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 :
72 : /*
73 : * When a work item is off queue, its high bits point to the last
74 : * pool it was on. Cap at 31 bits and use the highest number to
75 : * indicate that no pool is associated.
76 : */
77 : WORK_OFFQ_FLAG_BITS = 1,
78 : WORK_OFFQ_POOL_SHIFT = WORK_OFFQ_FLAG_BASE + WORK_OFFQ_FLAG_BITS,
79 : WORK_OFFQ_LEFT = BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT,
80 : WORK_OFFQ_POOL_BITS = WORK_OFFQ_LEFT <= 31 ? WORK_OFFQ_LEFT : 31,
81 :
82 : /* bit mask for work_busy() return values */
83 : WORK_BUSY_PENDING = 1 << 0,
84 : WORK_BUSY_RUNNING = 1 << 1,
85 :
86 : /* maximum string length for set_worker_desc() */
87 : WORKER_DESC_LEN = 24,
88 : };
89 :
90 : /* Convenience constants - of type 'unsigned long', not 'enum'! */
91 : #define WORK_OFFQ_CANCELING (1ul << __WORK_OFFQ_CANCELING)
92 : #define WORK_OFFQ_POOL_NONE ((1ul << WORK_OFFQ_POOL_BITS) - 1)
93 : #define WORK_STRUCT_NO_POOL (WORK_OFFQ_POOL_NONE << WORK_OFFQ_POOL_SHIFT)
94 :
95 : #define WORK_STRUCT_FLAG_MASK ((1ul << WORK_STRUCT_FLAG_BITS) - 1)
96 : #define WORK_STRUCT_WQ_DATA_MASK (~WORK_STRUCT_FLAG_MASK)
97 :
98 : struct work_struct {
99 : atomic_long_t data;
100 : struct list_head entry;
101 : work_func_t func;
102 : #ifdef CONFIG_LOCKDEP
103 : struct lockdep_map lockdep_map;
104 : #endif
105 : };
106 :
107 : #define WORK_DATA_INIT() ATOMIC_LONG_INIT((unsigned long)WORK_STRUCT_NO_POOL)
108 : #define WORK_DATA_STATIC_INIT() \
109 : ATOMIC_LONG_INIT((unsigned long)(WORK_STRUCT_NO_POOL | WORK_STRUCT_STATIC))
110 :
111 : struct delayed_work {
112 : struct work_struct work;
113 : struct timer_list timer;
114 :
115 : /* target workqueue and CPU ->timer uses to queue ->work */
116 : struct workqueue_struct *wq;
117 : int cpu;
118 : };
119 :
120 : struct rcu_work {
121 : struct work_struct work;
122 : struct rcu_head rcu;
123 :
124 : /* target workqueue ->rcu uses to queue ->work */
125 : struct workqueue_struct *wq;
126 : };
127 :
128 : /**
129 : * struct workqueue_attrs - A struct for workqueue attributes.
130 : *
131 : * This can be used to change attributes of an unbound workqueue.
132 : */
133 : struct workqueue_attrs {
134 : /**
135 : * @nice: nice level
136 : */
137 : int nice;
138 :
139 : /**
140 : * @cpumask: allowed CPUs
141 : */
142 : cpumask_var_t cpumask;
143 :
144 : /**
145 : * @no_numa: disable NUMA affinity
146 : *
147 : * Unlike other fields, ``no_numa`` isn't a property of a worker_pool. It
148 : * only modifies how :c:func:`apply_workqueue_attrs` select pools and thus
149 : * doesn't participate in pool hash calculations or equality comparisons.
150 : */
151 : bool no_numa;
152 : };
153 :
154 : static inline struct delayed_work *to_delayed_work(struct work_struct *work)
155 : {
156 21 : return container_of(work, struct delayed_work, work);
157 : }
158 :
159 : static inline struct rcu_work *to_rcu_work(struct work_struct *work)
160 : {
161 0 : return container_of(work, struct rcu_work, work);
162 : }
163 :
164 : struct execute_work {
165 : struct work_struct work;
166 : };
167 :
168 : #ifdef CONFIG_LOCKDEP
169 : /*
170 : * NB: because we have to copy the lockdep_map, setting _key
171 : * here is required, otherwise it could get initialised to the
172 : * copy of the lockdep_map!
