Line data Source code
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 :
153 : static inline struct delayed_work *to_delayed_work(struct work_struct *work)
154 : {
155 33 : return container_of(work, struct delayed_work, work);
156 : }
157 :
158 : static inline struct rcu_work *to_rcu_work(struct work_struct *work)
159 : {
160 0 : 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);
205 : static inline unsigned int work_static(struct work_struct *work)
206 : {
207 : return *work_data_bits(work) & WORK_STRUCT_STATIC;
208 : }
209 : #else
210 : static inline void __init_work(struct work_struct *work, int onstack) { }
211 : static inline void destroy_work_on_stack(struct work_struct *work) { }
212 : static inline void destroy_delayed_work_on_stack(struct delayed_work *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 : */
501 : static inline bool queue_work(struct workqueue_struct *wq,
502 : struct work_struct *work)
503 : {
504 44 : 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 : */
515 : static inline bool queue_delayed_work(struct workqueue_struct *wq,
516 : struct delayed_work *dwork,
517 : unsigned long delay)
518 : {
519 10 : 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 : */
530 : static inline bool mod_delayed_work(struct workqueue_struct *wq,
531 : struct delayed_work *dwork,
532 : unsigned long delay)
533 : {
534 0 : 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 : */
544 : static inline bool schedule_work_on(int cpu, struct work_struct *work)
545 : {
546 0 : 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 : */
563 : static inline bool schedule_work(struct work_struct *work)
564 : {
565 46 : 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 : */
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 : */
668 : static inline bool schedule_delayed_work(struct delayed_work *dwork,
669 : unsigned long delay)
670 : {
671 2 : return queue_delayed_work(system_wq, dwork, delay);
672 : }
673 :
674 : #ifndef CONFIG_SMP
675 : static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
676 : {
677 : return fn(arg);
678 : }
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 */
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 */
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
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