112 ATOMIC_LONG_INIT((unsigned long)(WORK_STRUCT_NO_POOL | WORK_STRUCT_STATIC))
113
114 struct delayed_work {
115 struct work_struct work;
116 struct timer_list timer;
117
118 /* target workqueue and CPU ->timer uses to queue ->work */
119 struct workqueue_struct *wq;
120 int cpu;
121 };
122
123 struct rcu_work {
124 struct work_struct work;
125 struct rcu_head rcu;
126
127 /* target workqueue ->rcu uses to queue ->work */
128 struct workqueue_struct *wq;
129 };
130
131 enum wq_affn_scope {
132 WQ_AFFN_DFL, /* use system default */
133 WQ_AFFN_CPU, /* one pod per CPU */
134 WQ_AFFN_SMT, /* one pod per SMT */
135 WQ_AFFN_CACHE, /* one pod per LLC */
136 WQ_AFFN_CACHE_SHARD, /* synthetic sub-LLC shards */
137 WQ_AFFN_NUMA, /* one pod per NUMA node */
138 WQ_AFFN_SYSTEM, /* one pod across the whole system */
139
140 WQ_AFFN_NR_TYPES,
141 };
142
143 /**
144 * struct workqueue_attrs - A struct for workqueue attributes.
145 *
146 * This can be used to change attributes of an unbound workqueue.
147 */
148 struct workqueue_attrs {
149 /**
150 * @nice: nice level
151 */
152 int nice;
153
154 /**
155 * @cpumask: allowed CPUs
156 *
157 * Work items in this workqueue are affine to these CPUs and not allowed
158 * to execute on other CPUs. A pool serving a workqueue must have the
159 * same @cpumask.
160 */
161 cpumask_var_t cpumask;
162
163 /**
164 * @__pod_cpumask: internal attribute used to create per-pod pools
165 *
166 * Internal use only.
167 *
168 * Per-pod unbound worker pools are used to improve locality. Always a
169 * subset of ->cpumask. A workqueue can be associated with multiple
170 * worker pools with disjoint @__pod_cpumask's. Whether the enforcement
171 * of a pool's @__pod_cpumask is strict depends on @affn_strict.
172 */
173 cpumask_var_t __pod_cpumask;
174
175 /**
176 * @affn_strict: affinity scope is strict
177 *
178 * If clear, workqueue will make a best-effort attempt at starting the
179 * worker inside @__pod_cpumask but the scheduler is free to migrate it
180 * outside.
181 *
182 * If set, workers are only allowed to run inside @__pod_cpumask.
183 */
184 bool affn_strict;
185
186 /*
187 * Below fields aren't properties of a worker_pool. They only modify how
188 * :c:func:`apply_workqueue_attrs` select pools and thus don't
189 * participate in pool hash calculations or equality comparisons.
190 *
191 * If @affn_strict is set, @cpumask isn't a property of a worker_pool
192 * either.
193 */
194
195 /**
196 * @affn_scope: unbound CPU affinity scope
197 *
198 * CPU pods are used to improve execution locality of unbound work
199 * items. There are multiple pod types, one for each wq_affn_scope, and
200 * every CPU in the system belongs to one pod in every pod type. CPUs
201 * that belong to the same pod share the worker pool. For example,
202 * selecting %WQ_AFFN_NUMA makes the workqueue use a separate worker
203 * pool for each NUMA node.
204 */
205 enum wq_affn_scope affn_scope;
206
207 /**
208 * @ordered: work items must be executed one by one in queueing order
209 */
210 bool ordered;
211 };
212
to_delayed_work(struct work_struct * work)213 static inline struct delayed_work *to_delayed_work(struct work_struct *work)
214 {
215 return container_of(work, struct delayed_work, work);
216 }
217
to_rcu_work(struct work_struct * work)218 static inline struct rcu_work *to_rcu_work(struct work_struct *work)
219 {
220 return container_of(work, struct rcu_work, work);
221 }
222
223 struct execute_work {
224 struct work_struct work;
225 };
226
227 #ifdef CONFIG_LOCKDEP
228 /*
229 * NB: because we have to copy the lockdep_map, setting _key
230 * here is required, otherwise it could get initialised to the
231 * copy of the lockdep_map!
