xref: /linux-6.15/include/linux/workqueue.h (revision 498d319b)
1 /*
2  * workqueue.h --- work queue handling for Linux.
3  */
4 
5 #ifndef _LINUX_WORKQUEUE_H
6 #define _LINUX_WORKQUEUE_H
7 
8 #include <linux/timer.h>
9 #include <linux/linkage.h>
10 #include <linux/bitops.h>
11 #include <linux/lockdep.h>
12 #include <linux/threads.h>
13 #include <linux/atomic.h>
14 #include <linux/cpumask.h>
15 
16 struct workqueue_struct;
17 
18 struct work_struct;
19 typedef void (*work_func_t)(struct work_struct *work);
20 void delayed_work_timer_fn(unsigned long __data);
21 
22 /*
23  * The first word is the work queue pointer and the flags rolled into
24  * one
25  */
26 #define work_data_bits(work) ((unsigned long *)(&(work)->data))
27 
28 enum {
29 	WORK_STRUCT_PENDING_BIT	= 0,	/* work item is pending execution */
30 	WORK_STRUCT_DELAYED_BIT	= 1,	/* work item is delayed */
31 	WORK_STRUCT_PWQ_BIT	= 2,	/* data points to pwq */
32 	WORK_STRUCT_LINKED_BIT	= 3,	/* next work is linked to this one */
33 #ifdef CONFIG_DEBUG_OBJECTS_WORK
34 	WORK_STRUCT_STATIC_BIT	= 4,	/* static initializer (debugobjects) */
35 	WORK_STRUCT_COLOR_SHIFT	= 5,	/* color for workqueue flushing */
36 #else
37 	WORK_STRUCT_COLOR_SHIFT	= 4,	/* color for workqueue flushing */
38 #endif
39 
40 	WORK_STRUCT_COLOR_BITS	= 4,
41 
42 	WORK_STRUCT_PENDING	= 1 << WORK_STRUCT_PENDING_BIT,
43 	WORK_STRUCT_DELAYED	= 1 << WORK_STRUCT_DELAYED_BIT,
44 	WORK_STRUCT_PWQ		= 1 << WORK_STRUCT_PWQ_BIT,
45 	WORK_STRUCT_LINKED	= 1 << WORK_STRUCT_LINKED_BIT,
46 #ifdef CONFIG_DEBUG_OBJECTS_WORK
47 	WORK_STRUCT_STATIC	= 1 << WORK_STRUCT_STATIC_BIT,
48 #else
49 	WORK_STRUCT_STATIC	= 0,
50 #endif
51 
52 	/*
53 	 * The last color is no color used for works which don't
54 	 * participate in workqueue flushing.
55 	 */
56 	WORK_NR_COLORS		= (1 << WORK_STRUCT_COLOR_BITS) - 1,
57 	WORK_NO_COLOR		= WORK_NR_COLORS,
58 
59 	/* special cpu IDs */
60 	WORK_CPU_UNBOUND	= NR_CPUS,
61 	WORK_CPU_END		= NR_CPUS + 1,
62 
63 	/*
64 	 * Reserve 7 bits off of pwq pointer w/ debugobjects turned off.
65 	 * This makes pwqs aligned to 256 bytes and allows 15 workqueue
66 	 * flush colors.
67 	 */
68 	WORK_STRUCT_FLAG_BITS	= WORK_STRUCT_COLOR_SHIFT +
69 				  WORK_STRUCT_COLOR_BITS,
70 
71 	/* data contains off-queue information when !WORK_STRUCT_PWQ */
72 	WORK_OFFQ_FLAG_BASE	= WORK_STRUCT_COLOR_SHIFT,
73 
74 	WORK_OFFQ_CANCELING	= (1 << WORK_OFFQ_FLAG_BASE),
75 
76 	/*
77 	 * When a work item is off queue, its high bits point to the last
78 	 * pool it was on.  Cap at 31 bits and use the highest number to
79 	 * indicate that no pool is associated.