173 : */
174 : #define __WORK_INIT_LOCKDEP_MAP(n, k) \
175 : .lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k),
176 : #else
177 : #define __WORK_INIT_LOCKDEP_MAP(n, k)
178 : #endif
179 :
180 : #define __WORK_INITIALIZER(n, f) { \
181 : .data = WORK_DATA_STATIC_INIT(), \
182 : .entry = { &(n).entry, &(n).entry }, \
183 : .func = (f), \
184 : __WORK_INIT_LOCKDEP_MAP(#n, &(n)) \
185 : }
186 :
187 : #define __DELAYED_WORK_INITIALIZER(n, f, tflags) { \
188 : .work = __WORK_INITIALIZER((n).work, (f)), \
189 : .timer = __TIMER_INITIALIZER(delayed_work_timer_fn,\
190 : (tflags) | TIMER_IRQSAFE), \
191 : }
192 :
193 : #define DECLARE_WORK(n, f) \
194 : struct work_struct n = __WORK_INITIALIZER(n, f)
195 :
196 : #define DECLARE_DELAYED_WORK(n, f) \
197 : struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, 0)
198 :
199 : #define DECLARE_DEFERRABLE_WORK(n, f) \
200 : struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, TIMER_DEFERRABLE)
201 :
202 : #ifdef CONFIG_DEBUG_OBJECTS_WORK
203 : extern void __init_work(struct work_struct *work, int onstack);
204 : extern void destroy_work_on_stack(struct work_struct *work);
205 : extern void destroy_delayed_work_on_stack(struct delayed_work *work);
206 : static inline unsigned int work_static(struct work_struct *work)
207 : {
208 : return *work_data_bits(work) & WORK_STRUCT_STATIC;
209 : }
210 : #else
211 : static inline void __init_work(struct work_struct *work, int onstack) { }
212 : static inline void destroy_work_on_stack(struct work_struct *work) { }
213 : static inline void destroy_delayed_work_on_stack(struct delayed_work *work) { }
214 : static inline unsigned int work_static(struct work_struct *work) { return 0; }
215 : #endif
216 :
217 : /*
218 : * initialize all of a work item in one go
219 : *
220 : * NOTE! No point in using "atomic_long_set()": using a direct
221 : * assignment of the work data initializer allows the compiler
222 : * to generate better code.
223 : */
224 : #ifdef CONFIG_LOCKDEP
225 : #define __INIT_WORK(_work, _func, _onstack) \
226 : do { \
227 : static struct lock_class_key __key; \
228 : \
229 : __init_work((_work), _onstack); \
230 : (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
231 : lockdep_init_map(&(_work)->lockdep_map, "(work_completion)"#_work, &__key, 0); \
232 : INIT_LIST_HEAD(&(_work)->entry); \
233 : (_work)->func = (_func); \
234 : } while (0)
235 : #else
236 : #define __INIT_WORK(_work, _func, _onstack) \
237 : do { \
238 : __init_work((_work), _onstack); \
239 : (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
240 : INIT_LIST_HEAD(&(_work)->entry); \
241 : (_work)->func = (_func); \
242 : } while (0)
243 : #endif
244 :
245 : #define INIT_WORK(_work, _func) \
246 : __INIT_WORK((_work), (_func), 0)
247 :
248 : #define INIT_WORK_ONSTACK(_work, _func) \
249 : __INIT_WORK((_work), (_func), 1)
250 :
251 : #define __INIT_DELAYED_WORK(_work, _func, _tflags) \
252 : do { \
253 : INIT_WORK(&(_work)->work, (_func)); \
254 : __init_timer(&(_work)->timer, \
255 : delayed_work_timer_fn, \
256 : (_tflags) | TIMER_IRQSAFE); \
257 : } while (0)
258 :
259 : #define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags) \
