include/linux/workqueue.h

   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
  97 struct work_struct {
  98         atomic_long_t data;
  99         struct list_head entry;
 100         work_func_t func;
 101 #ifdef CONFIG_LOCKDEP
 102         struct lockdep_map lockdep_map;
 103 #endif
 104 };
 105
 106 #define WORK_DATA_INIT()        ATOMIC_LONG_INIT(WORK_STRUCT_NO_POOL)
 107 #define WORK_DATA_STATIC_INIT() \
 108         ATOMIC_LONG_INIT(WORK_STRUCT_NO_POOL | WORK_STRUCT_STATIC)
 109
 110 struct delayed_work {
 111         struct work_struct work;
 112         struct timer_list timer;
 113
 114         /* target workqueue and CPU ->timer uses to queue ->work */
 115         struct workqueue_struct *wq;
 116         int cpu;
 117 };
 118
 119 /*
 120  * A struct for workqueue attributes.  This can be used to change
 121  * attributes of an unbound workqueue.
 122  *
 123  * Unlike other fields, ->no_numa isn't a property of a worker_pool.  It
 124  * only modifies how apply_workqueue_attrs() select pools and thus doesn't
 125  * participate in pool hash calculations or equality comparisons.
 126  */
 127 struct workqueue_attrs {
 128         int                     nice;           /* nice level */
 129         cpumask_var_t           cpumask;        /* allowed CPUs */
 130         bool                    no_numa;        /* disable NUMA affinity */
 131 };
 132
 133 static inline struct delayed_work *to_delayed_work(struct work_struct *work)
 134 {
 135         return container_of(work, struct delayed_work, work);
 136 }
 137
 138 struct execute_work {
 139         struct work_struct work;
 140 };
 141
 142 #ifdef CONFIG_LOCKDEP
 143 /*
 144  * NB: because we have to copy the lockdep_map, setting _key
 145  * here is required, otherwise it could get initialised to the
 146  * copy of the lockdep_map!
 147  */
 148 #define __WORK_INIT_LOCKDEP_MAP(n, k) \
 149         .lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k),
 150 #else
 151 #define __WORK_INIT_LOCKDEP_MAP(n, k)
 152 #endif
 153
 154 #define __WORK_INITIALIZER(n, f) {                                      \
 155         .data = WORK_DATA_STATIC_INIT(),                                \
 156         .entry  = { &(n).entry, &(n).entry },                           \
 157         .func = (f),                                                    \
 158         __WORK_INIT_LOCKDEP_MAP(#n, &(n))                               \
 159         }
 160
 161 #define __DELAYED_WORK_INITIALIZER(n, f, tflags) {                      \
 162         .work = __WORK_INITIALIZER((n).work, (f)),                      \
 163         .timer = __TIMER_INITIALIZER(delayed_work_timer_fn,             \
 164                                      0, (unsigned long)&(n),            \
 165                                      (tflags) | TIMER_IRQSAFE),         \
 166         }
 167
 168 #define DECLARE_WORK(n, f)                                              \
 169         struct work_struct n = __WORK_INITIALIZER(n, f)
 170
 171 #define DECLARE_DELAYED_WORK(n, f)                                      \
 172         struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, 0)
 173
 174 #define DECLARE_DEFERRABLE_WORK(n, f)                                   \
 175         struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, TIMER_DEFERRABLE)
 176
 177 /*
 178  * initialize a work item's function pointer
 179  */
 180 #define PREPARE_WORK(_work, _func)                                      \
 181         do {                                                            \
 182                 (_work)->func = (_func);                                \
 183         } while (0)
 184
 185 #define PREPARE_DELAYED_WORK(_work, _func)                              \
 186         PREPARE_WORK(&(_work)->work, (_func))
 187
 188 #ifdef CONFIG_DEBUG_OBJECTS_WORK
 189 extern void __init_work(struct work_struct *work, int onstack);
 190 extern void destroy_work_on_stack(struct work_struct *work);
 191 static inline unsigned int work_static(struct work_struct *work)
 192 {
 193         return *work_data_bits(work) & WORK_STRUCT_STATIC;
 194 }
 195 #else
 196 static inline void __init_work(struct work_struct *work, int onstack) { }
 197 static inline void destroy_work_on_stack(struct work_struct *work) { }
 198 static inline unsigned int work_static(struct work_struct *work) { return 0; }
 199 #endif
 200
 201 /*
 202  * initialize all of a work item in one go
 203  *
 204  * NOTE! No point in using "atomic_long_set()": using a direct
 205  * assignment of the work data initializer allows the compiler
 206  * to generate better code.
