workqueue.h 21 KB

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  1. /*
  2. * workqueue.h --- work queue handling for Linux.
  3. */
  4. #ifndef _LINUX_WORKQUEUE_H
  5. #define _LINUX_WORKQUEUE_H
  6. #include <linux/timer.h>
  7. #include <linux/linkage.h>
  8. #include <linux/bitops.h>
  9. #include <linux/lockdep.h>
  10. #include <linux/threads.h>
  11. #include <linux/atomic.h>
  12. #include <linux/cpumask.h>
  13. struct workqueue_struct;
  14. struct work_struct;
  15. typedef void (*work_func_t)(struct work_struct *work);
  16. void delayed_work_timer_fn(unsigned long __data);
  17. /*
  18. * The first word is the work queue pointer and the flags rolled into
  19. * one
  20. */
  21. #define work_data_bits(work) ((unsigned long *)(&(work)->data))
  22. enum {
  23. WORK_STRUCT_PENDING_BIT = 0, /* work item is pending execution */
  24. WORK_STRUCT_DELAYED_BIT = 1, /* work item is delayed */
  25. WORK_STRUCT_PWQ_BIT = 2, /* data points to pwq */
  26. WORK_STRUCT_LINKED_BIT = 3, /* next work is linked to this one */
  27. #ifdef CONFIG_DEBUG_OBJECTS_WORK
  28. WORK_STRUCT_STATIC_BIT = 4, /* static initializer (debugobjects) */
  29. WORK_STRUCT_COLOR_SHIFT = 5, /* color for workqueue flushing */
  30. #else
  31. WORK_STRUCT_COLOR_SHIFT = 4, /* color for workqueue flushing */
  32. #endif
  33. WORK_STRUCT_COLOR_BITS = 4,
  34. WORK_STRUCT_PENDING = 1 << WORK_STRUCT_PENDING_BIT,
  35. WORK_STRUCT_DELAYED = 1 << WORK_STRUCT_DELAYED_BIT,
  36. WORK_STRUCT_PWQ = 1 << WORK_STRUCT_PWQ_BIT,
  37. WORK_STRUCT_LINKED = 1 << WORK_STRUCT_LINKED_BIT,
  38. #ifdef CONFIG_DEBUG_OBJECTS_WORK
  39. WORK_STRUCT_STATIC = 1 << WORK_STRUCT_STATIC_BIT,
  40. #else
  41. WORK_STRUCT_STATIC = 0,
  42. #endif
  43. /*
  44. * The last color is no color used for works which don't
  45. * participate in workqueue flushing.
  46. */
  47. WORK_NR_COLORS = (1 << WORK_STRUCT_COLOR_BITS) - 1,
  48. WORK_NO_COLOR = WORK_NR_COLORS,
  49. /* not bound to any CPU, prefer the local CPU */
  50. WORK_CPU_UNBOUND = NR_CPUS,
  51. /*
  52. * Reserve 7 bits off of pwq pointer w/ debugobjects turned off.
  53. * This makes pwqs aligned to 256 bytes and allows 15 workqueue
  54. * flush colors.
  55. */
  56. WORK_STRUCT_FLAG_BITS = WORK_STRUCT_COLOR_SHIFT +
  57. WORK_STRUCT_COLOR_BITS,
  58. /* data contains off-queue information when !WORK_STRUCT_PWQ */
  59. WORK_OFFQ_FLAG_BASE = WORK_STRUCT_COLOR_SHIFT,
  60. __WORK_OFFQ_CANCELING = WORK_OFFQ_FLAG_BASE,
  61. WORK_OFFQ_CANCELING = (1 << __WORK_OFFQ_CANCELING),
  62. /*
  63. * When a work item is off queue, its high bits point to the last
  64. * pool it was on. Cap at 31 bits and use the highest number to
  65. * indicate that no pool is associated.