232 */
233 #define __WORK_INIT_LOCKDEP_MAP(n, k) \
234 .lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k),
235 #else
236 #define __WORK_INIT_LOCKDEP_MAP(n, k)
237 #endif
238
239 #define __WORK_INITIALIZER(n, f) { \
240 .data = WORK_DATA_STATIC_INIT(), \
241 .entry = { &(n).entry, &(n).entry }, \
242 .func = (f), \
243 __WORK_INIT_LOCKDEP_MAP(#n, &(n)) \
244 }
245
246 #define __DELAYED_WORK_INITIALIZER(n, f, tflags) { \
247 .work = __WORK_INITIALIZER((n).work, (f)), \
248 .timer = __TIMER_INITIALIZER(delayed_work_timer_fn,\
249 (tflags) | TIMER_IRQSAFE), \
250 }
251
252 #define DECLARE_WORK(n, f) \
253 struct work_struct n = __WORK_INITIALIZER(n, f)
254
255 #define DECLARE_DELAYED_WORK(n, f) \
256 struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, 0)
257
258 #define DECLARE_DEFERRABLE_WORK(n, f) \
259 struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, TIMER_DEFERRABLE)
260
261 #ifdef CONFIG_DEBUG_OBJECTS_WORK
262 extern void __init_work(struct work_struct *work, int onstack);
263 extern void destroy_work_on_stack(struct work_struct *work);
264 extern void destroy_delayed_work_on_stack(struct delayed_work *work);
work_static(struct work_struct * work)265 static inline unsigned int work_static(struct work_struct *work)
266 {
267 return *work_data_bits(work) & WORK_STRUCT_STATIC;
268 }
269 #else
__init_work(struct work_struct * work,int onstack)270 static inline void __init_work(struct work_struct *work, int onstack) { }
destroy_work_on_stack(struct work_struct * work)271 static inline void destroy_work_on_stack(struct work_struct *work) { }
destroy_delayed_work_on_stack(struct delayed_work * work)272 static inline void destroy_delayed_work_on_stack(struct delayed_work *work) { }
work_static(struct work_struct * work)273 static inline unsigned int work_static(struct work_struct *work) { return 0; }
274 #endif
275
276 /*
277 * initialize all of a work item in one go
278 *
279 * NOTE! No point in using "atomic_long_set()": using a direct
280 * assignment of the work data initializer allows the compiler
281 * to generate better code.
282 */
283 #ifdef CONFIG_LOCKDEP
284 #define __INIT_WORK_KEY(_work, _func, _onstack, _key) \
285 do { \
286 __init_work((_work), _onstack); \
287 (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
288 lockdep_init_map(&(_work)->lockdep_map, "(work_completion)"#_work, (_key), 0); \
289 INIT_LIST_HEAD(&(_work)->entry); \
290 (_work)->func = (_func); \
291 } while (0)
292 #else
293 #define __INIT_WORK_KEY(_work, _func, _onstack, _key) \
294 do { \
295 __init_work((_work), _onstack); \
296 (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
297 INIT_LIST_HEAD(&(_work)->entry); \
298 (_work)->func = (_func); \
299 } while (0)
300 #endif
301
302 #define __INIT_WORK(_work, _func, _onstack) \
303 do { \
304 static __maybe_unused struct lock_class_key __key; \
305 \
306 __INIT_WORK_KEY(_work, _func, _onstack, &__key); \
307 } while (0)
308
309 #define INIT_WORK(_work, _func) \
310 __INIT_WORK((_work), (_func), 0)
311
312 #define INIT_WORK_ONSTACK(_work, _func) \
313 __INIT_WORK((_work), (_func), 1)
314
315 #define INIT_WORK_ONSTACK_KEY(_work, _func, _key) \
316 __INIT_WORK_KEY((_work), (_func), 1, _key)
317
318 #define __INIT_DELAYED_WORK(_work, _func, _tflags) \
319 do { \
320 INIT_WORK(&(_work)->work, (_func)); \
321 __timer_init(&(_work)->timer, \
322 delayed_work_timer_fn, \
323 (_tflags) | TIMER_IRQSAFE); \
324 } while (0)
325
326 #define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags) \
327 do { \
328 INIT_WORK_ONSTACK(&(_work)->work, (_func)); \
329 __timer_init_on_stack(&(_work)->timer, \
330 delayed_work_timer_fn, \
331 (_tflags) | TIMER_IRQSAFE); \
332 } while (0)
333
334 #define INIT_DELAYED_WORK(_work, _func) \
335 __INIT_DELAYED_WORK(_work, _func, 0)