 207  */
 208 #ifdef CONFIG_LOCKDEP
 209 #define __INIT_WORK(_work, _func, _onstack)                             \
 210         do {                                                            \
 211                 static struct lock_class_key __key;                     \
 212                                                                         \
 213                 __init_work((_work), _onstack);                         \
 214                 (_work)->data = (atomic_long_t) WORK_DATA_INIT();       \
 215                 lockdep_init_map(&(_work)->lockdep_map, #_work, &__key, 0); \
 216                 INIT_LIST_HEAD(&(_work)->entry);                        \
 217                 PREPARE_WORK((_work), (_func));                         \
 218         } while (0)
 219 #else
 220 #define __INIT_WORK(_work, _func, _onstack)                             \
 221         do {                                                            \
 222                 __init_work((_work), _onstack);                         \
 223                 (_work)->data = (atomic_long_t) WORK_DATA_INIT();       \
 224                 INIT_LIST_HEAD(&(_work)->entry);                        \
 225                 PREPARE_WORK((_work), (_func));                         \
 226         } while (0)
 227 #endif
 228
 229 #define INIT_WORK(_work, _func)                                         \
 230         do {                                                            \
 231                 __INIT_WORK((_work), (_func), 0);                       \
 232         } while (0)
 233
 234 #define INIT_WORK_ONSTACK(_work, _func)                                 \
 235         do {                                                            \
 236                 __INIT_WORK((_work), (_func), 1);                       \
 237         } while (0)
 238
 239 #define __INIT_DELAYED_WORK(_work, _func, _tflags)                      \
 240         do {                                                            \
 241                 INIT_WORK(&(_work)->work, (_func));                     \
 242                 __setup_timer(&(_work)->timer, delayed_work_timer_fn,   \
 243                               (unsigned long)(_work),                   \
 244                               (_tflags) | TIMER_IRQSAFE);               \
 245         } while (0)
 246
 247 #define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags)              \
 248         do {                                                            \
 249                 INIT_WORK_ONSTACK(&(_work)->work, (_func));             \
 250                 __setup_timer_on_stack(&(_work)->timer,                 \
 251                                        delayed_work_timer_fn,           \
 252                                        (unsigned long)(_work),          \
 253                                        (_tflags) | TIMER_IRQSAFE);      \
 254         } while (0)
 255
 256 #define INIT_DELAYED_WORK(_work, _func)                                 \
 257         __INIT_DELAYED_WORK(_work, _func, 0)
 258
 259 #define INIT_DELAYED_WORK_ONSTACK(_work, _func)                         \
 260         __INIT_DELAYED_WORK_ONSTACK(_work, _func, 0)
 261
 262 #define INIT_DEFERRABLE_WORK(_work, _func)                              \
 263         __INIT_DELAYED_WORK(_work, _func, TIMER_DEFERRABLE)
 264
 265 #define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func)                      \
 266         __INIT_DELAYED_WORK_ONSTACK(_work, _func, TIMER_DEFERRABLE)
 267
 268 /**
 269  * work_pending - Find out whether a work item is currently pending
 270  * @work: The work item in question
 271  */
 272 #define work_pending(work) \
 273         test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
 274
 275 /**
 276  * delayed_work_pending - Find out whether a delayable work item is currently
 277  * pending
 278  * @work: The work item in question
 279  */
 280 #define delayed_work_pending(w) \
 281         work_pending(&(w)->work)
 282
 283 /**
 284  * work_clear_pending - for internal use only, mark a work item as not pending
 285  * @work: The work item in question
 286  */
 287 #define work_clear_pending(work) \
 288         clear_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
 289
 290 /*
 291  * Workqueue flags and constants.  For details, please refer to
 292  * Documentation/workqueue.txt.