80 	 */
81 	WORK_OFFQ_FLAG_BITS	= 1,
82 	WORK_OFFQ_POOL_SHIFT	= WORK_OFFQ_FLAG_BASE + WORK_OFFQ_FLAG_BITS,
83 	WORK_OFFQ_LEFT		= BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT,
84 	WORK_OFFQ_POOL_BITS	= WORK_OFFQ_LEFT <= 31 ? WORK_OFFQ_LEFT : 31,
85 	WORK_OFFQ_POOL_NONE	= (1LU << WORK_OFFQ_POOL_BITS) - 1,
86 
87 	/* convenience constants */
88 	WORK_STRUCT_FLAG_MASK	= (1UL << WORK_STRUCT_FLAG_BITS) - 1,
89 	WORK_STRUCT_WQ_DATA_MASK = ~WORK_STRUCT_FLAG_MASK,
90 	WORK_STRUCT_NO_POOL	= (unsigned long)WORK_OFFQ_POOL_NONE << WORK_OFFQ_POOL_SHIFT,
91 
92 	/* bit mask for work_busy() return values */
93 	WORK_BUSY_PENDING	= 1 << 0,
94 	WORK_BUSY_RUNNING	= 1 << 1,
95 
96 	/* maximum string length for set_worker_desc() */
97 	WORKER_DESC_LEN		= 24,
98 };
99 
100 struct work_struct {
101 	atomic_long_t data;
102 	struct list_head entry;
103 	work_func_t func;
104 #ifdef CONFIG_LOCKDEP
105 	struct lockdep_map lockdep_map;
106 #endif
107 };
108 
109 #define WORK_DATA_INIT()	ATOMIC_LONG_INIT(WORK_STRUCT_NO_POOL)
110 #define WORK_DATA_STATIC_INIT()	\
111 	ATOMIC_LONG_INIT(WORK_STRUCT_NO_POOL | WORK_STRUCT_STATIC)
112 
113 struct delayed_work {
114 	struct work_struct work;
115 	struct timer_list timer;
116 
117 	/* target workqueue and CPU ->timer uses to queue ->work */
118 	struct workqueue_struct *wq;
119 	int cpu;
120 };
121 
122 /*
123  * A struct for workqueue attributes.  This can be used to change
124  * attributes of an unbound workqueue.
125  *
126  * Unlike other fields, ->no_numa isn't a property of a worker_pool.  It
127  * only modifies how apply_workqueue_attrs() select pools and thus doesn't
128  * participate in pool hash calculations or equality comparisons.
129  */
130 struct workqueue_attrs {
131 	int			nice;		/* nice level */
132 	cpumask_var_t		cpumask;	/* allowed CPUs */
133 	bool			no_numa;	/* disable NUMA affinity */
134 };
135 
136 static inline struct delayed_work *to_delayed_work(struct work_struct *work)
137 {
138 	return container_of(work, struct delayed_work, work);
139 }
140 
141 struct execute_work {
142 	struct work_struct work;
143 };
144 
145 #ifdef CONFIG_LOCKDEP
146 /*
147  * NB: because we have to copy the lockdep_map, setting _key
148  * here is required, otherwise it could get initialised to the
149  * copy of the lockdep_map!
150  */
151 #define __WORK_INIT_LOCKDEP_MAP(n, k) \
152 	.lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k),
153 #else
154 #define __WORK_INIT_LOCKDEP_MAP(n, k)
155 #endif
156 
157 #define __WORK_INITIALIZER(n, f) {					\
158 	.data = WORK_DATA_STATIC_INIT(),				\
159 	.entry	= { &(n).entry, &(n).entry },				\
160 	.func = (f),							\
161 	__WORK_INIT_LOCKDEP_MAP(#n, &(n))				\
162 	}
163 
164 #define __DELAYED_WORK_INITIALIZER(n, f, tflags) {			\
165 	.work = __WORK_INITIALIZER((n).work, (f)),			\
166 	.timer = __TIMER_INITIALIZER(delayed_work_timer_fn,		\
167 				     0, (unsigned long)&(n),		\
168 				     (tflags) | TIMER_IRQSAFE),		\
169 	}
170 
171 #define DECLARE_WORK(n, f)						\
172 	struct work_struct n = __WORK_INITIALIZER(n, f)
173 
174 #define DECLARE_DELAYED_WORK(n, f)					\
175 	struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, 0)
176 
177 #define DECLARE_DEFERRABLE_WORK(n, f)					\
178 	struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, TIMER_DEFERRABLE)
179 
180 /*
181  * initialize a work item's function pointer
182  */
183 #define PREPARE_WORK(_work, _func)					\
184 	do {								\
185 		(_work)->func = (_func);				\
186 	} while (0)
187 
188 #define PREPARE_DELAYED_WORK(_work, _func)				\
189 	PREPARE_WORK(&(_work)->work, (_func))
190 
191 #ifdef CONFIG_DEBUG_OBJECTS_WORK
192 extern void __init_work(struct work_struct *work, int onstack);
193 extern void destroy_work_on_stack(struct work_struct *work);
194 static inline unsigned int work_static(struct work_struct *work)
195 {
196 	return *work_data_bits(work) & WORK_STRUCT_STATIC;
197 }
198 #else
199 static inline void __init_work(struct work_struct *work, int onstack) { }
200 static inline void destroy_work_on_stack(struct work_struct *work) { }
201 static inline unsigned int work_static(struct work_struct *work) { return 0; }
202 #endif
203 
204 /*
205  * initialize all of a work item in one go
206  *
207  * NOTE! No point in using "atomic_long_set()": using a direct
208  * assignment of the work data initializer allows the compiler
209  * to generate better code.