260 : do { \
261 : INIT_WORK_ONSTACK(&(_work)->work, (_func)); \
262 : __init_timer_on_stack(&(_work)->timer, \
263 : delayed_work_timer_fn, \
264 : (_tflags) | TIMER_IRQSAFE); \
265 : } while (0)
266 :
267 : #define INIT_DELAYED_WORK(_work, _func) \
268 : __INIT_DELAYED_WORK(_work, _func, 0)
269 :
270 : #define INIT_DELAYED_WORK_ONSTACK(_work, _func) \
271 : __INIT_DELAYED_WORK_ONSTACK(_work, _func, 0)
272 :
273 : #define INIT_DEFERRABLE_WORK(_work, _func) \
274 : __INIT_DELAYED_WORK(_work, _func, TIMER_DEFERRABLE)
275 :
276 : #define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func) \
277 : __INIT_DELAYED_WORK_ONSTACK(_work, _func, TIMER_DEFERRABLE)
278 :
279 : #define INIT_RCU_WORK(_work, _func) \
280 : INIT_WORK(&(_work)->work, (_func))
281 :
282 : #define INIT_RCU_WORK_ONSTACK(_work, _func) \
283 : INIT_WORK_ONSTACK(&(_work)->work, (_func))
284 :
285 : /**
286 : * work_pending - Find out whether a work item is currently pending
287 : * @work: The work item in question
288 : */
289 : #define work_pending(work) \
290 : test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
291 :
292 : /**
293 : * delayed_work_pending - Find out whether a delayable work item is currently
294 : * pending
295 : * @w: The work item in question
296 : */
297 : #define delayed_work_pending(w) \
298 : work_pending(&(w)->work)
299 :
300 : /*
301 : * Workqueue flags and constants. For details, please refer to
302 : * Documentation/core-api/workqueue.rst.
303 : */
304 : enum {
305 : WQ_UNBOUND = 1 << 1, /* not bound to any cpu */
306 : WQ_FREEZABLE = 1 << 2, /* freeze during suspend */
307 : WQ_MEM_RECLAIM = 1 << 3, /* may be used for memory reclaim */
308 : WQ_HIGHPRI = 1 << 4, /* high priority */
309 : WQ_CPU_INTENSIVE = 1 << 5, /* cpu intensive workqueue */
310 : WQ_SYSFS = 1 << 6, /* visible in sysfs, see workqueue_sysfs_register() */
311 :
312 : /*
313 : * Per-cpu workqueues are generally preferred because they tend to
314 : * show better performance thanks to cache locality. Per-cpu
315 : * workqueues exclude the scheduler from choosing the CPU to
316 : * execute the worker threads, which has an unfortunate side effect
317 : * of increasing power consumption.
318 : *
319 : * The scheduler considers a CPU idle if it doesn't have any task
320 : * to execute and tries to keep idle cores idle to conserve power;
321 : * however, for example, a per-cpu work item scheduled from an
322 : * interrupt handler on an idle CPU will force the scheduler to
323 : * execute the work item on that CPU breaking the idleness, which in
324 : * turn may lead to more scheduling choices which are sub-optimal
325 : * in terms of power consumption.
326 : *
327 : * Workqueues marked with WQ_POWER_EFFICIENT are per-cpu by default
328 : * but become unbound if workqueue.power_efficient kernel param is
329 : * specified. Per-cpu workqueues which are identified to
330 : * contribute significantly to power-consumption are identified and
331 : * marked with this flag and enabling the power_efficient mode
332 : * leads to noticeable power saving at the cost of small
333 : * performance disadvantage.
