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   = WORK_OFFQ_FLAG_BASE,
  75         WORK_OFFQ_CANCELING     = (1 << __WORK_OFFQ_CANCELING),
  76
  77         /*
  78          * When a work item is off queue, its high bits point to the last
  79          * pool it was on.  Cap at 31 bits and use the highest number to
  80          * indicate that no pool is associated.
  81          */
  82         WORK_OFFQ_FLAG_BITS     = 1,
  83         WORK_OFFQ_POOL_SHIFT    = WORK_OFFQ_FLAG_BASE + WORK_OFFQ_FLAG_BITS,
  84         WORK_OFFQ_LEFT          = BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT,
  85         WORK_OFFQ_POOL_BITS     = WORK_OFFQ_LEFT <= 31 ? WORK_OFFQ_LEFT : 31,
  86         WORK_OFFQ_POOL_NONE     = (1LU << WORK_OFFQ_POOL_BITS) - 1,
  87
  88         /* convenience constants */
  89         WORK_STRUCT_FLAG_MASK   = (1UL << WORK_STRUCT_FLAG_BITS) - 1,
  90         WORK_STRUCT_WQ_DATA_MASK = ~WORK_STRUCT_FLAG_MASK,
  91         WORK_STRUCT_NO_POOL     = (unsigned long)WORK_OFFQ_POOL_NONE << WORK_OFFQ_POOL_SHIFT,
  92
  93         /* bit mask for work_busy() return values */
  94         WORK_BUSY_PENDING       = 1 << 0,
  95         WORK_BUSY_RUNNING       = 1 << 1,
  96
  97         /* maximum string length for set_worker_desc() */
  98         WORKER_DESC_LEN         = 24,
  99 };
 100
 101 struct work_struct {
 102         atomic_long_t data;
 103         struct list_head entry;
 104         work_func_t func;
 105 #ifdef CONFIG_LOCKDEP
 106         struct lockdep_map lockdep_map;
 107 #endif
 108 };
 109
 110 #define WORK_DATA_INIT()        ATOMIC_LONG_INIT(WORK_STRUCT_NO_POOL)
 111 #define WORK_DATA_STATIC_INIT() \
 112         ATOMIC_LONG_INIT(WORK_STRUCT_NO_POOL | WORK_STRUCT_STATIC)
 113
 114 struct delayed_work {
 115         struct work_struct work;
 116         struct timer_list timer;
 117
 118         /* target workqueue and CPU ->timer uses to queue ->work */
 119         struct workqueue_struct *wq;
 120         int cpu;
 121 };
 122
 123 /*
 124  * A struct for workqueue attributes.  This can be used to change
 125  * attributes of an unbound workqueue.
 126  *
 127  * Unlike other fields, ->no_numa isn't a property of a worker_pool.  It
 128  * only modifies how apply_workqueue_attrs() select pools and thus doesn't
 129  * participate in pool hash calculations or equality comparisons.
 130  */
 131 struct workqueue_attrs {
 132         int                     nice;           /* nice level */
 133         cpumask_var_t           cpumask;        /* allowed CPUs */
 134         bool                    no_numa;        /* disable NUMA affinity */
 135 };
 136
 137 static inline struct delayed_work *to_delayed_work(struct work_struct *work)
 138 {
 139         return container_of(work, struct delayed_work, work);
 140 }
 141
 142 struct execute_work {
 143         struct work_struct work;
 144 };
 145
 146 #ifdef CONFIG_LOCKDEP
 147 /*
 148  * NB: because we have to copy the lockdep_map, setting _key
 149  * here is required, otherwise it could get initialised to the
 150  * copy of the lockdep_map!