 293  */
 294 enum {
 295         WQ_NON_REENTRANT        = 1 << 0, /* guarantee non-reentrance */
 296         WQ_UNBOUND              = 1 << 1, /* not bound to any cpu */
 297         WQ_FREEZABLE            = 1 << 2, /* freeze during suspend */
 298         WQ_MEM_RECLAIM          = 1 << 3, /* may be used for memory reclaim */
 299         WQ_HIGHPRI              = 1 << 4, /* high priority */
 300         WQ_CPU_INTENSIVE        = 1 << 5, /* cpu instensive workqueue */
 301         WQ_SYSFS                = 1 << 6, /* visible in sysfs, see wq_sysfs_register() */
 302
 303         __WQ_DRAINING           = 1 << 16, /* internal: workqueue is draining */
 304         __WQ_ORDERED            = 1 << 17, /* internal: workqueue is ordered */
 305
 306         WQ_MAX_ACTIVE           = 512,    /* I like 512, better ideas? */
 307         WQ_MAX_UNBOUND_PER_CPU  = 4,      /* 4 * #cpus for unbound wq */
 308         WQ_DFL_ACTIVE           = WQ_MAX_ACTIVE / 2,
 309 };
 310
 311 /* unbound wq's aren't per-cpu, scale max_active according to #cpus */
 312 #define WQ_UNBOUND_MAX_ACTIVE   \
 313         max_t(int, WQ_MAX_ACTIVE, num_possible_cpus() * WQ_MAX_UNBOUND_PER_CPU)
 314
 315 /*
 316  * System-wide workqueues which are always present.
 317  *
 318  * system_wq is the one used by schedule[_delayed]_work[_on]().
 319  * Multi-CPU multi-threaded.  There are users which expect relatively
 320  * short queue flush time.  Don't queue works which can run for too
 321  * long.
 322  *
 323  * system_long_wq is similar to system_wq but may host long running
 324  * works.  Queue flushing might take relatively long.
 325  *
 326  * system_unbound_wq is unbound workqueue.  Workers are not bound to
 327  * any specific CPU, not concurrency managed, and all queued works are
 328  * executed immediately as long as max_active limit is not reached and
 329  * resources are available.
 330  *
 331  * system_freezable_wq is equivalent to system_wq except that it's
 332  * freezable.
 333  */
 334 extern struct workqueue_struct *system_wq;
 335 extern struct workqueue_struct *system_long_wq;
 336 extern struct workqueue_struct *system_unbound_wq;
 337 extern struct workqueue_struct *system_freezable_wq;
 338
 339 static inline struct workqueue_struct * __deprecated __system_nrt_wq(void)
 340 {
 341         return system_wq;
 342 }
 343
 344 static inline struct workqueue_struct * __deprecated __system_nrt_freezable_wq(void)
 345 {
 346         return system_freezable_wq;
 347 }
 348
 349 /* equivlalent to system_wq and system_freezable_wq, deprecated */
 350 #define system_nrt_wq                   __system_nrt_wq()
 351 #define system_nrt_freezable_wq         __system_nrt_freezable_wq()
 352
 353 extern struct workqueue_struct *
 354 __alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active,
 355         struct lock_class_key *key, const char *lock_name, ...) __printf(1, 6);
 356
 357 /**
 358  * alloc_workqueue - allocate a workqueue
 359  * @fmt: printf format for the name of the workqueue
 360  * @flags: WQ_* flags
 361  * @max_active: max in-flight work items, 0 for default
 362  * @args: args for @fmt
 363  *
 364  * Allocate a workqueue with the specified parameters.  For detailed
 365  * information on WQ_* flags, please refer to Documentation/workqueue.txt.
 366  *
 367  * The __lock_name macro dance is to guarantee that single lock_class_key
 368  * doesn't end up with different namesm, which isn't allowed by lockdep.
 369  *
 370  * RETURNS:
 371  * Pointer to the allocated workqueue on success, %NULL on failure.
 372  */
 373 #ifdef CONFIG_LOCKDEP
 374 #define alloc_workqueue(fmt, flags, max_active, args...)                \
 375 ({                                                                      \
 376         static struct lock_class_key __key;                             \
 377         const char *__lock_name;                                        \
 378                                                                         \
 379         if (__builtin_constant_p(fmt))                                  \
 380                 __lock_name = (fmt);                                    \
 381         else                                                            \
 382                 __lock_name = #fmt;                                     \
 383                                                                         \
 384         __alloc_workqueue_key((fmt), (flags), (max_active),             \
 385                               &__key, __lock_name, ##args);             \
 386 })
 387 #else
 388 #define alloc_workqueue(fmt, flags, max_active, args...)                \
 389         __alloc_workqueue_key((fmt), (flags), (max_active),             \
 390                               NULL, NULL, ##args)
 391 #endif
 392
 393 /**
 394  * alloc_ordered_workqueue - allocate an ordered workqueue
 395  * @fmt: printf format for the name of the workqueue
 396  * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
 397  * @args: args for @fmt
 398  *
 399  * Allocate an ordered workqueue.  An ordered workqueue executes at
 400  * most one work item at any given time in the queued order.  They are
 401  * implemented as unbound workqueues with @max_active of one.