  66. */
  67. WORK_OFFQ_FLAG_BITS = 1,
  68. WORK_OFFQ_POOL_SHIFT = WORK_OFFQ_FLAG_BASE + WORK_OFFQ_FLAG_BITS,
  69. WORK_OFFQ_LEFT = BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT,
  70. WORK_OFFQ_POOL_BITS = WORK_OFFQ_LEFT <= 31 ? WORK_OFFQ_LEFT : 31,
  71. WORK_OFFQ_POOL_NONE = (1LU << WORK_OFFQ_POOL_BITS) - 1,
  72. /* convenience constants */
  73. WORK_STRUCT_FLAG_MASK = (1UL << WORK_STRUCT_FLAG_BITS) - 1,
  74. WORK_STRUCT_WQ_DATA_MASK = ~WORK_STRUCT_FLAG_MASK,
  75. WORK_STRUCT_NO_POOL = (unsigned long)WORK_OFFQ_POOL_NONE << WORK_OFFQ_POOL_SHIFT,
  76. /* bit mask for work_busy() return values */
  77. WORK_BUSY_PENDING = 1 << 0,
  78. WORK_BUSY_RUNNING = 1 << 1,
  79. /* maximum string length for set_worker_desc() */
  80. WORKER_DESC_LEN = 24,
  81. };
  82. struct work_struct {
  83. atomic_long_t data;
  84. struct list_head entry;
  85. work_func_t func;
  86. #ifdef CONFIG_LOCKDEP
  87. struct lockdep_map lockdep_map;
  88. #endif
  89. };
  90. #define WORK_DATA_INIT() ATOMIC_LONG_INIT(WORK_STRUCT_NO_POOL)
  91. #define WORK_DATA_STATIC_INIT() \
  92. ATOMIC_LONG_INIT(WORK_STRUCT_NO_POOL | WORK_STRUCT_STATIC)
  93. struct delayed_work {
  94. struct work_struct work;
  95. struct timer_list timer;
  96. /* target workqueue and CPU ->timer uses to queue ->work */
  97. struct workqueue_struct *wq;
  98. int cpu;
  99. };
  100. /*
  101. * A struct for workqueue attributes. This can be used to change
  102. * attributes of an unbound workqueue.
  103. *
  104. * Unlike other fields, ->no_numa isn't a property of a worker_pool. It
  105. * only modifies how apply_workqueue_attrs() select pools and thus doesn't
  106. * participate in pool hash calculations or equality comparisons.
  107. */
  108. struct workqueue_attrs {
  109. int nice; /* nice level */
  110. cpumask_var_t cpumask; /* allowed CPUs */
  111. bool no_numa; /* disable NUMA affinity */
  112. };
  113. static inline struct delayed_work *to_delayed_work(struct work_struct *work)
  114. {
  115. return container_of(work, struct delayed_work, work);
  116. }
  117. struct execute_work {
  118. struct work_struct work;
  119. };
  120. #ifdef CONFIG_LOCKDEP
  121. /*
  122. * NB: because we have to copy the lockdep_map, setting _key
  123. * here is required, otherwise it could get initialised to the
  124. * copy of the lockdep_map!
