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         /* 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     = (1 << WORK_OFFQ_FLAG_BASE),
  74
  75         /*
  76          * When a work item is off queue, its high bits point to the last
  77          * pool it was on.  Cap at 31 bits and use the highest number to
  78          * indicate that no pool is associated.
  79          */
  80         WORK_OFFQ_FLAG_BITS     = 1,
  81         WORK_OFFQ_POOL_SHIFT    = WORK_OFFQ_FLAG_BASE + WORK_OFFQ_FLAG_BITS,
  82         WORK_OFFQ_LEFT          = BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT,
  83         WORK_OFFQ_POOL_BITS     = WORK_OFFQ_LEFT <= 31 ? WORK_OFFQ_LEFT : 31,
  84         WORK_OFFQ_POOL_NONE     = (1LU << WORK_OFFQ_POOL_BITS) - 1,
  85
  86         /* convenience constants */
  87         WORK_STRUCT_FLAG_MASK   = (1UL << WORK_STRUCT_FLAG_BITS) - 1,
  88         WORK_STRUCT_WQ_DATA_MASK = ~WORK_STRUCT_FLAG_MASK,
  89         WORK_STRUCT_NO_POOL     = (unsigned long)WORK_OFFQ_POOL_NONE << WORK_OFFQ_POOL_SHIFT,
  90
  91         /* bit mask for work_busy() return values */
  92         WORK_BUSY_PENDING       = 1 << 0,
  93         WORK_BUSY_RUNNING       = 1 << 1,
  94
  95         /* maximum string length for set_worker_desc() */
  96         WORKER_DESC_LEN         = 24,
  97 };
  98
  99 struct work_struct {
 100         atomic_long_t data;
 101         struct list_head entry;
 102         work_func_t func;
 103 #ifdef CONFIG_LOCKDEP
 104         struct lockdep_map lockdep_map;
 105 #endif
 106 };
 107
 108 #define WORK_DATA_INIT()        ATOMIC_LONG_INIT(WORK_STRUCT_NO_POOL)
 109 #define WORK_DATA_STATIC_INIT() \
 110         ATOMIC_LONG_INIT(WORK_STRUCT_NO_POOL | WORK_STRUCT_STATIC)
 111
 112 struct delayed_work {
 113         struct work_struct work;
 114         struct timer_list timer;
 115
 116         /* target workqueue and CPU ->timer uses to queue ->work */
 117         struct workqueue_struct *wq;
 118         int cpu;
 119 };
 120
 121 /*
 122  * A struct for workqueue attributes.  This can be used to change
 123  * attributes of an unbound workqueue.
 124  *
 125  * Unlike other fields, ->no_numa isn't a property of a worker_pool.  It
 126  * only modifies how apply_workqueue_attrs() select pools and thus doesn't
 127  * participate in pool hash calculations or equality comparisons.
 128  */
 129 struct workqueue_attrs {
 130         int                     nice;           /* nice level */
 131         cpumask_var_t           cpumask;        /* allowed CPUs */
 132         bool                    no_numa;        /* disable NUMA affinity */
 133 };
 134
 135 static inline struct delayed_work *to_delayed_work(struct work_struct *work)
 136 {
 137         return container_of(work, struct delayed_work, work);
 138 }
 139
 140 struct execute_work {
 141         struct work_struct work;
 142 };
 143
 144 #ifdef CONFIG_LOCKDEP
 145 /*
 146  * NB: because we have to copy the lockdep_map, setting _key
 147  * here is required, otherwise it could get initialised to the
 148  * copy of the lockdep_map!