336
337 #define INIT_DELAYED_WORK_ONSTACK(_work, _func) \
338 __INIT_DELAYED_WORK_ONSTACK(_work, _func, 0)
339
340 #define INIT_DEFERRABLE_WORK(_work, _func) \
341 __INIT_DELAYED_WORK(_work, _func, TIMER_DEFERRABLE)
342
343 #define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func) \
344 __INIT_DELAYED_WORK_ONSTACK(_work, _func, TIMER_DEFERRABLE)
345
346 #define INIT_RCU_WORK(_work, _func) \
347 INIT_WORK(&(_work)->work, (_func))
348
349 #define INIT_RCU_WORK_ONSTACK(_work, _func) \
350 INIT_WORK_ONSTACK(&(_work)->work, (_func))
351
352 /**
353 * work_pending - Find out whether a work item is currently pending
354 * @work: The work item in question
355 */
356 #define work_pending(work) \
357 test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
358
359 /**
360 * delayed_work_pending - Find out whether a delayable work item is currently
361 * pending
362 * @w: The work item in question
363 */
364 #define delayed_work_pending(w) \
365 work_pending(&(w)->work)
366
367 /*
368 * Workqueue flags and constants. For details, please refer to
369 * Documentation/core-api/workqueue.rst.
370 */
371 enum wq_flags {
372 WQ_BH = 1 << 0, /* execute in bottom half (softirq) context */
373 WQ_UNBOUND = 1 << 1, /* not bound to any cpu */
374 WQ_FREEZABLE = 1 << 2, /* freeze during suspend */
375 WQ_MEM_RECLAIM = 1 << 3, /* may be used for memory reclaim */
376 WQ_HIGHPRI = 1 << 4, /* high priority */
377 WQ_CPU_INTENSIVE = 1 << 5, /* cpu intensive workqueue */
378 WQ_SYSFS = 1 << 6, /* visible in sysfs, see workqueue_sysfs_register() */
379
380 /*
381 * Per-cpu workqueues are generally preferred because they tend to
382 * show better performance thanks to cache locality. Per-cpu
383 * workqueues exclude the scheduler from choosing the CPU to
384 * execute the worker threads, which has an unfortunate side effect
385 * of increasing power consumption.
386 *
387 * The scheduler considers a CPU idle if it doesn't have any task
388 * to execute and tries to keep idle cores idle to conserve power;
389 * however, for example, a per-cpu work item scheduled from an
390 * interrupt handler on an idle CPU will force the scheduler to
391 * execute the work item on that CPU breaking the idleness, which in
392 * turn may lead to more scheduling choices which are sub-optimal
393 * in terms of power consumption.
394 *
395 * Workqueues marked with WQ_POWER_EFFICIENT are per-cpu by default
396 * but become unbound if workqueue.power_efficient kernel param is
397 * specified. Per-cpu workqueues which are identified to
398 * contribute significantly to power-consumption are identified and
399 * marked with this flag and enabling the power_efficient mode
400 * leads to noticeable power saving at the cost of small
401 * performance disadvantage.
402 *
403 * http://thread.gmane.org/gmane.linux.kernel/1480396
404 */
405 WQ_POWER_EFFICIENT = 1 << 7,
406 WQ_PERCPU = 1 << 8, /* bound to a specific cpu */
407
408 __WQ_DESTROYING = 1 << 15, /* internal: workqueue is destroying */
409 __WQ_DRAINING = 1 << 16, /* internal: workqueue is draining */
410 __WQ_ORDERED = 1 << 17, /* internal: workqueue is ordered */
411 __WQ_LEGACY = 1 << 18, /* internal: create*_workqueue() */
412 __WQ_DEPRECATED = 1 << 19, /* internal: workqueue is deprecated */
413
414 /* BH wq only allows the following flags */
415 __WQ_BH_ALLOWS = WQ_BH | WQ_HIGHPRI | WQ_PERCPU,
416 };
417
418 enum wq_consts {
419 WQ_MAX_ACTIVE = 2048, /* I like 2048, better ideas? */
420 WQ_UNBOUND_MAX_ACTIVE = WQ_MAX_ACTIVE,
421 WQ_DFL_ACTIVE = WQ_MAX_ACTIVE / 2,
422
423 /*
424 * Per-node default cap on min_active. Unless explicitly set, min_active
425 * is set to min(max_active, WQ_DFL_MIN_ACTIVE). For more details, see
426 * workqueue_struct->min_active definition.