  125. */
  126. #define __WORK_INIT_LOCKDEP_MAP(n, k) \
  127. .lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k),
  128. #else
  129. #define __WORK_INIT_LOCKDEP_MAP(n, k)
  130. #endif
  131. #define __WORK_INITIALIZER(n, f) { \
  132. .data = WORK_DATA_STATIC_INIT(), \
  133. .entry = { &(n).entry, &(n).entry }, \
  134. .func = (f), \
  135. __WORK_INIT_LOCKDEP_MAP(#n, &(n)) \
  136. }
  137. #define __DELAYED_WORK_INITIALIZER(n, f, tflags) { \
  138. .work = __WORK_INITIALIZER((n).work, (f)), \
  139. .timer = __TIMER_INITIALIZER(delayed_work_timer_fn, \
  140. 0, (unsigned long)&(n), \
  141. (tflags) | TIMER_IRQSAFE), \
  142. }
  143. #define DECLARE_WORK(n, f) \
  144. struct work_struct n = __WORK_INITIALIZER(n, f)
  145. #define DECLARE_DELAYED_WORK(n, f) \
  146. struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, 0)
  147. #define DECLARE_DEFERRABLE_WORK(n, f) \
  148. struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, TIMER_DEFERRABLE)
  149. #ifdef CONFIG_DEBUG_OBJECTS_WORK
  150. extern void __init_work(struct work_struct *work, int onstack);
  151. extern void destroy_work_on_stack(struct work_struct *work);
  152. extern void destroy_delayed_work_on_stack(struct delayed_work *work);
  153. static inline unsigned int work_static(struct work_struct *work)
  154. {
  155. return *work_data_bits(work) & WORK_STRUCT_STATIC;
  156. }
  157. #else
  158. static inline void __init_work(struct work_struct *work, int onstack) { }
  159. static inline void destroy_work_on_stack(struct work_struct *work) { }
  160. static inline void destroy_delayed_work_on_stack(struct delayed_work *work) { }
  161. static inline unsigned int work_static(struct work_struct *work) { return 0; }
  162. #endif
  163. /*
  164. * initialize all of a work item in one go
  165. *
  166. * NOTE! No point in using "atomic_long_set()": using a direct
  167. * assignment of the work data initializer allows the compiler
  168. * to generate better code.
  169. */
  170. #ifdef CONFIG_LOCKDEP
  171. #define __INIT_WORK(_work, _func, _onstack) \
  172. do { \
  173. static struct lock_class_key __key; \
  174. \
  175. __init_work((_work), _onstack); \
  176. (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
  177. lockdep_init_map(&(_work)->lockdep_map, #_work, &__key, 0); \
  178. INIT_LIST_HEAD(&(_work)->entry); \
  179. (_work)->func = (_func); \
  180. } while (0)
  181. #else
  182. #define __INIT_WORK(_work, _func, _onstack) \
  183. do { \
  184. __init_work((_work), _onstack); \
  185. (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
  186. INIT_LIST_HEAD(&(_work)->entry); \
  187. (_work)->func = (_func); \
  188. } while (0)
  189. #endif
  190. #define INIT_WORK(_work, _func) \
  191. __INIT_WORK((_work), (_func), 0)
  192. #define INIT_WORK_ONSTACK(_work, _func) \
  193. __INIT_WORK((_work), (_func), 1)
  194. #define __INIT_DELAYED_WORK(_work, _func, _tflags) \
  195. do { \
  196. INIT_WORK(&(_work)->work, (_func)); \
  197. __setup_timer(&(_work)->timer, delayed_work_timer_fn, \
  198. (unsigned long)(_work), \
  199. (_tflags) | TIMER_IRQSAFE); \
  200. } while (0)
  201. #define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags) \
  202. do { \
  203. INIT_WORK_ONSTACK(&(_work)->work, (_func)); \
  204. __setup_timer_on_stack(&(_work)->timer, \
  205. delayed_work_timer_fn, \
  206. (unsigned long)(_work), \
  207. (_tflags) | TIMER_IRQSAFE); \
  208. } while (0)
  209. #define INIT_DELAYED_WORK(_work, _func) \
  210. __INIT_DELAYED_WORK(_work, _func, 0)
  211. #define INIT_DELAYED_WORK_ONSTACK(_work, _func) \
  212. __INIT_DELAYED_WORK_ONSTACK(_work, _func, 0)
  213. #define INIT_DEFERRABLE_WORK(_work, _func) \
  214. __INIT_DELAYED_WORK(_work, _func, TIMER_DEFERRABLE)
  215. #define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func) \
  216. __INIT_DELAYED_WORK_ONSTACK(_work, _func, TIMER_DEFERRABLE)
  217. /**
  218. * work_pending - Find out whether a work item is currently pending
  219. * @work: The work item in question
  220. */
  221. #define work_pending(work) \
  222. test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
  223. /**
  224. * delayed_work_pending - Find out whether a delayable work item is currently
  225. * pending
  226. * @w: The work item in question
  227. */
  228. #define delayed_work_pending(w) \
  229. work_pending(&(w)->work)
  230. /*
  231. * Workqueue flags and constants. For details, please refer to
  232. * Documentation/workqueue.txt.