334 : *
335 : * http://thread.gmane.org/gmane.linux.kernel/1480396
336 : */
337 : WQ_POWER_EFFICIENT = 1 << 7,
338 :
339 : __WQ_DESTROYING = 1 << 15, /* internal: workqueue is destroying */
340 : __WQ_DRAINING = 1 << 16, /* internal: workqueue is draining */
341 : __WQ_ORDERED = 1 << 17, /* internal: workqueue is ordered */
342 : __WQ_LEGACY = 1 << 18, /* internal: create*_workqueue() */
343 : __WQ_ORDERED_EXPLICIT = 1 << 19, /* internal: alloc_ordered_workqueue() */
344 :
345 : WQ_MAX_ACTIVE = 512, /* I like 512, better ideas? */
346 : WQ_MAX_UNBOUND_PER_CPU = 4, /* 4 * #cpus for unbound wq */
347 : WQ_DFL_ACTIVE = WQ_MAX_ACTIVE / 2,
348 : };
349 :
350 : /* unbound wq's aren't per-cpu, scale max_active according to #cpus */
351 : #define WQ_UNBOUND_MAX_ACTIVE \
352 : max_t(int, WQ_MAX_ACTIVE, num_possible_cpus() * WQ_MAX_UNBOUND_PER_CPU)
353 :
354 : /*
355 : * System-wide workqueues which are always present.
356 : *
357 : * system_wq is the one used by schedule[_delayed]_work[_on]().
358 : * Multi-CPU multi-threaded. There are users which expect relatively
359 : * short queue flush time. Don't queue works which can run for too
360 : * long.
361 : *
362 : * system_highpri_wq is similar to system_wq but for work items which
363 : * require WQ_HIGHPRI.
364 : *
365 : * system_long_wq is similar to system_wq but may host long running
366 : * works. Queue flushing might take relatively long.
367 : *
368 : * system_unbound_wq is unbound workqueue. Workers are not bound to
369 : * any specific CPU, not concurrency managed, and all queued works are
370 : * executed immediately as long as max_active limit is not reached and
371 : * resources are available.
372 : *
373 : * system_freezable_wq is equivalent to system_wq except that it's
374 : * freezable.
375 : *
376 : * *_power_efficient_wq are inclined towards saving power and converted
377 : * into WQ_UNBOUND variants if 'wq_power_efficient' is enabled; otherwise,
378 : * they are same as their non-power-efficient counterparts - e.g.
379 : * system_power_efficient_wq is identical to system_wq if
380 : * 'wq_power_efficient' is disabled. See WQ_POWER_EFFICIENT for more info.
381 : */
382 : extern struct workqueue_struct *system_wq;
383 : extern struct workqueue_struct *system_highpri_wq;
384 : extern struct workqueue_struct *system_long_wq;
385 : extern struct workqueue_struct *system_unbound_wq;
386 : extern struct workqueue_struct *system_freezable_wq;
387 : extern struct workqueue_struct *system_power_efficient_wq;
388 : extern struct workqueue_struct *system_freezable_power_efficient_wq;
389 :
390 : /**
391 : * alloc_workqueue - allocate a workqueue
392 : * @fmt: printf format for the name of the workqueue
393 : * @flags: WQ_* flags
394 : * @max_active: max in-flight work items, 0 for default
395 : * remaining args: args for @fmt
396 : *
397 : * Allocate a workqueue with the specified parameters. For detailed
398 : * information on WQ_* flags, please refer to
399 : * Documentation/core-api/workqueue.rst.
400 : *
401 : * RETURNS:
402 : * Pointer to the allocated workqueue on success, %NULL on failure.
403 : */
404 : __printf(1, 4) struct workqueue_struct *
405 : alloc_workqueue(const char *fmt, unsigned int flags, int max_active, ...);
406 :
407 : /**
408 : * alloc_ordered_workqueue - allocate an ordered workqueue
409 : * @fmt: printf format for the name of the workqueue
410 : * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
411 : * @args: args for @fmt
412 : *
413 : * Allocate an ordered workqueue. An ordered workqueue executes at
414 : * most one work item at any given time in the queued order. They are
415 : * implemented as unbound workqueues with @max_active of one.
416 : *
417 : * RETURNS:
418 : * Pointer to the allocated workqueue on success, %NULL on failure.