 402  *
 403  * RETURNS:
 404  * Pointer to the allocated workqueue on success, %NULL on failure.
 405  */
 406 #define alloc_ordered_workqueue(fmt, flags, args...)                    \
 407         alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | (flags), 1, ##args)
 408
 409 #define create_workqueue(name)                                          \
 410         alloc_workqueue((name), WQ_MEM_RECLAIM, 1)
 411 #define create_freezable_workqueue(name)                                \
 412         alloc_workqueue((name), WQ_FREEZABLE | WQ_UNBOUND | WQ_MEM_RECLAIM, 1)
 413 #define create_singlethread_workqueue(name)                             \
 414         alloc_workqueue((name), WQ_UNBOUND | WQ_MEM_RECLAIM, 1)
 415
 416 extern void destroy_workqueue(struct workqueue_struct *wq);
 417
 418 struct workqueue_attrs *alloc_workqueue_attrs(gfp_t gfp_mask);
 419 void free_workqueue_attrs(struct workqueue_attrs *attrs);
 420 int apply_workqueue_attrs(struct workqueue_struct *wq,
 421                           const struct workqueue_attrs *attrs);
 422
 423 extern bool queue_work_on(int cpu, struct workqueue_struct *wq,
 424                         struct work_struct *work);
 425 extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
 426                         struct delayed_work *work, unsigned long delay);
 427 extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
 428                         struct delayed_work *dwork, unsigned long delay);
 429
 430 extern void flush_workqueue(struct workqueue_struct *wq);
 431 extern void drain_workqueue(struct workqueue_struct *wq);
 432 extern void flush_scheduled_work(void);
 433
 434 extern int schedule_on_each_cpu(work_func_t func);
 435
 436 int execute_in_process_context(work_func_t fn, struct execute_work *);
 437
 438 extern bool flush_work(struct work_struct *work);
 439 extern bool cancel_work_sync(struct work_struct *work);
 440
 441 extern bool flush_delayed_work(struct delayed_work *dwork);
 442 extern bool cancel_delayed_work(struct delayed_work *dwork);
 443 extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
 444
 445 extern void workqueue_set_max_active(struct workqueue_struct *wq,
 446                                      int max_active);
 447 extern bool current_is_workqueue_rescuer(void);
 448 extern bool workqueue_congested(int cpu, struct workqueue_struct *wq);
 449 extern unsigned int work_busy(struct work_struct *work);
 450
 451 /**
 452  * queue_work - queue work on a workqueue
 453  * @wq: workqueue to use
 454  * @work: work to queue
 455  *
 456  * Returns %false if @work was already on a queue, %true otherwise.
 457  *
 458  * We queue the work to the CPU on which it was submitted, but if the CPU dies
 459  * it can be processed by another CPU.
 460  */
 461 static inline bool queue_work(struct workqueue_struct *wq,
 462                               struct work_struct *work)
 463 {
 464         return queue_work_on(WORK_CPU_UNBOUND, wq, work);
 465 }
 466
 467 /**
 468  * queue_delayed_work - queue work on a workqueue after delay
 469  * @wq: workqueue to use
 470  * @dwork: delayable work to queue
 471  * @delay: number of jiffies to wait before queueing
 472  *
 473  * Equivalent to queue_delayed_work_on() but tries to use the local CPU.
 474  */
 475 static inline bool queue_delayed_work(struct workqueue_struct *wq,
 476                                       struct delayed_work *dwork,
 477                                       unsigned long delay)
 478 {
 479         return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
 480 }
 481
 482 /**
 483  * mod_delayed_work - modify delay of or queue a delayed work
 484  * @wq: workqueue to use
 485  * @dwork: work to queue
 486  * @delay: number of jiffies to wait before queueing
 487  *
 488  * mod_delayed_work_on() on local CPU.
