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
16struct workqueue_struct;
17
18struct work_struct;
19typedef void (*work_func_t)(struct work_struct *work);
20void 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
28enum {
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	/* not bound to any CPU, prefer the local CPU */
60	WORK_CPU_UNBOUND	= NR_CPUS,
61
62	/*
63	 * Reserve 7 bits off of pwq pointer w/ debugobjects turned off.
64	 * This makes pwqs aligned to 256 bytes and allows 15 workqueue
65	 * flush colors.
66	 */
67	WORK_STRUCT_FLAG_BITS	= WORK_STRUCT_COLOR_SHIFT +
68				  WORK_STRUCT_COLOR_BITS,
69
70	/* data contains off-queue information when !WORK_STRUCT_PWQ */
71	WORK_OFFQ_FLAG_BASE	= WORK_STRUCT_COLOR_SHIFT,
72
73	__WORK_OFFQ_CANCELING	= WORK_OFFQ_FLAG_BASE,
74	WORK_OFFQ_CANCELING	= (1 << __WORK_OFFQ_CANCELING),
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
100struct 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
113struct 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 */
130struct workqueue_attrs {
131	int			nice;		/* nice level */
132	cpumask_var_t		cpumask;	/* allowed CPUs */
133	bool			no_numa;	/* disable NUMA affinity */
134};
135
136static inline struct delayed_work *to_delayed_work(struct work_struct *work)
137{
138	return container_of(work, struct delayed_work, work);
139}
140
141struct 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#ifdef CONFIG_DEBUG_OBJECTS_WORK
181extern void __init_work(struct work_struct *work, int onstack);
182extern void destroy_work_on_stack(struct work_struct *work);
183extern void destroy_delayed_work_on_stack(struct delayed_work *work);
184static inline unsigned int work_static(struct work_struct *work)
185{
186	return *work_data_bits(work) & WORK_STRUCT_STATIC;
187}
188#else
189static inline void __init_work(struct work_struct *work, int onstack) { }
190static inline void destroy_work_on_stack(struct work_struct *work) { }
191static inline void destroy_delayed_work_on_stack(struct delayed_work *work) { }
192static inline unsigned int work_static(struct work_struct *work) { return 0; }
193#endif
194
195/*
196 * initialize all of a work item in one go
197 *
198 * NOTE! No point in using "atomic_long_set()": using a direct
199 * assignment of the work data initializer allows the compiler
200 * to generate better code.
201 */
202#ifdef CONFIG_LOCKDEP
203#define __INIT_WORK(_work, _func, _onstack)				\
204	do {								\
205		static struct lock_class_key __key;			\
206									\
207		__init_work((_work), _onstack);				\
208		(_work)->data = (atomic_long_t) WORK_DATA_INIT();	\
209		lockdep_init_map(&(_work)->lockdep_map, #_work, &__key, 0); \
210		INIT_LIST_HEAD(&(_work)->entry);			\
211		(_work)->func = (_func);				\
212	} while (0)
213#else
214#define __INIT_WORK(_work, _func, _onstack)				\
215	do {								\
216		__init_work((_work), _onstack);				\
217		(_work)->data = (atomic_long_t) WORK_DATA_INIT();	\
218		INIT_LIST_HEAD(&(_work)->entry);			\
219		(_work)->func = (_func);				\
220	} while (0)
221#endif
222
223#define INIT_WORK(_work, _func)						\
224	__INIT_WORK((_work), (_func), 0)
225
226#define INIT_WORK_ONSTACK(_work, _func)					\
227	__INIT_WORK((_work), (_func), 1)
228
229#define __INIT_DELAYED_WORK(_work, _func, _tflags)			\
230	do {								\
231		INIT_WORK(&(_work)->work, (_func));			\
232		__setup_timer(&(_work)->timer, delayed_work_timer_fn,	\
233			      (unsigned long)(_work),			\
234			      (_tflags) | TIMER_IRQSAFE);		\
235	} while (0)
236
237#define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags)		\
238	do {								\
239		INIT_WORK_ONSTACK(&(_work)->work, (_func));		\
240		__setup_timer_on_stack(&(_work)->timer,			\
241				       delayed_work_timer_fn,		\
242				       (unsigned long)(_work),		\
243				       (_tflags) | TIMER_IRQSAFE);	\
244	} while (0)
245
246#define INIT_DELAYED_WORK(_work, _func)					\
247	__INIT_DELAYED_WORK(_work, _func, 0)
248
249#define INIT_DELAYED_WORK_ONSTACK(_work, _func)				\
250	__INIT_DELAYED_WORK_ONSTACK(_work, _func, 0)
251
252#define INIT_DEFERRABLE_WORK(_work, _func)				\
253	__INIT_DELAYED_WORK(_work, _func, TIMER_DEFERRABLE)
254
255#define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func)			\
256	__INIT_DELAYED_WORK_ONSTACK(_work, _func, TIMER_DEFERRABLE)
257
258/**
259 * work_pending - Find out whether a work item is currently pending
260 * @work: The work item in question
261 */
262#define work_pending(work) \
263	test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
264
265/**
266 * delayed_work_pending - Find out whether a delayable work item is currently
267 * pending
268 * @work: The work item in question
269 */
270#define delayed_work_pending(w) \
271	work_pending(&(w)->work)
272
273/*
274 * Workqueue flags and constants.  For details, please refer to
275 * Documentation/workqueue.txt.