 151  */
 152 #define __WORK_INIT_LOCKDEP_MAP(n, k) \
 153         .lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k),
 154 #else
 155 #define __WORK_INIT_LOCKDEP_MAP(n, k)
 156 #endif
 157
 158 #define __WORK_INITIALIZER(n, f) {                                      \
 159         .data = WORK_DATA_STATIC_INIT(),                                \
 160         .entry  = { &(n).entry, &(n).entry },                           \
 161         .func = (f),                                                    \
 162         __WORK_INIT_LOCKDEP_MAP(#n, &(n))                               \
 163         }
 164
 165 #define __DELAYED_WORK_INITIALIZER(n, f, tflags) {                      \
 166         .work = __WORK_INITIALIZER((n).work, (f)),                      \
 167         .timer = __TIMER_INITIALIZER(delayed_work_timer_fn,             \
 168                                      0, (unsigned long)&(n),            \
 169                                      (tflags) | TIMER_IRQSAFE),         \
 170         }
 171
 172 #define DECLARE_WORK(n, f)                                              \
 173         struct work_struct n = __WORK_INITIALIZER(n, f)
 174
 175 #define DECLARE_DELAYED_WORK(n, f)                                      \
 176         struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, 0)
 177
 178 #define DECLARE_DEFERRABLE_WORK(n, f)                                   \
 179         struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, TIMER_DEFERRABLE)
 180
 181 /*
 182  * initialize a work item's function pointer
 183  */
 184 #define PREPARE_WORK(_work, _func)                                      \
 185         do {                                                            \
 186                 (_work)->func = (_func);                                \
 187         } while (0)
 188
 189 #define PREPARE_DELAYED_WORK(_work, _func)                              \
 190         PREPARE_WORK(&(_work)->work, (_func))
 191
 192 #ifdef CONFIG_DEBUG_OBJECTS_WORK
 193 extern void __init_work(struct work_struct *work, int onstack);
 194 extern void destroy_work_on_stack(struct work_struct *work);
 195 static inline unsigned int work_static(struct work_struct *work)
 196 {
 197         return *work_data_bits(work) & WORK_STRUCT_STATIC;
 198 }
 199 #else
 200 static inline void __init_work(struct work_struct *work, int onstack) { }
 201 static inline void destroy_work_on_stack(struct work_struct *work) { }
 202 static inline unsigned int work_static(struct work_struct *work) { return 0; }
 203 #endif
 204
 205 /*
 206  * initialize all of a work item in one go
 207  *
 208  * NOTE! No point in using "atomic_long_set()": using a direct
 209  * assignment of the work data initializer allows the compiler
 210  * to generate better code.
 211  */
 212 #ifdef CONFIG_LOCKDEP
 213 #define __INIT_WORK(_work, _func, _onstack)                             \
 214         do {                                                            \
 215                 static struct lock_class_key __key;                     \
 216                                                                         \
 217                 __init_work((_work), _onstack);                         \
 218                 (_work)->data = (atomic_long_t) WORK_DATA_INIT();       \
 219                 lockdep_init_map(&(_work)->lockdep_map, #_work, &__key, 0); \
 220                 INIT_LIST_HEAD(&(_work)->entry);                        \
 221                 PREPARE_WORK((_work), (_func));                         \
 222         } while (0)
 223 #else
 224 #define __INIT_WORK(_work, _func, _onstack)                             \
 225         do {                                                            \
 226                 __init_work((_work), _onstack);                         \
 227                 (_work)->data = (atomic_long_t) WORK_DATA_INIT();       \
 228                 INIT_LIST_HEAD(&(_work)->entry);                        \
 229                 PREPARE_WORK((_work), (_func));                         \
 230         } while (0)
 231 #endif
 232
 233 #define INIT_WORK(_work, _func)                                         \
 234         do {                                                            \
 235                 __INIT_WORK((_work), (_func), 0);                       \
 236         } while (0)
 237
 238 #define INIT_WORK_ONSTACK(_work, _func)                                 \