427 */
428 WQ_DFL_MIN_ACTIVE = 8,
429 };
430
431 /*
432 * System-wide workqueues which are always present.
433 *
434 * system_percpu_wq is the one used by schedule[_delayed]_work[_on]().
435 * Multi-CPU multi-threaded. There are users which expect relatively
436 * short queue flush time. Don't queue works which can run for too
437 * long.
438 *
439 * system_highpri_wq is similar to system_percpu_wq but for work items which
440 * require WQ_HIGHPRI.
441 *
442 * system_long_wq is similar to system_percpu_wq but may host long running
443 * works. Queue flushing might take relatively long.
444 *
445 * system_dfl_long_wq is similar to system_dfl_wq but it may host long running
446 * works.
447 *
448 * system_dfl_wq is unbound workqueue. Workers are not bound to
449 * any specific CPU, not concurrency managed, and all queued works are
450 * executed immediately as long as max_active limit is not reached and
451 * resources are available.
452 *
453 * system_freezable_wq is equivalent to system_percpu_wq except that it's
454 * freezable.
455 *
456 * *_power_efficient_wq are inclined towards saving power and converted
457 * into WQ_UNBOUND variants if 'wq_power_efficient' is enabled; otherwise,
458 * they are same as their non-power-efficient counterparts - e.g.
459 * system_power_efficient_wq is identical to system_percpu_wq if
460 * 'wq_power_efficient' is disabled. See WQ_POWER_EFFICIENT for more info.
461 *
462 * system_bh[_highpri]_wq are convenience interface to softirq. BH work items
463 * are executed in the queueing CPU's BH context in the queueing order.
464 */
465 extern struct workqueue_struct *system_wq; /* use system_percpu_wq, this will be removed */
466 extern struct workqueue_struct *system_percpu_wq;
467 extern struct workqueue_struct *system_highpri_wq;
468 extern struct workqueue_struct *system_long_wq;
469 extern struct workqueue_struct *system_unbound_wq;
470 extern struct workqueue_struct *system_dfl_wq;
471 extern struct workqueue_struct *system_freezable_wq;
472 extern struct workqueue_struct *system_power_efficient_wq;
473 extern struct workqueue_struct *system_freezable_power_efficient_wq;
474 extern struct workqueue_struct *system_bh_wq;
475 extern struct workqueue_struct *system_bh_highpri_wq;
476 extern struct workqueue_struct *system_dfl_long_wq;
477
478 void workqueue_softirq_action(bool highpri);
479 void workqueue_softirq_dead(unsigned int cpu);
480
481 /**
482 * alloc_workqueue - allocate a workqueue
483 * @fmt: printf format for the name of the workqueue
484 * @flags: WQ_* flags
485 * @max_active: max in-flight work items, 0 for default
486 * @...: args for @fmt
487 *
488 * For a per-cpu workqueue, @max_active limits the number of in-flight work
489 * items for each CPU. e.g. @max_active of 1 indicates that each CPU can be
490 * executing at most one work item for the workqueue.
491 *
492 * For unbound workqueues, @max_active limits the number of in-flight work items
493 * for the whole system. e.g. @max_active of 16 indicates that there can be
494 * at most 16 work items executing for the workqueue in the whole system.
495 *
496 * As sharing the same active counter for an unbound workqueue across multiple
497 * NUMA nodes can be expensive, @max_active is distributed to each NUMA node
498 * according to the proportion of the number of online CPUs and enforced
499 * independently.
500 *
501 * Depending on online CPU distribution, a node may end up with per-node
502 * max_active which is significantly lower than @max_active, which can lead to
503 * deadlocks if the per-node concurrency limit is lower than the maximum number
504 * of interdependent work items for the workqueue.
505 *
506 * To guarantee forward progress regardless of online CPU distribution, the
507 * concurrency limit on every node is guaranteed to be equal to or greater than
508 * min_active which is set to min(@max_active, %WQ_DFL_MIN_ACTIVE). This means
509 * that the sum of per-node max_active's may be larger than @max_active.
510 *
511 * For detailed information on %WQ_\* flags, please refer to
512 * Documentation/core-api/workqueue.rst.