419 : */
420 : #define alloc_ordered_workqueue(fmt, flags, args...) \
421 : alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | \
422 : __WQ_ORDERED_EXPLICIT | (flags), 1, ##args)
423 :
424 : #define create_workqueue(name) \
425 : alloc_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, 1, (name))
426 : #define create_freezable_workqueue(name) \
427 : alloc_workqueue("%s", __WQ_LEGACY | WQ_FREEZABLE | WQ_UNBOUND | \
428 : WQ_MEM_RECLAIM, 1, (name))
429 : #define create_singlethread_workqueue(name) \
430 : alloc_ordered_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, name)
431 :
432 : extern void destroy_workqueue(struct workqueue_struct *wq);
433 :
434 : struct workqueue_attrs *alloc_workqueue_attrs(void);
435 : void free_workqueue_attrs(struct workqueue_attrs *attrs);
436 : int apply_workqueue_attrs(struct workqueue_struct *wq,
437 : const struct workqueue_attrs *attrs);
438 : int workqueue_set_unbound_cpumask(cpumask_var_t cpumask);
439 :
440 : extern bool queue_work_on(int cpu, struct workqueue_struct *wq,
441 : struct work_struct *work);
442 : extern bool queue_work_node(int node, struct workqueue_struct *wq,
443 : struct work_struct *work);
444 : extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
445 : struct delayed_work *work, unsigned long delay);
446 : extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
447 : struct delayed_work *dwork, unsigned long delay);
448 : extern bool queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork);
449 :
450 : extern void __flush_workqueue(struct workqueue_struct *wq);
451 : extern void drain_workqueue(struct workqueue_struct *wq);
452 :
453 : extern int schedule_on_each_cpu(work_func_t func);
454 :
455 : int execute_in_process_context(work_func_t fn, struct execute_work *);
456 :
457 : extern bool flush_work(struct work_struct *work);
458 : extern bool cancel_work(struct work_struct *work);
459 : extern bool cancel_work_sync(struct work_struct *work);
460 :
461 : extern bool flush_delayed_work(struct delayed_work *dwork);
462 : extern bool cancel_delayed_work(struct delayed_work *dwork);
463 : extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
464 :
465 : extern bool flush_rcu_work(struct rcu_work *rwork);
466 :
467 : extern void workqueue_set_max_active(struct workqueue_struct *wq,
468 : int max_active);
469 : extern struct work_struct *current_work(void);
470 : extern bool current_is_workqueue_rescuer(void);
471 : extern bool workqueue_congested(int cpu, struct workqueue_struct *wq);
472 : extern unsigned int work_busy(struct work_struct *work);
473 : extern __printf(1, 2) void set_worker_desc(const char *fmt, ...);
474 : extern void print_worker_info(const char *log_lvl, struct task_struct *task);
475 : extern void show_all_workqueues(void);
476 : extern void show_freezable_workqueues(void);
477 : extern void show_one_workqueue(struct workqueue_struct *wq);
478 : extern void wq_worker_comm(char *buf, size_t size, struct task_struct *task);
479 :
480 : /**
481 : * queue_work - queue work on a workqueue
482 : * @wq: workqueue to use
483 : * @work: work to queue
484 : *
485 : * Returns %false if @work was already on a queue, %true otherwise.
486 : *
487 : * We queue the work to the CPU on which it was submitted, but if the CPU dies
488 : * it can be processed by another CPU.
489 : *
490 : * Memory-ordering properties: If it returns %true, guarantees that all stores
491 : * preceding the call to queue_work() in the program order will be visible from
492 : * the CPU which will execute @work by the time such work executes, e.g.,
493 : *
494 : * { x is initially 0 }
495 : *
496 : * CPU0 CPU1
497 : *
498 : * WRITE_ONCE(x, 1); [ @work is being executed ]
499 : * r0 = queue_work(wq, work); r1 = READ_ONCE(x);
500 : *
501 : * Forbids: r0 == true && r1 == 0
502 : */
503 : static inline bool queue_work(struct workqueue_struct *wq,
504 : struct work_struct *work)
505 : {
506 15 : return queue_work_on(WORK_CPU_UNBOUND, wq, work);
507 : }
508 :
509 : /**
510 : * queue_delayed_work - queue work on a workqueue after delay
511 : * @wq: workqueue to use
512 : * @dwork: delayable work to queue
513 : * @delay: number of jiffies to wait before queueing
514 : *
515 : * Equivalent to queue_delayed_work_on() but tries to use the local CPU.