 239         do {                                                            \
 240                 __INIT_WORK((_work), (_func), 1);                       \
 241         } while (0)
 242
 243 #define __INIT_DELAYED_WORK(_work, _func, _tflags)                      \
 244         do {                                                            \
 245                 INIT_WORK(&(_work)->work, (_func));                     \
 246                 __setup_timer(&(_work)->timer, delayed_work_timer_fn,   \
 247                               (unsigned long)(_work),                   \
 248                               (_tflags) | TIMER_IRQSAFE);               \
 249         } while (0)
 250
 251 #define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags)              \
 252         do {                                                            \
 253                 INIT_WORK_ONSTACK(&(_work)->work, (_func));             \
 254                 __setup_timer_on_stack(&(_work)->timer,                 \
 255                                        delayed_work_timer_fn,           \
 256                                        (unsigned long)(_work),          \
 257                                        (_tflags) | TIMER_IRQSAFE);      \
 258         } while (0)
 259
 260 #define INIT_DELAYED_WORK(_work, _func)                                 \
 261         __INIT_DELAYED_WORK(_work, _func, 0)
 262
 263 #define INIT_DELAYED_WORK_ONSTACK(_work, _func)                         \
 264         __INIT_DELAYED_WORK_ONSTACK(_work, _func, 0)
 265
 266 #define INIT_DEFERRABLE_WORK(_work, _func)                              \
 267         __INIT_DELAYED_WORK(_work, _func, TIMER_DEFERRABLE)
 268
 269 #define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func)                      \
 270         __INIT_DELAYED_WORK_ONSTACK(_work, _func, TIMER_DEFERRABLE)
 271
 272 /**
 273  * work_pending - Find out whether a work item is currently pending
 274  * @work: The work item in question
 275  */
 276 #define work_pending(work) \
 277         test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
 278
 279 /**
 280  * delayed_work_pending - Find out whether a delayable work item is currently
 281  * pending
 282  * @work: The work item in question
 283  */
 284 #define delayed_work_pending(w) \
 285         work_pending(&(w)->work)
 286
 287 /**
 288  * work_clear_pending - for internal use only, mark a work item as not pending
 289  * @work: The work item in question
 290  */
 291 #define work_clear_pending(work) \
 292         clear_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
 293
 294 /*
 295  * Workqueue flags and constants.  For details, please refer to
 296  * Documentation/workqueue.txt.
 297  */
 298 enum {
 299         WQ_NON_REENTRANT        = 1 << 0, /* guarantee non-reentrance */
 300         WQ_UNBOUND              = 1 << 1, /* not bound to any cpu */
 301         WQ_FREEZABLE            = 1 << 2, /* freeze during suspend */
 302         WQ_MEM_RECLAIM          = 1 << 3, /* may be used for memory reclaim */
 303         WQ_HIGHPRI              = 1 << 4, /* high priority */
 304         WQ_CPU_INTENSIVE        = 1 << 5, /* cpu instensive workqueue */
 305         WQ_SYSFS                = 1 << 6, /* visible in sysfs, see wq_sysfs_register() */
 306
 307         __WQ_DRAINING           = 1 << 16, /* internal: workqueue is draining */
 308         __WQ_ORDERED            = 1 << 17, /* internal: workqueue is ordered */
 309         __WQ_ORDERED_EXPLICIT   = 1 << 18, /* internal: alloc_ordered_workqueue() */
 310
 311         WQ_MAX_ACTIVE           = 512,    /* I like 512, better ideas? */
 312         WQ_MAX_UNBOUND_PER_CPU  = 4,      /* 4 * #cpus for unbound wq */
 313         WQ_DFL_ACTIVE           = WQ_MAX_ACTIVE / 2,
 314 };
 315
 316 /* unbound wq's aren't per-cpu, scale max_active according to #cpus */
 317 #define WQ_UNBOUND_MAX_ACTIVE   \
 318         max_t(int, WQ_MAX_ACTIVE, num_possible_cpus() * WQ_MAX_UNBOUND_PER_CPU)
 319
 320 /*
 321  * System-wide workqueues which are always present.
 322  *
 323  * system_wq is the one used by schedule[_delayed]_work[_on]().
 324  * Multi-CPU multi-threaded.  There are users which expect relatively
 325  * short queue flush time.  Don't queue works which can run for too
 326  * long.
 327  *
 328  * system_long_wq is similar to system_wq but may host long running
 329  * works.  Queue flushing might take relatively long.