276 */
277enum {
278	WQ_UNBOUND		= 1 << 1, /* not bound to any cpu */
279	WQ_FREEZABLE		= 1 << 2, /* freeze during suspend */
280	WQ_MEM_RECLAIM		= 1 << 3, /* may be used for memory reclaim */
281	WQ_HIGHPRI		= 1 << 4, /* high priority */
282	WQ_CPU_INTENSIVE	= 1 << 5, /* cpu intensive workqueue */
283	WQ_SYSFS		= 1 << 6, /* visible in sysfs, see wq_sysfs_register() */
284
285	/*
286	 * Per-cpu workqueues are generally preferred because they tend to
287	 * show better performance thanks to cache locality.  Per-cpu
288	 * workqueues exclude the scheduler from choosing the CPU to
289	 * execute the worker threads, which has an unfortunate side effect
290	 * of increasing power consumption.
291	 *
292	 * The scheduler considers a CPU idle if it doesn't have any task
293	 * to execute and tries to keep idle cores idle to conserve power;
294	 * however, for example, a per-cpu work item scheduled from an
295	 * interrupt handler on an idle CPU will force the scheduler to
296	 * excute the work item on that CPU breaking the idleness, which in
297	 * turn may lead to more scheduling choices which are sub-optimal
298	 * in terms of power consumption.
299	 *
300	 * Workqueues marked with WQ_POWER_EFFICIENT are per-cpu by default
301	 * but become unbound if workqueue.power_efficient kernel param is
302	 * specified.  Per-cpu workqueues which are identified to
303	 * contribute significantly to power-consumption are identified and
304	 * marked with this flag and enabling the power_efficient mode
305	 * leads to noticeable power saving at the cost of small
306	 * performance disadvantage.
307	 *
308	 * http://thread.gmane.org/gmane.linux.kernel/1480396
309	 */
310	WQ_POWER_EFFICIENT	= 1 << 7,
311
312	__WQ_DRAINING		= 1 << 16, /* internal: workqueue is draining */
313	__WQ_ORDERED		= 1 << 17, /* internal: workqueue is ordered */
314
315	WQ_MAX_ACTIVE		= 512,	  /* I like 512, better ideas? */
316	WQ_MAX_UNBOUND_PER_CPU	= 4,	  /* 4 * #cpus for unbound wq */
317	WQ_DFL_ACTIVE		= WQ_MAX_ACTIVE / 2,
318};
319
320/* unbound wq's aren't per-cpu, scale max_active according to #cpus */
321#define WQ_UNBOUND_MAX_ACTIVE	\
322	max_t(int, WQ_MAX_ACTIVE, num_possible_cpus() * WQ_MAX_UNBOUND_PER_CPU)
323
324/*
325 * System-wide workqueues which are always present.
326 *
327 * system_wq is the one used by schedule[_delayed]_work[_on]().
328 * Multi-CPU multi-threaded.  There are users which expect relatively
329 * short queue flush time.  Don't queue works which can run for too
330 * long.
331 *
332 * system_highpri_wq is similar to system_wq but for work items which
333 * require WQ_HIGHPRI.
334 *
335 * system_long_wq is similar to system_wq but may host long running
336 * works.  Queue flushing might take relatively long.
337 *
338 * system_unbound_wq is unbound workqueue.  Workers are not bound to
339 * any specific CPU, not concurrency managed, and all queued works are
340 * executed immediately as long as max_active limit is not reached and
341 * resources are available.
342 *
343 * system_freezable_wq is equivalent to system_wq except that it's
344 * freezable.
345 *
346 * *_power_efficient_wq are inclined towards saving power and converted
347 * into WQ_UNBOUND variants if 'wq_power_efficient' is enabled; otherwise,
348 * they are same as their non-power-efficient counterparts - e.g.