516 : */
517 : static inline bool queue_delayed_work(struct workqueue_struct *wq,
518 : struct delayed_work *dwork,
519 : unsigned long delay)
520 : {
521 2 : return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
522 : }
523 :
524 : /**
525 : * mod_delayed_work - modify delay of or queue a delayed work
526 : * @wq: workqueue to use
527 : * @dwork: work to queue
528 : * @delay: number of jiffies to wait before queueing
529 : *
530 : * mod_delayed_work_on() on local CPU.
531 : */
532 : static inline bool mod_delayed_work(struct workqueue_struct *wq,
533 : struct delayed_work *dwork,
534 : unsigned long delay)
535 : {
536 0 : return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
537 : }
538 :
539 : /**
540 : * schedule_work_on - put work task on a specific cpu
541 : * @cpu: cpu to put the work task on
542 : * @work: job to be done
543 : *
544 : * This puts a job on a specific cpu
545 : */
546 : static inline bool schedule_work_on(int cpu, struct work_struct *work)
547 : {
548 0 : return queue_work_on(cpu, system_wq, work);
549 : }
550 :
551 : /**
552 : * schedule_work - put work task in global workqueue
553 : * @work: job to be done
554 : *
555 : * Returns %false if @work was already on the kernel-global workqueue and
556 : * %true otherwise.
557 : *
558 : * This puts a job in the kernel-global workqueue if it was not already
559 : * queued and leaves it in the same position on the kernel-global
560 : * workqueue otherwise.
561 : *
562 : * Shares the same memory-ordering properties of queue_work(), cf. the
563 : * DocBook header of queue_work().
564 : */
565 : static inline bool schedule_work(struct work_struct *work)
566 : {
567 12 : return queue_work(system_wq, work);
568 : }
569 :
570 : /*
571 : * Detect attempt to flush system-wide workqueues at compile time when possible.
572 : *
573 : * See https://lkml.kernel.org/r/49925af7-78a8-a3dd-bce6-cfc02e1a9236@I-love.SAKURA.ne.jp
574 : * for reasons and steps for converting system-wide workqueues into local workqueues.
575 : */
576 : extern void __warn_flushing_systemwide_wq(void)
577 : __compiletime_warning("Please avoid flushing system-wide workqueues.");
578 :
579 : /**
580 : * flush_scheduled_work - ensure that any scheduled work has run to completion.
581 : *
582 : * Forces execution of the kernel-global workqueue and blocks until its
583 : * completion.
584 : *
585 : * It's very easy to get into trouble if you don't take great care.
586 : * Either of the following situations will lead to deadlock:
587 : *
588 : * One of the work items currently on the workqueue needs to acquire
589 : * a lock held by your code or its caller.
590 : *
591 : * Your code is running in the context of a work routine.
592 : *
593 : * They will be detected by lockdep when they occur, but the first might not
594 : * occur very often. It depends on what work items are on the workqueue and
595 : * what locks they need, which you have no control over.
596 : *
597 : * In most situations flushing the entire workqueue is overkill; you merely
598 : * need to know that a particular work item isn't queued and isn't running.
599 : * In such cases you should use cancel_delayed_work_sync() or
600 : * cancel_work_sync() instead.
601 : *
602 : * Please stop calling this function! A conversion to stop flushing system-wide
603 : * workqueues is in progress. This function will be removed after all in-tree
604 : * users stopped calling this function.
605 : */
606 : /*
607 : * The background of commit 771c035372a036f8 ("deprecate the
608 : * '__deprecated' attribute warnings entirely and for good") is that,
609 : * since Linus builds all modules between every single pull he does,
610 : * the standard kernel build needs to be _clean_ in order to be able to
611 : * notice when new problems happen. Therefore, don't emit warning while
612 : * there are in-tree users.