513 *
514 * RETURNS:
515 * Pointer to the allocated workqueue on success, %NULL on failure.
516 */
517 __printf(1, 4) struct workqueue_struct *
518 alloc_workqueue_noprof(const char *fmt, unsigned int flags, int max_active, ...);
519 #define alloc_workqueue(...) alloc_hooks(alloc_workqueue_noprof(__VA_ARGS__))
520
521 /**
522 * devm_alloc_workqueue - Resource-managed allocate a workqueue
523 * @dev: Device to allocate workqueue for
524 * @fmt: printf format for the name of the workqueue
525 * @flags: WQ_* flags
526 * @max_active: max in-flight work items, 0 for default
527 * @...: args for @fmt
528 *
529 * Resource managed workqueue, see alloc_workqueue() for details.
530 *
531 * The workqueue will be automatically destroyed on driver detach. Typically
532 * this should be used in drivers already relying on devm interafaces.
533 *
534 * RETURNS:
535 * Pointer to the allocated workqueue on success, %NULL on failure.
536 */
537 __printf(2, 5) struct workqueue_struct *
538 devm_alloc_workqueue_noprof(struct device *dev, const char *fmt,
539 unsigned int flags, int max_active, ...);
540 #define devm_alloc_workqueue(...) \
541 alloc_hooks(devm_alloc_workqueue_noprof(__VA_ARGS__))
542
543 #ifdef CONFIG_LOCKDEP
544 /**
545 * alloc_workqueue_lockdep_map - allocate a workqueue with user-defined lockdep_map
546 * @fmt: printf format for the name of the workqueue
547 * @flags: WQ_* flags
548 * @max_active: max in-flight work items, 0 for default
549 * @lockdep_map: user-defined lockdep_map
550 * @...: args for @fmt
551 *
552 * Same as alloc_workqueue but with the a user-define lockdep_map. Useful for
553 * workqueues created with the same purpose and to avoid leaking a lockdep_map
554 * on each workqueue creation.
555 *
556 * RETURNS:
557 * Pointer to the allocated workqueue on success, %NULL on failure.
558 */
559 __printf(1, 5) struct workqueue_struct *
560 alloc_workqueue_lockdep_map(const char *fmt, unsigned int flags, int max_active,
561 struct lockdep_map *lockdep_map, ...);
562
563 /**
564 * alloc_ordered_workqueue_lockdep_map - allocate an ordered workqueue with
565 * user-defined lockdep_map
566 *
567 * @fmt: printf format for the name of the workqueue
568 * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
569 * @lockdep_map: user-defined lockdep_map
570 * @args: args for @fmt
571 *
572 * Same as alloc_ordered_workqueue but with the a user-define lockdep_map.
573 * Useful for workqueues created with the same purpose and to avoid leaking a
574 * lockdep_map on each workqueue creation.
575 *
576 * RETURNS:
577 * Pointer to the allocated workqueue on success, %NULL on failure.
578 */
579 #define alloc_ordered_workqueue_lockdep_map(fmt, flags, lockdep_map, args...) \
580 alloc_hooks(alloc_workqueue_lockdep_map(fmt, WQ_UNBOUND | __WQ_ORDERED | (flags),\
581 1, lockdep_map, ##args))
582 #endif
583
584 /**
585 * alloc_ordered_workqueue - allocate an ordered workqueue
586 * @fmt: printf format for the name of the workqueue
587 * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
588 * @args: args for @fmt
589 *
590 * Allocate an ordered workqueue. An ordered workqueue executes at
591 * most one work item at any given time in the queued order. They are
592 * implemented as unbound workqueues with @max_active of one.
593 *
594 * RETURNS:
595 * Pointer to the allocated workqueue on success, %NULL on failure.