  233. */
  234. enum {
  235. WQ_UNBOUND = 1 << 1, /* not bound to any cpu */
  236. WQ_FREEZABLE = 1 << 2, /* freeze during suspend */
  237. WQ_MEM_RECLAIM = 1 << 3, /* may be used for memory reclaim */
  238. WQ_HIGHPRI = 1 << 4, /* high priority */
  239. WQ_CPU_INTENSIVE = 1 << 5, /* cpu intensive workqueue */
  240. WQ_SYSFS = 1 << 6, /* visible in sysfs, see wq_sysfs_register() */
  241. /*
  242. * Per-cpu workqueues are generally preferred because they tend to
  243. * show better performance thanks to cache locality. Per-cpu
  244. * workqueues exclude the scheduler from choosing the CPU to
  245. * execute the worker threads, which has an unfortunate side effect
  246. * of increasing power consumption.
  247. *
  248. * The scheduler considers a CPU idle if it doesn't have any task
  249. * to execute and tries to keep idle cores idle to conserve power;
  250. * however, for example, a per-cpu work item scheduled from an
  251. * interrupt handler on an idle CPU will force the scheduler to
  252. * excute the work item on that CPU breaking the idleness, which in
  253. * turn may lead to more scheduling choices which are sub-optimal
  254. * in terms of power consumption.
  255. *
  256. * Workqueues marked with WQ_POWER_EFFICIENT are per-cpu by default
  257. * but become unbound if workqueue.power_efficient kernel param is
  258. * specified. Per-cpu workqueues which are identified to
  259. * contribute significantly to power-consumption are identified and
  260. * marked with this flag and enabling the power_efficient mode
  261. * leads to noticeable power saving at the cost of small
  262. * performance disadvantage.
  263. *
  264. * http://thread.gmane.org/gmane.linux.kernel/1480396
  265. */
  266. WQ_POWER_EFFICIENT = 1 << 7,
  267. __WQ_DRAINING = 1 << 16, /* internal: workqueue is draining */
  268. __WQ_ORDERED = 1 << 17, /* internal: workqueue is ordered */
  269. __WQ_LEGACY = 1 << 18, /* internal: create*_workqueue() */
  270. WQ_MAX_ACTIVE = 512, /* I like 512, better ideas? */
  271. WQ_MAX_UNBOUND_PER_CPU = 4, /* 4 * #cpus for unbound wq */
  272. WQ_DFL_ACTIVE = WQ_MAX_ACTIVE / 2,
  273. };
  274. /* unbound wq's aren't per-cpu, scale max_active according to #cpus */
  275. #define WQ_UNBOUND_MAX_ACTIVE \
  276. max_t(int, WQ_MAX_ACTIVE, num_possible_cpus() * WQ_MAX_UNBOUND_PER_CPU)
  277. /*
  278. * System-wide workqueues which are always present.
  279. *
  280. * system_wq is the one used by schedule[_delayed]_work[_on]().
  281. * Multi-CPU multi-threaded. There are users which expect relatively
  282. * short queue flush time. Don't queue works which can run for too
  283. * long.
  284. *
  285. * system_highpri_wq is similar to system_wq but for work items which
  286. * require WQ_HIGHPRI.
  287. *
  288. * system_long_wq is similar to system_wq but may host long running
  289. * works. Queue flushing might take relatively long.