 330  *
 331  * system_unbound_wq is unbound workqueue.  Workers are not bound to
 332  * any specific CPU, not concurrency managed, and all queued works are
 333  * executed immediately as long as max_active limit is not reached and
 334  * resources are available.
 335  *
 336  * system_freezable_wq is equivalent to system_wq except that it's
 337  * freezable.
 338  */
 339 extern struct workqueue_struct *system_wq;
 340 extern struct workqueue_struct *system_long_wq;
 341 extern struct workqueue_struct *system_unbound_wq;
 342 extern struct workqueue_struct *system_freezable_wq;
 343
 344 static inline struct workqueue_struct * __deprecated __system_nrt_wq(void)
 345 {
 346         return system_wq;
 347 }
 348
 349 static inline struct workqueue_struct * __deprecated __system_nrt_freezable_wq(void)
 350 {
 351         return system_freezable_wq;
 352 }
 353
 354 /* equivlalent to system_wq and system_freezable_wq, deprecated */
 355 #define system_nrt_wq                   __system_nrt_wq()
 356 #define system_nrt_freezable_wq         __system_nrt_freezable_wq()
 357
 358 extern struct workqueue_struct *
 359 __alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active,
 360         struct lock_class_key *key, const char *lock_name, ...) __printf(1, 6);
 361
 362 /**
 363  * alloc_workqueue - allocate a workqueue
 364  * @fmt: printf format for the name of the workqueue
 365  * @flags: WQ_* flags
 366  * @max_active: max in-flight work items, 0 for default
 367  * @args: args for @fmt
 368  *
 369  * Allocate a workqueue with the specified parameters.  For detailed
 370  * information on WQ_* flags, please refer to Documentation/workqueue.txt.
 371  *
 372  * The __lock_name macro dance is to guarantee that single lock_class_key
 373  * doesn't end up with different namesm, which isn't allowed by lockdep.
 374  *
 375  * RETURNS:
 376  * Pointer to the allocated workqueue on success, %NULL on failure.
 377  */
 378 #ifdef CONFIG_LOCKDEP
 379 #define alloc_workqueue(fmt, flags, max_active, args...)                \
 380 ({                                                                      \
 381         static struct lock_class_key __key;                             \
 382         const char *__lock_name;                                        \
 383                                                                         \
 384         if (__builtin_constant_p(fmt))                                  \
 385                 __lock_name = (fmt);                                    \
 386         else                                                            \
 387                 __lock_name = #fmt;                                     \
 388                                                                         \
 389         __alloc_workqueue_key((fmt), (flags), (max_active),             \
 390                               &__key, __lock_name, ##args);             \
 391 })
 392 #else
 393 #define alloc_workqueue(fmt, flags, max_active, args...)                \
 394         __alloc_workqueue_key((fmt), (flags), (max_active),             \
 395                               NULL, NULL, ##args)
 396 #endif
 397
 398 /**
 399  * alloc_ordered_workqueue - allocate an ordered workqueue
 400  * @fmt: printf format for the name of the workqueue
 401  * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
 402  * @args: args for @fmt
 403  *
 404  * Allocate an ordered workqueue.  An ordered workqueue executes at
 405  * most one work item at any given time in the queued order.  They are
 406  * implemented as unbound workqueues with @max_active of one.
 407  *
 408  * RETURNS:
 409  * Pointer to the allocated workqueue on success, %NULL on failure.