210  */
211 #ifdef CONFIG_LOCKDEP
212 #define __INIT_WORK(_work, _func, _onstack)				\
213 	do {								\
214 		static struct lock_class_key __key;			\
215 									\
216 		__init_work((_work), _onstack);				\
217 		(_work)->data = (atomic_long_t) WORK_DATA_INIT();	\
218 		lockdep_init_map(&(_work)->lockdep_map, #_work, &__key, 0); \
219 		INIT_LIST_HEAD(&(_work)->entry);			\
220 		PREPARE_WORK((_work), (_func));				\
221 	} while (0)
222 #else
223 #define __INIT_WORK(_work, _func, _onstack)				\
224 	do {								\
225 		__init_work((_work), _onstack);				\
226 		(_work)->data = (atomic_long_t) WORK_DATA_INIT();	\
227 		INIT_LIST_HEAD(&(_work)->entry);			\
228 		PREPARE_WORK((_work), (_func));				\
229 	} while (0)
230 #endif
231 
232 #define INIT_WORK(_work, _func)						\
233 	do {								\
234 		__INIT_WORK((_work), (_func), 0);			\
235 	} while (0)
236 
237 #define INIT_WORK_ONSTACK(_work, _func)					\
238 	do {								\
239 		__INIT_WORK((_work), (_func), 1);			\
240 	} while (0)
241 
242 #define __INIT_DELAYED_WORK(_work, _func, _tflags)			\
243 	do {								\
244 		INIT_WORK(&(_work)->work, (_func));			\
245 		__setup_timer(&(_work)->timer, delayed_work_timer_fn,	\
246 			      (unsigned long)(_work),			\
247 			      (_tflags) | TIMER_IRQSAFE);		\
248 	} while (0)
249 
250 #define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags)		\
251 	do {								\
252 		INIT_WORK_ONSTACK(&(_work)->work, (_func));		\
253 		__setup_timer_on_stack(&(_work)->timer,			\
254 				       delayed_work_timer_fn,		\
255 				       (unsigned long)(_work),		\
256 				       (_tflags) | TIMER_IRQSAFE);	\
257 	} while (0)
258 
259 #define INIT_DELAYED_WORK(_work, _func)					\
260 	__INIT_DELAYED_WORK(_work, _func, 0)
261 
262 #define INIT_DELAYED_WORK_ONSTACK(_work, _func)				\
263 	__INIT_DELAYED_WORK_ONSTACK(_work, _func, 0)
264 
265 #define INIT_DEFERRABLE_WORK(_work, _func)				\
266 	__INIT_DELAYED_WORK(_work, _func, TIMER_DEFERRABLE)
267 
268 #define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func)			\
269 	__INIT_DELAYED_WORK_ONSTACK(_work, _func, TIMER_DEFERRABLE)
270 
271 /**
272  * work_pending - Find out whether a work item is currently pending
273  * @work: The work item in question
274  */
275 #define work_pending(work) \
276 	test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
277 
278 /**
279  * delayed_work_pending - Find out whether a delayable work item is currently
280  * pending
281  * @work: The work item in question
282  */
283 #define delayed_work_pending(w) \
284 	work_pending(&(w)->work)
285 
286 /**
287  * work_clear_pending - for internal use only, mark a work item as not pending
288  * @work: The work item in question
289  */
290 #define work_clear_pending(work) \
291 	clear_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
292 
293 /*
294  * Workqueue flags and constants.  For details, please refer to
295  * Documentation/workqueue.txt.