596 */
597 #define alloc_ordered_workqueue(fmt, flags, args...) \
598 alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | (flags), 1, ##args)
599 #define devm_alloc_ordered_workqueue(dev, fmt, flags, args...) \
600 devm_alloc_workqueue(dev, fmt, WQ_UNBOUND | __WQ_ORDERED | (flags), 1, ##args)
601
602 #define create_workqueue(name) \
603 alloc_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM | WQ_PERCPU, 1, (name))
604 #define create_freezable_workqueue(name) \
605 alloc_workqueue("%s", __WQ_LEGACY | WQ_FREEZABLE | WQ_UNBOUND | \
606 WQ_MEM_RECLAIM, 1, (name))
607 #define create_singlethread_workqueue(name) \
608 alloc_ordered_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, name)
609
610 #define from_work(var, callback_work, work_fieldname) \
611 container_of(callback_work, typeof(*var), work_fieldname)
612
613 extern void destroy_workqueue(struct workqueue_struct *wq);
614
615 struct workqueue_attrs *alloc_workqueue_attrs_noprof(void);
616 #define alloc_workqueue_attrs(...) alloc_hooks(alloc_workqueue_attrs_noprof(__VA_ARGS__))
617
618 void free_workqueue_attrs(struct workqueue_attrs *attrs);
619 int apply_workqueue_attrs(struct workqueue_struct *wq,
620 const struct workqueue_attrs *attrs);
621 extern int workqueue_unbound_housekeeping_update(const struct cpumask *hk);
622
623 extern bool queue_work_on(int cpu, struct workqueue_struct *wq,
624 struct work_struct *work);
625 extern bool queue_work_node(int node, struct workqueue_struct *wq,
626 struct work_struct *work);
627 extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
628 struct delayed_work *work, unsigned long delay);
629 extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
630 struct delayed_work *dwork, unsigned long delay);
631 extern bool queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork);
632
633 extern void __flush_workqueue(struct workqueue_struct *wq);
634 extern void drain_workqueue(struct workqueue_struct *wq);
635
636 extern int schedule_on_each_cpu(work_func_t func);
637
638 int execute_in_process_context(work_func_t fn, struct execute_work *);
639
640 extern bool flush_work(struct work_struct *work);
641 extern bool cancel_work(struct work_struct *work);
642 extern bool cancel_work_sync(struct work_struct *work);
643
644 extern bool flush_delayed_work(struct delayed_work *dwork);
645 extern bool cancel_delayed_work(struct delayed_work *dwork);
646 extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
647
648 extern bool disable_work(struct work_struct *work);
649 extern bool disable_work_sync(struct work_struct *work);
650 extern bool enable_work(struct work_struct *work);
651
652 extern bool disable_delayed_work(struct delayed_work *dwork);
653 extern bool disable_delayed_work_sync(struct delayed_work *dwork);
654 extern bool enable_delayed_work(struct delayed_work *dwork);
655
656 extern bool flush_rcu_work(struct rcu_work *rwork);
657
658 extern void workqueue_set_max_active(struct workqueue_struct *wq,
659 int max_active);
660 extern void workqueue_set_min_active(struct workqueue_struct *wq,
661 int min_active);
662 extern struct work_struct *current_work(void);
663 extern bool current_is_workqueue_rescuer(void);
664 extern bool current_is_workqueue_mem_reclaim(void);
665 extern bool workqueue_congested(int cpu, struct workqueue_struct *wq);
666 extern unsigned int work_busy(struct work_struct *work);
667 extern __printf(1, 2) void set_worker_desc(const char *fmt, ...);
668 extern void print_worker_info(const char *log_lvl, struct task_struct *task);
669 extern void show_all_workqueues(void);
670 extern void show_freezable_workqueues(void);
671 extern void show_one_workqueue(struct workqueue_struct *wq);
672 extern void wq_worker_comm(char *buf, size_t size, struct task_struct *task);
673
674 /**
675 * queue_work - queue work on a workqueue
676 * @wq: workqueue to use
677 * @work: work to queue
678 *
679 * Returns %false if @work was already on a queue, %true otherwise.
680 *
681 * We queue the work to the CPU on which it was submitted, but if the CPU dies
682 * it can be processed by another CPU.
683 *
684 * Memory-ordering properties: If it returns %true, guarantees that all stores
685 * preceding the call to queue_work() in the program order will be visible from
686 * the CPU which will execute @work by the time such work executes, e.g.,
687 *
688 * { x is initially 0 }
689 *
690 * CPU0 CPU1
691 *
692 * WRITE_ONCE(x, 1); [ @work is being executed ]
693 * r0 = queue_work(wq, work); r1 = READ_ONCE(x);
694 *
695 * Forbids: r0 == true && r1 == 0
696 */
queue_work(struct workqueue_struct * wq,struct work_struct * work)697 static inline bool queue_work(struct workqueue_struct *wq,
698 struct work_struct *work)
699 {
700 return queue_work_on(WORK_CPU_UNBOUND, wq, work);
701 }
702
703 /**
704 * queue_delayed_work - queue work on a workqueue after delay
705 * @wq: workqueue to use
706 * @dwork: delayable work to queue
707 * @delay: number of jiffies to wait before queueing
708 *
709 * Equivalent to queue_delayed_work_on() but tries to use the local CPU.