  290. *
  291. * system_unbound_wq is unbound workqueue. Workers are not bound to
  292. * any specific CPU, not concurrency managed, and all queued works are
  293. * executed immediately as long as max_active limit is not reached and
  294. * resources are available.
  295. *
  296. * system_freezable_wq is equivalent to system_wq except that it's
  297. * freezable.
  298. *
  299. * *_power_efficient_wq are inclined towards saving power and converted
  300. * into WQ_UNBOUND variants if 'wq_power_efficient' is enabled; otherwise,
  301. * they are same as their non-power-efficient counterparts - e.g.
  302. * system_power_efficient_wq is identical to system_wq if
  303. * 'wq_power_efficient' is disabled. See WQ_POWER_EFFICIENT for more info.
  304. */
  305. extern struct workqueue_struct *system_wq;
  306. extern struct workqueue_struct *system_highpri_wq;
  307. extern struct workqueue_struct *system_long_wq;
  308. extern struct workqueue_struct *system_unbound_wq;
  309. extern struct workqueue_struct *system_freezable_wq;
  310. extern struct workqueue_struct *system_power_efficient_wq;
  311. extern struct workqueue_struct *system_freezable_power_efficient_wq;
  312. extern struct workqueue_struct *
  313. __alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active,
  314. struct lock_class_key *key, const char *lock_name, ...) __printf(1, 6);
  315. /**
  316. * alloc_workqueue - allocate a workqueue
  317. * @fmt: printf format for the name of the workqueue
  318. * @flags: WQ_* flags
  319. * @max_active: max in-flight work items, 0 for default
  320. * @args...: args for @fmt
  321. *
  322. * Allocate a workqueue with the specified parameters. For detailed
  323. * information on WQ_* flags, please refer to Documentation/workqueue.txt.
  324. *
  325. * The __lock_name macro dance is to guarantee that single lock_class_key
  326. * doesn't end up with different namesm, which isn't allowed by lockdep.
  327. *
  328. * RETURNS:
  329. * Pointer to the allocated workqueue on success, %NULL on failure.
  330. */
  331. #ifdef CONFIG_LOCKDEP
  332. #define alloc_workqueue(fmt, flags, max_active, args...) \
  333. ({ \
  334. static struct lock_class_key __key; \
  335. const char *__lock_name; \
  336. \
  337. __lock_name = #fmt#args; \
  338. \
  339. __alloc_workqueue_key((fmt), (flags), (max_active), \
  340. &__key, __lock_name, ##args); \
  341. })
  342. #else
  343. #define alloc_workqueue(fmt, flags, max_active, args...) \
  344. __alloc_workqueue_key((fmt), (flags), (max_active), \
  345. NULL, NULL, ##args)
  346. #endif
  347. /**
  348. * alloc_ordered_workqueue - allocate an ordered workqueue
  349. * @fmt: printf format for the name of the workqueue
  350. * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
  351. * @args...: args for @fmt
  352. *
  353. * Allocate an ordered workqueue. An ordered workqueue executes at
  354. * most one work item at any given time in the queued order. They are
  355. * implemented as unbound workqueues with @max_active of one.
  356. *
  357. * RETURNS:
  358. * Pointer to the allocated workqueue on success, %NULL on failure.