613 : */
614 : #define flush_scheduled_work() \
615 : ({ \
616 : if (0) \
617 : __warn_flushing_systemwide_wq(); \
618 : __flush_workqueue(system_wq); \
619 : })
620 :
621 : /*
622 : * Although there is no longer in-tree caller, for now just emit warning
623 : * in order to give out-of-tree callers time to update.
624 : */
625 : #define flush_workqueue(wq) \
626 : ({ \
627 : struct workqueue_struct *_wq = (wq); \
628 : \
629 : if ((__builtin_constant_p(_wq == system_wq) && \
630 : _wq == system_wq) || \
631 : (__builtin_constant_p(_wq == system_highpri_wq) && \
632 : _wq == system_highpri_wq) || \
633 : (__builtin_constant_p(_wq == system_long_wq) && \
634 : _wq == system_long_wq) || \
635 : (__builtin_constant_p(_wq == system_unbound_wq) && \
636 : _wq == system_unbound_wq) || \
637 : (__builtin_constant_p(_wq == system_freezable_wq) && \
638 : _wq == system_freezable_wq) || \
639 : (__builtin_constant_p(_wq == system_power_efficient_wq) && \
640 : _wq == system_power_efficient_wq) || \
641 : (__builtin_constant_p(_wq == system_freezable_power_efficient_wq) && \
642 : _wq == system_freezable_power_efficient_wq)) \
643 : __warn_flushing_systemwide_wq(); \
644 : __flush_workqueue(_wq); \
645 : })
646 :
647 : /**
648 : * schedule_delayed_work_on - queue work in global workqueue on CPU after delay
649 : * @cpu: cpu to use
650 : * @dwork: job to be done
651 : * @delay: number of jiffies to wait
652 : *
653 : * After waiting for a given time this puts a job in the kernel-global
654 : * workqueue on the specified CPU.
655 : */
656 : static inline bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork,
657 : unsigned long delay)
658 : {
659 : return queue_delayed_work_on(cpu, system_wq, dwork, delay);
660 : }
661 :
662 : /**
663 : * schedule_delayed_work - put work task in global workqueue after delay
664 : * @dwork: job to be done
665 : * @delay: number of jiffies to wait or 0 for immediate execution
666 : *
667 : * After waiting for a given time this puts a job in the kernel-global
668 : * workqueue.
669 : */
670 : static inline bool schedule_delayed_work(struct delayed_work *dwork,
671 : unsigned long delay)
672 : {
673 2 : return queue_delayed_work(system_wq, dwork, delay);
674 : }
675 :
676 : #ifndef CONFIG_SMP
677 : static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
678 : {
679 : return fn(arg);
680 : }
681 : static inline long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg)
682 : {
683 : return fn(arg);
684 : }
685 : #else
686 : long work_on_cpu(int cpu, long (*fn)(void *), void *arg);
687 : long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg);
688 : #endif /* CONFIG_SMP */
689 :
690 : #ifdef CONFIG_FREEZER
691 : extern void freeze_workqueues_begin(void);
692 : extern bool freeze_workqueues_busy(void);
693 : extern void thaw_workqueues(void);
694 : #endif /* CONFIG_FREEZER */
695 :
696 : #ifdef CONFIG_SYSFS
697 : int workqueue_sysfs_register(struct workqueue_struct *wq);
698 : #else /* CONFIG_SYSFS */
699 : static inline int workqueue_sysfs_register(struct workqueue_struct *wq)
700 : { return 0; }
701 : #endif /* CONFIG_SYSFS */
702 :
703 : #ifdef CONFIG_WQ_WATCHDOG
704 : void wq_watchdog_touch(int cpu);
705 : #else /* CONFIG_WQ_WATCHDOG */
706 : static inline void wq_watchdog_touch(int cpu) { }
707 : #endif /* CONFIG_WQ_WATCHDOG */
708 :
709 : #ifdef CONFIG_SMP
710 : int workqueue_prepare_cpu(unsigned int cpu);
711 : int workqueue_online_cpu(unsigned int cpu);
712 : int workqueue_offline_cpu(unsigned int cpu);
713 : #endif
714 :
715 : void __init workqueue_init_early(void);
716 : void __init workqueue_init(void);
717 :
718 : #endif
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