296  */
297 enum {
298 	/*
299 	 * All wqs are now non-reentrant making the following flag
300 	 * meaningless.  Will be removed.
301 	 */
302 	WQ_NON_REENTRANT	= 1 << 0, /* DEPRECATED */
303 
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 instensive workqueue */
309 	WQ_SYSFS		= 1 << 6, /* visible in sysfs, see wq_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 	 * excute 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_DRAINING		= 1 << 16, /* internal: workqueue is draining */
339 	__WQ_ORDERED		= 1 << 17, /* internal: workqueue is ordered */
340 
341 	WQ_MAX_ACTIVE		= 512,	  /* I like 512, better ideas? */
342 	WQ_MAX_UNBOUND_PER_CPU	= 4,	  /* 4 * #cpus for unbound wq */
343 	WQ_DFL_ACTIVE		= WQ_MAX_ACTIVE / 2,
344 };
345 
346 /* unbound wq's aren't per-cpu, scale max_active according to #cpus */
347 #define WQ_UNBOUND_MAX_ACTIVE	\
348 	max_t(int, WQ_MAX_ACTIVE, num_possible_cpus() * WQ_MAX_UNBOUND_PER_CPU)
349 
350 /*
351  * System-wide workqueues which are always present.
352  *
353  * system_wq is the one used by schedule[_delayed]_work[_on]().
354  * Multi-CPU multi-threaded.  There are users which expect relatively
355  * short queue flush time.  Don't queue works which can run for too
356  * long.
357  *
358  * system_long_wq is similar to system_wq but may host long running
359  * works.  Queue flushing might take relatively long.
360  *
361  * system_unbound_wq is unbound workqueue.  Workers are not bound to
362  * any specific CPU, not concurrency managed, and all queued works are
363  * executed immediately as long as max_active limit is not reached and
364  * resources are available.
365  *
366  * system_freezable_wq is equivalent to system_wq except that it's
367  * freezable.
368  *
369  * *_power_efficient_wq are inclined towards saving power and converted
370  * into WQ_UNBOUND variants if 'wq_power_efficient' is enabled; otherwise,
371  * they are same as their non-power-efficient counterparts - e.g.
372  * system_power_efficient_wq is identical to system_wq if
373  * 'wq_power_efficient' is disabled.  See WQ_POWER_EFFICIENT for more info.
374  */
375 extern struct workqueue_struct *system_wq;
376 extern struct workqueue_struct *system_long_wq;
377 extern struct workqueue_struct *system_unbound_wq;
378 extern struct workqueue_struct *system_freezable_wq;
379 extern struct workqueue_struct *system_power_efficient_wq;
380 extern struct workqueue_struct *system_freezable_power_efficient_wq;
381 
382 static inline struct workqueue_struct * __deprecated __system_nrt_wq(void)
383 {
384 	return system_wq;
385 }
386 
387 static inline struct workqueue_struct * __deprecated __system_nrt_freezable_wq(void)
388 {
389 	return system_freezable_wq;
390 }
391 
392 /* equivlalent to system_wq and system_freezable_wq, deprecated */
393 #define system_nrt_wq			__system_nrt_wq()
394 #define system_nrt_freezable_wq		__system_nrt_freezable_wq()
395 
396 extern struct workqueue_struct *
397 __alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active,
398 	struct lock_class_key *key, const char *lock_name, ...) __printf(1, 6);
399 
400 /**
401  * alloc_workqueue - allocate a workqueue
402  * @fmt: printf format for the name of the workqueue
403  * @flags: WQ_* flags
404  * @max_active: max in-flight work items, 0 for default
405  * @args: args for @fmt
406  *
407  * Allocate a workqueue with the specified parameters.  For detailed
408  * information on WQ_* flags, please refer to Documentation/workqueue.txt.
409  *
410  * The __lock_name macro dance is to guarantee that single lock_class_key
411  * doesn't end up with different namesm, which isn't allowed by lockdep.
412  *
413  * RETURNS:
414  * Pointer to the allocated workqueue on success, %NULL on failure.