 410  */
 411 #define alloc_ordered_workqueue(fmt, flags, args...)                    \
 412         alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED |                \
 413                         __WQ_ORDERED_EXPLICIT | (flags), 1, ##args)
 414
 415 #define create_workqueue(name)                                          \
 416         alloc_workqueue((name), WQ_MEM_RECLAIM, 1)
 417 #define create_freezable_workqueue(name)                                \
 418         alloc_workqueue((name), WQ_FREEZABLE | WQ_UNBOUND | WQ_MEM_RECLAIM, 1)
 419 #define create_singlethread_workqueue(name)                             \
 420         alloc_ordered_workqueue("%s", WQ_MEM_RECLAIM, name)
 421
 422 extern void destroy_workqueue(struct workqueue_struct *wq);
 423
 424 struct workqueue_attrs *alloc_workqueue_attrs(gfp_t gfp_mask);
 425 void free_workqueue_attrs(struct workqueue_attrs *attrs);
 426 int apply_workqueue_attrs(struct workqueue_struct *wq,
 427                           const struct workqueue_attrs *attrs);
 428
 429 extern bool queue_work_on(int cpu, struct workqueue_struct *wq,
 430                         struct work_struct *work);
 431 extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
 432                         struct delayed_work *work, unsigned long delay);
 433 extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
 434                         struct delayed_work *dwork, unsigned long delay);
 435
 436 extern void flush_workqueue(struct workqueue_struct *wq);
 437 extern void drain_workqueue(struct workqueue_struct *wq);
 438 extern void flush_scheduled_work(void);
 439
 440 extern int schedule_on_each_cpu(work_func_t func);
 441
 442 int execute_in_process_context(work_func_t fn, struct execute_work *);
 443
 444 extern bool flush_work(struct work_struct *work);
 445 extern bool cancel_work_sync(struct work_struct *work);
 446
 447 extern bool flush_delayed_work(struct delayed_work *dwork);
 448 extern bool cancel_delayed_work(struct delayed_work *dwork);
 449 extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
 450
 451 extern void workqueue_set_max_active(struct workqueue_struct *wq,
 452                                      int max_active);
 453 extern bool current_is_workqueue_rescuer(void);
 454 extern bool workqueue_congested(int cpu, struct workqueue_struct *wq);
 455 extern unsigned int work_busy(struct work_struct *work);
 456 extern __printf(1, 2) void set_worker_desc(const char *fmt, ...);
 457 extern void print_worker_info(const char *log_lvl, struct task_struct *task);
 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  */
 469 static 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  */
 483 static 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  */
 498 static 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  */
 512 static 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  */
 528 static 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  */
 542 static 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  */
 556 static 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  */
 565 static inline bool keventd_up(void)
 566 {
 567         return system_wq != NULL;
 568 }
 569
 570 /*
 571  * Like above, but uses del_timer() instead of del_timer_sync(). This means,
 572  * if it returns 0 the timer function may be running and the queueing is in
 573  * progress.
 574  */
 575 static inline bool __deprecated __cancel_delayed_work(struct delayed_work *work)
 576 {
 577         bool ret;
 578
 579         ret = del_timer(&work->timer);
 580         if (ret)
 581                 work_clear_pending(&work->work);
 582         return ret;
 583 }
 584
 585 /* used to be different but now identical to flush_work(), deprecated */
 586 static inline bool __deprecated flush_work_sync(struct work_struct *work)
 587 {
 588         return flush_work(work);
 589 }
 590
 591 /* used to be different but now identical to flush_delayed_work(), deprecated */
 592 static inline bool __deprecated flush_delayed_work_sync(struct delayed_work *dwork)
 593 {
 594         return flush_delayed_work(dwork);
 595 }
 596
 597 #ifndef CONFIG_SMP
 598 static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
 599 {
 600         return fn(arg);
 601 }
 602 #else
 603 long work_on_cpu(int cpu, long (*fn)(void *), void *arg);
 604 #endif /* CONFIG_SMP */
 605
 606 #ifdef CONFIG_FREEZER
 607 extern void freeze_workqueues_begin(void);
 608 extern bool freeze_workqueues_busy(void);
 609 extern void thaw_workqueues(void);
 610 #endif /* CONFIG_FREEZER */
 611
 612 #ifdef CONFIG_SYSFS
 613 int workqueue_sysfs_register(struct workqueue_struct *wq);
 614 #else   /* CONFIG_SYSFS */
 615 static inline int workqueue_sysfs_register(struct workqueue_struct *wq)
 616 { return 0; }
 617 #endif  /* CONFIG_SYSFS */
 618
 619 #endif