349 * system_power_efficient_wq is identical to system_wq if
350 * 'wq_power_efficient' is disabled.  See WQ_POWER_EFFICIENT for more info.
351 */
352extern struct workqueue_struct *system_wq;
353extern struct workqueue_struct *system_highpri_wq;
354extern struct workqueue_struct *system_long_wq;
355extern struct workqueue_struct *system_unbound_wq;
356extern struct workqueue_struct *system_freezable_wq;
357extern struct workqueue_struct *system_power_efficient_wq;
358extern struct workqueue_struct *system_freezable_power_efficient_wq;
359
360extern struct workqueue_struct *
361__alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active,
362	struct lock_class_key *key, const char *lock_name, ...) __printf(1, 6);
363
364/**
365 * alloc_workqueue - allocate a workqueue
366 * @fmt: printf format for the name of the workqueue
367 * @flags: WQ_* flags
368 * @max_active: max in-flight work items, 0 for default
369 * @args: args for @fmt
370 *
371 * Allocate a workqueue with the specified parameters.  For detailed
372 * information on WQ_* flags, please refer to Documentation/workqueue.txt.
373 *
374 * The __lock_name macro dance is to guarantee that single lock_class_key
375 * doesn't end up with different namesm, which isn't allowed by lockdep.
376 *
377 * RETURNS:
378 * Pointer to the allocated workqueue on success, %NULL on failure.
379 */
380#ifdef CONFIG_LOCKDEP
381#define alloc_workqueue(fmt, flags, max_active, args...)		\
382({									\
383	static struct lock_class_key __key;				\
384	const char *__lock_name;					\
385									\
386	__lock_name = #fmt#args;					\
387									\
388	__alloc_workqueue_key((fmt), (flags), (max_active),		\
389			      &__key, __lock_name, ##args);		\
390})
391#else
392#define alloc_workqueue(fmt, flags, max_active, args...)		\
393	__alloc_workqueue_key((fmt), (flags), (max_active),		\
394			      NULL, NULL, ##args)
395#endif
396
397/**
398 * alloc_ordered_workqueue - allocate an ordered workqueue
399 * @fmt: printf format for the name of the workqueue
400 * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
401 * @args: args for @fmt
402 *
403 * Allocate an ordered workqueue.  An ordered workqueue executes at
404 * most one work item at any given time in the queued order.  They are
405 * implemented as unbound workqueues with @max_active of one.
406 *
407 * RETURNS:
408 * Pointer to the allocated workqueue on success, %NULL on failure.
409 */
410#define alloc_ordered_workqueue(fmt, flags, args...)			\
411	alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | (flags), 1, ##args)
412
413#define create_workqueue(name)						\
414	alloc_workqueue("%s", WQ_MEM_RECLAIM, 1, (name))
415#define create_freezable_workqueue(name)				\
416	alloc_workqueue("%s", WQ_FREEZABLE | WQ_UNBOUND | WQ_MEM_RECLAIM, \
417			1, (name))
418#define create_singlethread_workqueue(name)				\
419	alloc_ordered_workqueue("%s", WQ_MEM_RECLAIM, name)
420
421extern void destroy_workqueue(struct workqueue_struct *wq);
422
423struct workqueue_attrs *alloc_workqueue_attrs(gfp_t gfp_mask);
424void free_workqueue_attrs(struct workqueue_attrs *attrs);
425int apply_workqueue_attrs(struct workqueue_struct *wq,
426			  const struct workqueue_attrs *attrs);
427
428extern bool queue_work_on(int cpu, struct workqueue_struct *wq,
429			struct work_struct *work);
430extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
431			struct delayed_work *work, unsigned long delay);
432extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
433			struct delayed_work *dwork, unsigned long delay);
434
435extern void flush_workqueue(struct workqueue_struct *wq);
436extern void drain_workqueue(struct workqueue_struct *wq);
437extern void flush_scheduled_work(void);
438
439extern int schedule_on_each_cpu(work_func_t func);
440
441int execute_in_process_context(work_func_t fn, struct execute_work *);
442
443extern bool flush_work(struct work_struct *work);
444extern bool cancel_work_sync(struct work_struct *work);
445
446extern bool flush_delayed_work(struct delayed_work *dwork);
447extern bool cancel_delayed_work(struct delayed_work *dwork);
448extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
449
450extern void workqueue_set_max_active(struct workqueue_struct *wq,
451				     int max_active);
452extern bool current_is_workqueue_rescuer(void);
453extern bool workqueue_congested(int cpu, struct workqueue_struct *wq);
454extern unsigned int work_busy(struct work_struct *work);
455extern __printf(1, 2) void set_worker_desc(const char *fmt, ...);
456extern void print_worker_info(const char *log_lvl, struct task_struct *task);
457extern void show_workqueue_state(void);
458
459/**
460 * queue_work - queue work on a workqueue
461 * @wq: workqueue to use
462 * @work: work to queue
463 *
464 * Returns %false if @work was already on a queue, %true otherwise.