 489  */
 490 static inline bool mod_delayed_work(struct workqueue_struct *wq,
 491                                     struct delayed_work *dwork,
 492                                     unsigned long delay)
 493 {
 494         return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
 495 }
 496
 497 /**
 498  * schedule_work_on - put work task on a specific cpu
 499  * @cpu: cpu to put the work task on
 500  * @work: job to be done
 501  *
 502  * This puts a job on a specific cpu
 503  */
 504 static inline bool schedule_work_on(int cpu, struct work_struct *work)
 505 {
 506         return queue_work_on(cpu, system_wq, work);
 507 }
 508
 509 /**
 510  * schedule_work - put work task in global workqueue
 511  * @work: job to be done
 512  *
 513  * Returns %false if @work was already on the kernel-global workqueue and
 514  * %true otherwise.
 515  *
 516  * This puts a job in the kernel-global workqueue if it was not already
 517  * queued and leaves it in the same position on the kernel-global
 518  * workqueue otherwise.
 519  */
 520 static inline bool schedule_work(struct work_struct *work)
 521 {
 522         return queue_work(system_wq, work);
 523 }
 524
 525 /**
 526  * schedule_delayed_work_on - queue work in global workqueue on CPU after delay
 527  * @cpu: cpu to use
 528  * @dwork: job to be done
 529  * @delay: number of jiffies to wait
 530  *
 531  * After waiting for a given time this puts a job in the kernel-global
 532  * workqueue on the specified CPU.
 533  */
 534 static inline bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork,
 535                                             unsigned long delay)
 536 {
 537         return queue_delayed_work_on(cpu, system_wq, dwork, delay);
 538 }
 539
 540 /**
 541  * schedule_delayed_work - put work task in global workqueue after delay
 542  * @dwork: job to be done
 543  * @delay: number of jiffies to wait or 0 for immediate execution
 544  *
 545  * After waiting for a given time this puts a job in the kernel-global
 546  * workqueue.
 547  */
 548 static inline bool schedule_delayed_work(struct delayed_work *dwork,
 549                                          unsigned long delay)
 550 {
 551         return queue_delayed_work(system_wq, dwork, delay);
 552 }
 553
 554 /**
 555  * keventd_up - is workqueue initialized yet?
 556  */
 557 static inline bool keventd_up(void)
 558 {
 559         return system_wq != NULL;
 560 }
 561
 562 /*
 563  * Like above, but uses del_timer() instead of del_timer_sync(). This means,
 564  * if it returns 0 the timer function may be running and the queueing is in
 565  * progress.
 566  */
 567 static inline bool __deprecated __cancel_delayed_work(struct delayed_work *work)
 568 {
 569         bool ret;
 570
 571         ret = del_timer(&work->timer);
 572         if (ret)
 573                 work_clear_pending(&work->work);
 574         return ret;
 575 }
 576
 577 /* used to be different but now identical to flush_work(), deprecated */
 578 static inline bool __deprecated flush_work_sync(struct work_struct *work)
 579 {
 580         return flush_work(work);
 581 }
 582
 583 /* used to be different but now identical to flush_delayed_work(), deprecated */
 584 static inline bool __deprecated flush_delayed_work_sync(struct delayed_work *dwork)
 585 {
 586         return flush_delayed_work(dwork);
 587 }
 588
 589 #ifndef CONFIG_SMP
 590 static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
 591 {
 592         return fn(arg);
 593 }
 594 #else
 595 long work_on_cpu(int cpu, long (*fn)(void *), void *arg);
 596 #endif /* CONFIG_SMP */
 597
 598 #ifdef CONFIG_FREEZER
 599 extern void freeze_workqueues_begin(void);
 600 extern bool freeze_workqueues_busy(void);
 601 extern void thaw_workqueues(void);
 602 #endif /* CONFIG_FREEZER */
 603
 604 #ifdef CONFIG_SYSFS
 605 int workqueue_sysfs_register(struct workqueue_struct *wq);
 606 #else   /* CONFIG_SYSFS */
 607 static inline int workqueue_sysfs_register(struct workqueue_struct *wq)
 608 { return 0; }
 609 #endif  /* CONFIG_SYSFS */
 610
 611 #endif