415  */
416 #ifdef CONFIG_LOCKDEP
417 #define alloc_workqueue(fmt, flags, max_active, args...)		\
418 ({									\
419 	static struct lock_class_key __key;				\
420 	const char *__lock_name;					\
421 									\
422 	if (__builtin_constant_p(fmt))					\
423 		__lock_name = (fmt);					\
424 	else								\
425 		__lock_name = #fmt;					\
426 									\
427 	__alloc_workqueue_key((fmt), (flags), (max_active),		\
428 			      &__key, __lock_name, ##args);		\
429 })
430 #else
431 #define alloc_workqueue(fmt, flags, max_active, args...)		\
432 	__alloc_workqueue_key((fmt), (flags), (max_active),		\
433 			      NULL, NULL, ##args)
434 #endif
435 
436 /**
437  * alloc_ordered_workqueue - allocate an ordered workqueue
438  * @fmt: printf format for the name of the workqueue
439  * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
440  * @args: args for @fmt
441  *
442  * Allocate an ordered workqueue.  An ordered workqueue executes at
443  * most one work item at any given time in the queued order.  They are
444  * implemented as unbound workqueues with @max_active of one.
445  *
446  * RETURNS:
447  * Pointer to the allocated workqueue on success, %NULL on failure.
448  */
449 #define alloc_ordered_workqueue(fmt, flags, args...)			\
450 	alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | (flags), 1, ##args)
451 
452 #define create_workqueue(name)						\
453 	alloc_workqueue("%s", WQ_MEM_RECLAIM, 1, (name))
454 #define create_freezable_workqueue(name)				\
455 	alloc_workqueue("%s", WQ_FREEZABLE | WQ_UNBOUND | WQ_MEM_RECLAIM, \
456 			1, (name))
457 #define create_singlethread_workqueue(name)				\
458 	alloc_workqueue("%s", WQ_UNBOUND | WQ_MEM_RECLAIM, 1, (name))
459 
460 extern void destroy_workqueue(struct workqueue_struct *wq);
461 
462 struct workqueue_attrs *alloc_workqueue_attrs(gfp_t gfp_mask);
463 void free_workqueue_attrs(struct workqueue_attrs *attrs);
464 int apply_workqueue_attrs(struct workqueue_struct *wq,
465 			  const struct workqueue_attrs *attrs);
466 
467 extern bool queue_work_on(int cpu, struct workqueue_struct *wq,
468 			struct work_struct *work);
469 extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
470 			struct delayed_work *work, unsigned long delay);
471 extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
472 			struct delayed_work *dwork, unsigned long delay);
473 
474 extern void flush_workqueue(struct workqueue_struct *wq);
475 extern void drain_workqueue(struct workqueue_struct *wq);
476 extern void flush_scheduled_work(void);
477 
478 extern int schedule_on_each_cpu(work_func_t func);
479 
480 int execute_in_process_context(work_func_t fn, struct execute_work *);
481 
482 extern bool flush_work(struct work_struct *work);
483 extern bool cancel_work_sync(struct work_struct *work);
484 
485 extern bool flush_delayed_work(struct delayed_work *dwork);
486 extern bool cancel_delayed_work(struct delayed_work *dwork);
487 extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
488 
489 extern void workqueue_set_max_active(struct workqueue_struct *wq,
490 				     int max_active);
491 extern bool current_is_workqueue_rescuer(void);
492 extern bool workqueue_congested(int cpu, struct workqueue_struct *wq);
493 extern unsigned int work_busy(struct work_struct *work);
494 extern __printf(1, 2) void set_worker_desc(const char *fmt, ...);
495 extern void print_worker_info(const char *log_lvl, struct task_struct *task);
496 
497 /**
498  * queue_work - queue work on a workqueue
499  * @wq: workqueue to use
500  * @work: work to queue
501  *
502  * Returns %false if @work was already on a queue, %true otherwise.
503  *
504  * We queue the work to the CPU on which it was submitted, but if the CPU dies
505  * it can be processed by another CPU.
506  */
507 static inline bool queue_work(struct workqueue_struct *wq,
508 			      struct work_struct *work)
509 {
510 	return queue_work_on(WORK_CPU_UNBOUND, wq, work);
511 }
512 
513 /**
514  * queue_delayed_work - queue work on a workqueue after delay
515  * @wq: workqueue to use
516  * @dwork: delayable work to queue
517  * @delay: number of jiffies to wait before queueing
518  *
519  * Equivalent to queue_delayed_work_on() but tries to use the local CPU.