  359. */
  360. #define alloc_ordered_workqueue(fmt, flags, args...) \
  361. alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | (flags), 1, ##args)
  362. #define create_workqueue(name) \
  363. alloc_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, 1, (name))
  364. #define create_freezable_workqueue(name) \
  365. alloc_workqueue("%s", __WQ_LEGACY | WQ_FREEZABLE | WQ_UNBOUND | \
  366. WQ_MEM_RECLAIM, 1, (name))
  367. #define create_singlethread_workqueue(name) \
  368. alloc_ordered_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, name)
  369. extern void destroy_workqueue(struct workqueue_struct *wq);
  370. struct workqueue_attrs *alloc_workqueue_attrs(gfp_t gfp_mask);
  371. void free_workqueue_attrs(struct workqueue_attrs *attrs);
  372. int apply_workqueue_attrs(struct workqueue_struct *wq,
  373. const struct workqueue_attrs *attrs);
  374. int workqueue_set_unbound_cpumask(cpumask_var_t cpumask);
  375. extern bool queue_work_on(int cpu, struct workqueue_struct *wq,
  376. struct work_struct *work);
  377. extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
  378. struct delayed_work *work, unsigned long delay);
  379. extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
  380. struct delayed_work *dwork, unsigned long delay);
  381. extern void flush_workqueue(struct workqueue_struct *wq);
  382. extern void drain_workqueue(struct workqueue_struct *wq);
  383. extern int schedule_on_each_cpu(work_func_t func);
  384. int execute_in_process_context(work_func_t fn, struct execute_work *);
  385. extern bool flush_work(struct work_struct *work);
  386. extern bool cancel_work(struct work_struct *work);
  387. extern bool cancel_work_sync(struct work_struct *work);
  388. extern bool flush_delayed_work(struct delayed_work *dwork);
  389. extern bool cancel_delayed_work(struct delayed_work *dwork);
  390. extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
  391. extern void workqueue_set_max_active(struct workqueue_struct *wq,
  392. int max_active);
  393. extern bool current_is_workqueue_rescuer(void);
  394. extern bool workqueue_congested(int cpu, struct workqueue_struct *wq);
  395. extern unsigned int work_busy(struct work_struct *work);
  396. extern __printf(1, 2) void set_worker_desc(const char *fmt, ...);
  397. extern void print_worker_info(const char *log_lvl, struct task_struct *task);
  398. extern void show_workqueue_state(void);
  399. /**
  400. * queue_work - queue work on a workqueue
  401. * @wq: workqueue to use
  402. * @work: work to queue
  403. *
  404. * Returns %false if @work was already on a queue, %true otherwise.
  405. *
  406. * We queue the work to the CPU on which it was submitted, but if the CPU dies
  407. * it can be processed by another CPU.
  408. */
  409. static inline bool queue_work(struct workqueue_struct *wq,
  410. struct work_struct *work)
  411. {
  412. return queue_work_on(WORK_CPU_UNBOUND, wq, work);
  413. }
  414. /**
  415. * queue_delayed_work - queue work on a workqueue after delay
  416. * @wq: workqueue to use
  417. * @dwork: delayable work to queue
  418. * @delay: number of jiffies to wait before queueing
  419. *
  420. * Equivalent to queue_delayed_work_on() but tries to use the local CPU.
  421. */
  422. static inline bool queue_delayed_work(struct workqueue_struct *wq,
  423. struct delayed_work *dwork,
  424. unsigned long delay)
  425. {
  426. return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
  427. }
  428. /**
  429. * mod_delayed_work - modify delay of or queue a delayed work
  430. * @wq: workqueue to use
  431. * @dwork: work to queue
  432. * @delay: number of jiffies to wait before queueing
  433. *
  434. * mod_delayed_work_on() on local CPU.
  435. */
  436. static inline bool mod_delayed_work(struct workqueue_struct *wq,
  437. struct delayed_work *dwork,
  438. unsigned long delay)
  439. {
  440. return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
  441. }
  442. /**
  443. * schedule_work_on - put work task on a specific cpu
  444. * @cpu: cpu to put the work task on
  445. * @work: job to be done
  446. *
  447. * This puts a job on a specific cpu
  448. */
  449. static inline bool schedule_work_on(int cpu, struct work_struct *work)
  450. {
  451. return queue_work_on(cpu, system_wq, work);
  452. }
  453. /**
  454. * schedule_work - put work task in global workqueue
  455. * @work: job to be done
  456. *
  457. * Returns %false if @work was already on the kernel-global workqueue and
  458. * %true otherwise.