 149  */
 150 #define __WORK_INIT_LOCKDEP_MAP(n, k) \
 151         .lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k),
 152 #else
 153 #define __WORK_INIT_LOCKDEP_MAP(n, k)
 154 #endif
 155
 156 #define __WORK_INITIALIZER(n, f) {                                      \
 157         .data = WORK_DATA_STATIC_INIT(),                                \
 158         .entry  = { &(n).entry, &(n).entry },                           \
 159         .func = (f),                                                    \
 160         __WORK_INIT_LOCKDEP_MAP(#n, &(n))                               \
 161         }
 162
 163 #define __DELAYED_WORK_INITIALIZER(n, f, tflags) {                      \
 164         .work = __WORK_INITIALIZER((n).work, (f)),                      \
 165         .timer = __TIMER_INITIALIZER(delayed_work_timer_fn,             \
 166                                      0, (unsigned long)&(n),            \
 167                                      (tflags) | TIMER_IRQSAFE),         \
 168         }
 169
 170 #define DECLARE_WORK(n, f)                                              \
 171         struct work_struct n = __WORK_INITIALIZER(n, f)
 172
 173 #define DECLARE_DELAYED_WORK(n, f)                                      \
 174         struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, 0)
 175
 176 #define DECLARE_DEFERRABLE_WORK(n, f)                                   \
 177         struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, TIMER_DEFERRABLE)
 178
 179 #ifdef CONFIG_DEBUG_OBJECTS_WORK
 180 extern void __init_work(struct work_struct *work, int onstack);
 181 extern void destroy_work_on_stack(struct work_struct *work);
 182 extern void destroy_delayed_work_on_stack(struct delayed_work *work);
 183 static inline unsigned int work_static(struct work_struct *work)
 184 {
 185         return *work_data_bits(work) & WORK_STRUCT_STATIC;
 186 }
 187 #else
 188 static inline void __init_work(struct work_struct *work, int onstack) { }
 189 static inline void destroy_work_on_stack(struct work_struct *work) { }
 190 static inline void destroy_delayed_work_on_stack(struct delayed_work *work) { }
 191 static inline unsigned int work_static(struct work_struct *work) { return 0; }
 192 #endif
 193
 194 /*
 195  * initialize all of a work item in one go
 196  *
 197  * NOTE! No point in using "atomic_long_set()": using a direct
 198  * assignment of the work data initializer allows the compiler
 199  * to generate better code.
 200  */
 201 #ifdef CONFIG_LOCKDEP
 202 #define __INIT_WORK(_work, _func, _onstack)                             \
 203         do {                                                            \
 204                 static struct lock_class_key __key;                     \
 205                                                                         \
 206                 __init_work((_work), _onstack);                         \
 207                 (_work)->data = (atomic_long_t) WORK_DATA_INIT();       \
 208                 lockdep_init_map(&(_work)->lockdep_map, #_work, &__key, 0); \
 209                 INIT_LIST_HEAD(&(_work)->entry);                        \
 210                 (_work)->func = (_func);                                \
 211         } while (0)
 212 #else
 213 #define __INIT_WORK(_work, _func, _onstack)                             \
 214         do {                                                            \
 215                 __init_work((_work), _onstack);                         \
 216                 (_work)->data = (atomic_long_t) WORK_DATA_INIT();       \
 217                 INIT_LIST_HEAD(&(_work)->entry);                        \
 218                 (_work)->func = (_func);                                \
 219         } while (0)
 220 #endif
 221
 222 #define INIT_WORK(_work, _func)                                         \
 223         do {                                                            \
 224                 __INIT_WORK((_work), (_func), 0);                       \
 225         } while (0)
 226
 227 #define INIT_WORK_ONSTACK(_work, _func)                                 \
 228         do {                                                            \
 229                 __INIT_WORK((_work), (_func), 1);                       \
 230         } while (0)
 231
 232 #define __INIT_DELAYED_WORK(_work, _func, _tflags)                      \
 233         do {                                                            \
 234                 INIT_WORK(&(_work)->work, (_func));                     \
 235                 __setup_timer(&(_work)->timer, delayed_work_timer_fn,   \
 236                               (unsigned long)(_work),                   \
 237                               (_tflags) | TIMER_IRQSAFE);               \
 238         } while (0)
 239
 240 #define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags)              \
 241         do {                                                            \
 242                 INIT_WORK_ONSTACK(&(_work)->work, (_func));             \
 243                 __setup_timer_on_stack(&(_work)->timer,                 \
 244                                        delayed_work_timer_fn,           \
 245                                        (unsigned long)(_work),          \
 246                                        (_tflags) | TIMER_IRQSAFE);      \
 247         } while (0)
 248
 249 #define INIT_DELAYED_WORK(_work, _func)                                 \
 250         __INIT_DELAYED_WORK(_work, _func, 0)
 251
 252 #define INIT_DELAYED_WORK_ONSTACK(_work, _func)                         \
 253         __INIT_DELAYED_WORK_ONSTACK(_work, _func, 0)
 254
 255 #define INIT_DEFERRABLE_WORK(_work, _func)                              \
 256         __INIT_DELAYED_WORK(_work, _func, TIMER_DEFERRABLE)
 257
 258 #define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func)                      \
 259         __INIT_DELAYED_WORK_ONSTACK(_work, _func, TIMER_DEFERRABLE)
 260
 261 /**
 262  * work_pending - Find out whether a work item is currently pending
 263  * @work: The work item in question
 264  */
 265 #define work_pending(work) \
 266         test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
 267
 268 /**
 269  * delayed_work_pending - Find out whether a delayable work item is currently
 270  * pending
 271  * @work: The work item in question
 272  */
 273 #define delayed_work_pending(w) \
 274         work_pending(&(w)->work)
 275
 276 /*
 277  * Workqueue flags and constants.  For details, please refer to
 278  * Documentation/workqueue.txt.