520  */
521 static inline bool queue_delayed_work(struct workqueue_struct *wq,
522 				      struct delayed_work *dwork,
523 				      unsigned long delay)
524 {
525 	return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
526 }
527 
528 /**
529  * mod_delayed_work - modify delay of or queue a delayed work
530  * @wq: workqueue to use
531  * @dwork: work to queue
532  * @delay: number of jiffies to wait before queueing
533  *
534  * mod_delayed_work_on() on local CPU.
535  */
536 static inline bool mod_delayed_work(struct workqueue_struct *wq,
537 				    struct delayed_work *dwork,
538 				    unsigned long delay)
539 {
540 	return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
541 }
542 
543 /**
544  * schedule_work_on - put work task on a specific cpu
545  * @cpu: cpu to put the work task on
546  * @work: job to be done
547  *
548  * This puts a job on a specific cpu
549  */
550 static inline bool schedule_work_on(int cpu, struct work_struct *work)
551 {
552 	return queue_work_on(cpu, system_wq, work);
553 }
554 
555 /**
556  * schedule_work - put work task in global workqueue
557  * @work: job to be done
558  *
559  * Returns %false if @work was already on the kernel-global workqueue and
560  * %true otherwise.
561  *
562  * This puts a job in the kernel-global workqueue if it was not already
563  * queued and leaves it in the same position on the kernel-global
564  * workqueue otherwise.
565  */
566 static inline bool schedule_work(struct work_struct *work)
567 {
568 	return queue_work(system_wq, work);
569 }
570 
571 /**
572  * schedule_delayed_work_on - queue work in global workqueue on CPU after delay
573  * @cpu: cpu to use
574  * @dwork: job to be done
575  * @delay: number of jiffies to wait
576  *
577  * After waiting for a given time this puts a job in the kernel-global
578  * workqueue on the specified CPU.
579  */
580 static inline bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork,
581 					    unsigned long delay)
582 {
583 	return queue_delayed_work_on(cpu, system_wq, dwork, delay);
584 }
585 
586 /**
587  * schedule_delayed_work - put work task in global workqueue after delay
588  * @dwork: job to be done
589  * @delay: number of jiffies to wait or 0 for immediate execution
590  *
591  * After waiting for a given time this puts a job in the kernel-global
592  * workqueue.
593  */
594 static inline bool schedule_delayed_work(struct delayed_work *dwork,
595 					 unsigned long delay)
596 {
597 	return queue_delayed_work(system_wq, dwork, delay);
598 }
599 
600 /**
601  * keventd_up - is workqueue initialized yet?
602  */
603 static inline bool keventd_up(void)
604 {
605 	return system_wq != NULL;
606 }
607 
608 /*
609  * Like above, but uses del_timer() instead of del_timer_sync(). This means,
610  * if it returns 0 the timer function may be running and the queueing is in
611  * progress.
612  */
613 static inline bool __deprecated __cancel_delayed_work(struct delayed_work *work)
614 {
615 	bool ret;
616 
617 	ret = del_timer(&work->timer);
618 	if (ret)
619 		work_clear_pending(&work->work);
620 	return ret;
621 }
622 
623 /* used to be different but now identical to flush_work(), deprecated */
624 static inline bool __deprecated flush_work_sync(struct work_struct *work)
625 {
626 	return flush_work(work);
627 }
628 
629 /* used to be different but now identical to flush_delayed_work(), deprecated */
630 static inline bool __deprecated flush_delayed_work_sync(struct delayed_work *dwork)
631 {
632 	return flush_delayed_work(dwork);
633 }
634 
635 #ifndef CONFIG_SMP
636 static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
637 {
638 	return fn(arg);
639 }
640 #else
641 long work_on_cpu(int cpu, long (*fn)(void *), void *arg);
642 #endif /* CONFIG_SMP */
643 
644 #ifdef CONFIG_FREEZER
645 extern void freeze_workqueues_begin(void);
646 extern bool freeze_workqueues_busy(void);
647 extern void thaw_workqueues(void);
648 #endif /* CONFIG_FREEZER */
649 
650 #ifdef CONFIG_SYSFS
651 int workqueue_sysfs_register(struct workqueue_struct *wq);
652 #else	/* CONFIG_SYSFS */
653 static inline int workqueue_sysfs_register(struct workqueue_struct *wq)
654 { return 0; }
655 #endif	/* CONFIG_SYSFS */
656 
657 #endif
658