  459. *
  460. * This puts a job in the kernel-global workqueue if it was not already
  461. * queued and leaves it in the same position on the kernel-global
  462. * workqueue otherwise.
  463. */
  464. static inline bool schedule_work(struct work_struct *work)
  465. {
  466. return queue_work(system_wq, work);
  467. }
  468. /**
  469. * flush_scheduled_work - ensure that any scheduled work has run to completion.
  470. *
  471. * Forces execution of the kernel-global workqueue and blocks until its
  472. * completion.
  473. *
  474. * Think twice before calling this function! It's very easy to get into
  475. * trouble if you don't take great care. Either of the following situations
  476. * will lead to deadlock:
  477. *
  478. * One of the work items currently on the workqueue needs to acquire
  479. * a lock held by your code or its caller.
  480. *
  481. * Your code is running in the context of a work routine.
  482. *
  483. * They will be detected by lockdep when they occur, but the first might not
  484. * occur very often. It depends on what work items are on the workqueue and
  485. * what locks they need, which you have no control over.
  486. *
  487. * In most situations flushing the entire workqueue is overkill; you merely
  488. * need to know that a particular work item isn't queued and isn't running.
  489. * In such cases you should use cancel_delayed_work_sync() or
  490. * cancel_work_sync() instead.
  491. */
  492. static inline void flush_scheduled_work(void)
  493. {
  494. flush_workqueue(system_wq);
  495. }
  496. /**
  497. * schedule_delayed_work_on - queue work in global workqueue on CPU after delay
  498. * @cpu: cpu to use
  499. * @dwork: job to be done
  500. * @delay: number of jiffies to wait
  501. *
  502. * After waiting for a given time this puts a job in the kernel-global
  503. * workqueue on the specified CPU.
  504. */
  505. static inline bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork,
  506. unsigned long delay)
  507. {
  508. return queue_delayed_work_on(cpu, system_wq, dwork, delay);
  509. }
  510. /**
  511. * schedule_delayed_work - put work task in global workqueue after delay
  512. * @dwork: job to be done
  513. * @delay: number of jiffies to wait or 0 for immediate execution
  514. *
  515. * After waiting for a given time this puts a job in the kernel-global
  516. * workqueue.
  517. */
  518. static inline bool schedule_delayed_work(struct delayed_work *dwork,
  519. unsigned long delay)
  520. {
  521. return queue_delayed_work(system_wq, dwork, delay);
  522. }
  523. #ifndef CONFIG_SMP
  524. static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
  525. {
  526. return fn(arg);
  527. }
  528. #else
  529. long work_on_cpu(int cpu, long (*fn)(void *), void *arg);
  530. #endif /* CONFIG_SMP */
  531. #ifdef CONFIG_FREEZER
  532. extern void freeze_workqueues_begin(void);
  533. extern bool freeze_workqueues_busy(void);
  534. extern void thaw_workqueues(void);
  535. #endif /* CONFIG_FREEZER */
  536. #ifdef CONFIG_SYSFS
  537. int workqueue_sysfs_register(struct workqueue_struct *wq);
  538. #else /* CONFIG_SYSFS */
  539. static inline int workqueue_sysfs_register(struct workqueue_struct *wq)
  540. { return 0; }
  541. #endif /* CONFIG_SYSFS */
  542. #ifdef CONFIG_WQ_WATCHDOG
  543. void wq_watchdog_touch(int cpu);
  544. #else /* CONFIG_WQ_WATCHDOG */
  545. static inline void wq_watchdog_touch(int cpu) { }
  546. #endif /* CONFIG_WQ_WATCHDOG */
  547. #ifdef CONFIG_SMP
  548. int workqueue_prepare_cpu(unsigned int cpu);
  549. int workqueue_online_cpu(unsigned int cpu);
  550. int workqueue_offline_cpu(unsigned int cpu);
  551. #endif
  552. int __init workqueue_init_early(void);
  553. int __init workqueue_init(void);
  554. #endif