710 */
queue_delayed_work(struct workqueue_struct * wq,struct delayed_work * dwork,unsigned long delay)711 static inline bool queue_delayed_work(struct workqueue_struct *wq,
712 struct delayed_work *dwork,
713 unsigned long delay)
714 {
715 return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
716 }
717
718 /**
719 * mod_delayed_work - modify delay of or queue a delayed work
720 * @wq: workqueue to use
721 * @dwork: work to queue
722 * @delay: number of jiffies to wait before queueing
723 *
724 * mod_delayed_work_on() on local CPU.
725 */
mod_delayed_work(struct workqueue_struct * wq,struct delayed_work * dwork,unsigned long delay)726 static inline bool mod_delayed_work(struct workqueue_struct *wq,
727 struct delayed_work *dwork,
728 unsigned long delay)
729 {
730 return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
731 }
732
733 /**
734 * schedule_work_on - put work task on a specific cpu
735 * @cpu: cpu to put the work task on
736 * @work: job to be done
737 *
738 * This puts a job on a specific cpu
739 */
schedule_work_on(int cpu,struct work_struct * work)740 static inline bool schedule_work_on(int cpu, struct work_struct *work)
741 {
742 return queue_work_on(cpu, system_percpu_wq, work);
743 }
744
745 /**
746 * schedule_work - put work task in per-CPU workqueue
747 * @work: job to be done
748 *
749 * Returns %false if @work was already on the system per-CPU workqueue and
750 * %true otherwise.
751 *
752 * This puts a job in the system per-CPU workqueue if it was not already
753 * queued and leaves it in the same position on the system per-CPU
754 * workqueue otherwise.
755 *
756 * Shares the same memory-ordering properties of queue_work(), cf. the
757 * DocBook header of queue_work().
758 */
schedule_work(struct work_struct * work)759 static inline bool schedule_work(struct work_struct *work)
760 {
761 return queue_work(system_percpu_wq, work);
762 }
763
764 /**
765 * enable_and_queue_work - Enable and queue a work item on a specific workqueue
766 * @wq: The target workqueue
767 * @work: The work item to be enabled and queued
768 *
769 * This function combines the operations of enable_work() and queue_work(),
770 * providing a convenient way to enable and queue a work item in a single call.
771 * It invokes enable_work() on @work and then queues it if the disable depth
772 * reached 0. Returns %true if the disable depth reached 0 and @work is queued,
773 * and %false otherwise.
774 *
775 * Note that @work is always queued when disable depth reaches zero. If the
776 * desired behavior is queueing only if certain events took place while @work is
777 * disabled, the user should implement the necessary state tracking and perform
778 * explicit conditional queueing after enable_work().
779 */
enable_and_queue_work(struct workqueue_struct * wq,struct work_struct * work)780 static inline bool enable_and_queue_work(struct workqueue_struct *wq,
781 struct work_struct *work)
782 {
783 if (enable_work(work)) {
784 queue_work(wq, work);
785 return true;
786 }
787 return false;
788 }
789
790 /*
791 * Detect attempt to flush system-wide workqueues at compile time when possible.
792 * Warn attempt to flush system-wide workqueues at runtime.
793 *
794 * See https://lkml.kernel.org/r/49925af7-78a8-a3dd-bce6-cfc02e1a9236@I-love.SAKURA.ne.jp
795 * for reasons and steps for converting system-wide workqueues into local workqueues.