465 *
466 * We queue the work to the CPU on which it was submitted, but if the CPU dies
467 * it can be processed by another CPU.
468 */
469static inline bool queue_work(struct workqueue_struct *wq,
470			      struct work_struct *work)
471{
472	return queue_work_on(WORK_CPU_UNBOUND, wq, work);
473}
474
475/**
476 * queue_delayed_work - queue work on a workqueue after delay
477 * @wq: workqueue to use
478 * @dwork: delayable work to queue
479 * @delay: number of jiffies to wait before queueing
480 *
481 * Equivalent to queue_delayed_work_on() but tries to use the local CPU.
482 */
483static inline bool queue_delayed_work(struct workqueue_struct *wq,
484				      struct delayed_work *dwork,
485				      unsigned long delay)
486{
487	return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
488}
489
490/**
491 * mod_delayed_work - modify delay of or queue a delayed work
492 * @wq: workqueue to use
493 * @dwork: work to queue
494 * @delay: number of jiffies to wait before queueing
495 *
496 * mod_delayed_work_on() on local CPU.
497 */
498static inline bool mod_delayed_work(struct workqueue_struct *wq,
499				    struct delayed_work *dwork,
500				    unsigned long delay)
501{
502	return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
503}
504
505/**
506 * schedule_work_on - put work task on a specific cpu
507 * @cpu: cpu to put the work task on
508 * @work: job to be done
509 *
510 * This puts a job on a specific cpu
511 */
512static inline bool schedule_work_on(int cpu, struct work_struct *work)
513{
514	return queue_work_on(cpu, system_wq, work);
515}
516
517/**
518 * schedule_work - put work task in global workqueue
519 * @work: job to be done
520 *
521 * Returns %false if @work was already on the kernel-global workqueue and
522 * %true otherwise.
523 *
524 * This puts a job in the kernel-global workqueue if it was not already
525 * queued and leaves it in the same position on the kernel-global
526 * workqueue otherwise.
527 */
528static inline bool schedule_work(struct work_struct *work)
529{
530	return queue_work(system_wq, work);
531}
532
533/**
534 * schedule_delayed_work_on - queue work in global workqueue on CPU after delay
535 * @cpu: cpu to use
536 * @dwork: job to be done
537 * @delay: number of jiffies to wait
538 *
539 * After waiting for a given time this puts a job in the kernel-global
540 * workqueue on the specified CPU.
541 */
542static inline bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork,
543					    unsigned long delay)
544{
545	return queue_delayed_work_on(cpu, system_wq, dwork, delay);
546}
547
548/**
549 * schedule_delayed_work - put work task in global workqueue after delay
550 * @dwork: job to be done
551 * @delay: number of jiffies to wait or 0 for immediate execution
552 *
553 * After waiting for a given time this puts a job in the kernel-global
554 * workqueue.
555 */
556static inline bool schedule_delayed_work(struct delayed_work *dwork,
557					 unsigned long delay)
558{
559	return queue_delayed_work(system_wq, dwork, delay);
560}
561
562/**
563 * keventd_up - is workqueue initialized yet?
564 */
565static inline bool keventd_up(void)
566{
567	return system_wq != NULL;
568}
569
570#ifndef CONFIG_SMP
571static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
572{
573	return fn(arg);
574}
575#else
576long work_on_cpu(int cpu, long (*fn)(void *), void *arg);
577#endif /* CONFIG_SMP */
578
579#ifdef CONFIG_FREEZER
580extern void freeze_workqueues_begin(void);
581extern bool freeze_workqueues_busy(void);
582extern void thaw_workqueues(void);
583#endif /* CONFIG_FREEZER */
584
585#ifdef CONFIG_SYSFS
586int workqueue_sysfs_register(struct workqueue_struct *wq);
587#else	/* CONFIG_SYSFS */
588static inline int workqueue_sysfs_register(struct workqueue_struct *wq)
589{ return 0; }
590#endif	/* CONFIG_SYSFS */
591
592#endif
593