796 */
797 extern void __warn_flushing_systemwide_wq(void)
798 __compiletime_warning("Please avoid flushing system-wide workqueues.");
799
800 /* Please stop using this function, for this function will be removed in near future. */
801 #define flush_scheduled_work() \
802 ({ \
803 __warn_flushing_systemwide_wq(); \
804 __flush_workqueue(system_percpu_wq); \
805 })
806
807 #define flush_workqueue(wq) \
808 ({ \
809 struct workqueue_struct *_wq = (wq); \
810 \
811 if ((__builtin_constant_p(_wq == system_percpu_wq) && \
812 _wq == system_percpu_wq) || \
813 (__builtin_constant_p(_wq == system_highpri_wq) && \
814 _wq == system_highpri_wq) || \
815 (__builtin_constant_p(_wq == system_long_wq) && \
816 _wq == system_long_wq) || \
817 (__builtin_constant_p(_wq == system_dfl_long_wq) && \
818 _wq == system_dfl_long_wq) || \
819 (__builtin_constant_p(_wq == system_dfl_wq) && \
820 _wq == system_dfl_wq) || \
821 (__builtin_constant_p(_wq == system_freezable_wq) && \
822 _wq == system_freezable_wq) || \
823 (__builtin_constant_p(_wq == system_power_efficient_wq) && \
824 _wq == system_power_efficient_wq) || \
825 (__builtin_constant_p(_wq == system_freezable_power_efficient_wq) && \
826 _wq == system_freezable_power_efficient_wq)) \
827 __warn_flushing_systemwide_wq(); \
828 __flush_workqueue(_wq); \
829 })
830
831 /**
832 * schedule_delayed_work_on - queue work in per-CPU workqueue on CPU after delay
833 * @cpu: cpu to use
834 * @dwork: job to be done
835 * @delay: number of jiffies to wait
836 *
837 * After waiting for a given time this puts a job in the system per-CPU
838 * workqueue on the specified CPU.
839 */
schedule_delayed_work_on(int cpu,struct delayed_work * dwork,unsigned long delay)840 static inline bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork,
841 unsigned long delay)
842 {
843 return queue_delayed_work_on(cpu, system_percpu_wq, dwork, delay);
844 }
845
846 /**
847 * schedule_delayed_work - put work task in per-CPU workqueue after delay
848 * @dwork: job to be done
849 * @delay: number of jiffies to wait or 0 for immediate execution
850 *
851 * After waiting for a given time this puts a job in the system per-CPU
852 * workqueue.
853 */
schedule_delayed_work(struct delayed_work * dwork,unsigned long delay)854 static inline bool schedule_delayed_work(struct delayed_work *dwork,
855 unsigned long delay)
856 {
857 return queue_delayed_work(system_percpu_wq, dwork, delay);
858 }
859
860 #ifndef CONFIG_SMP
work_on_cpu(int cpu,long (* fn)(void *),void * arg)861 static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
862 {
863 return fn(arg);
864 }
work_on_cpu_safe(int cpu,long (* fn)(void *),void * arg)865 static inline long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg)
866 {
867 return fn(arg);
868 }
869 #else
870 long work_on_cpu_key(int cpu, long (*fn)(void *),
871 void *arg, struct lock_class_key *key);
872 /*
873 * A new key is defined for each caller to make sure the work
874 * associated with the function doesn't share its locking class.
875 */
876 #define work_on_cpu(_cpu, _fn, _arg) \
877 ({ \
878 static struct lock_class_key __key; \
879 \
880 work_on_cpu_key(_cpu, _fn, _arg, &__key); \
881 })
882
883 #endif /* CONFIG_SMP */
884
885 #ifdef CONFIG_FREEZER
886 extern void freeze_workqueues_begin(void);
887 extern bool freeze_workqueues_busy(void);
888 extern void thaw_workqueues(void);
889 #endif /* CONFIG_FREEZER */
890
891 #ifdef CONFIG_SYSFS
892 int workqueue_sysfs_register(struct workqueue_struct *wq);
893 #else /* CONFIG_SYSFS */
workqueue_sysfs_register(struct workqueue_struct * wq)894 static inline int workqueue_sysfs_register(struct workqueue_struct *wq)
895 { return 0; }
896 #endif /* CONFIG_SYSFS */
897
898 #ifdef CONFIG_WQ_WATCHDOG
899 void wq_watchdog_touch(int cpu);
900 #else /* CONFIG_WQ_WATCHDOG */
wq_watchdog_touch(int cpu)901 static inline void wq_watchdog_touch(int cpu) { }
902 #endif /* CONFIG_WQ_WATCHDOG */
903
904 #ifdef CONFIG_SMP
905 int workqueue_prepare_cpu(unsigned int cpu);
906 int workqueue_online_cpu(unsigned int cpu);
907 int workqueue_offline_cpu(unsigned int cpu);
908 #endif
909
910 void __init workqueue_init_early(void);
911 void __init workqueue_init(void);
912 void __init workqueue_init_topology(void);
913
914 #endif
915