 279  */
 280 enum {
 281         WQ_UNBOUND              = 1 << 1, /* not bound to any cpu */
 282         WQ_FREEZABLE            = 1 << 2, /* freeze during suspend */
 283         WQ_MEM_RECLAIM          = 1 << 3, /* may be used for memory reclaim */
 284         WQ_HIGHPRI              = 1 << 4, /* high priority */
 285         WQ_CPU_INTENSIVE        = 1 << 5, /* cpu intensive workqueue */
 286         WQ_SYSFS                = 1 << 6, /* visible in sysfs, see wq_sysfs_register() */
 287
 288         /*
 289          * Per-cpu workqueues are generally preferred because they tend to
 290          * show better performance thanks to cache locality.  Per-cpu
 291          * workqueues exclude the scheduler from choosing the CPU to
 292          * execute the worker threads, which has an unfortunate side effect
 293          * of increasing power consumption.
 294          *
 295          * The scheduler considers a CPU idle if it doesn't have any task
 296          * to execute and tries to keep idle cores idle to conserve power;
 297          * however, for example, a per-cpu work item scheduled from an
 298          * interrupt handler on an idle CPU will force the scheduler to
 299          * excute the work item on that CPU breaking the idleness, which in
 300          * turn may lead to more scheduling choices which are sub-optimal
 301          * in terms of power consumption.
 302          *
 303          * Workqueues marked with WQ_POWER_EFFICIENT are per-cpu by default
 304          * but become unbound if workqueue.power_efficient kernel param is
 305          * specified.  Per-cpu workqueues which are identified to
 306          * contribute significantly to power-consumption are identified and
 307          * marked with this flag and enabling the power_efficient mode
 308          * leads to noticeable power saving at the cost of small
 309          * performance disadvantage.
 310          *
 311          * http://thread.gmane.org/gmane.linux.kernel/1480396
 312          */
 313         WQ_POWER_EFFICIENT      = 1 << 7,
 314
 315         __WQ_DRAINING           = 1 << 16, /* internal: workqueue is draining */
 316         __WQ_ORDERED            = 1 << 17, /* internal: workqueue is ordered */
 317
 318         WQ_MAX_ACTIVE           = 512,    /* I like 512, better ideas? */
 319         WQ_MAX_UNBOUND_PER_CPU  = 4,      /* 4 * #cpus for unbound wq */
 320         WQ_DFL_ACTIVE           = WQ_MAX_ACTIVE / 2,
 321 };
 322
 323 /* unbound wq's aren't per-cpu, scale max_active according to #cpus */
 324 #define WQ_UNBOUND_MAX_ACTIVE   \
 325         max_t(int, WQ_MAX_ACTIVE, num_possible_cpus() * WQ_MAX_UNBOUND_PER_CPU)
 326
 327 /*
 328  * System-wide workqueues which are always present.
 329  *
 330  * system_wq is the one used by schedule[_delayed]_work[_on]().
 331  * Multi-CPU multi-threaded.  There are users which expect relatively
 332  * short queue flush time.  Don't queue works which can run for too
 333  * long.
 334  *
 335  * system_highpri_wq is similar to system_wq but for work items which
 336  * require WQ_HIGHPRI.
 337  *
 338  * system_long_wq is similar to system_wq but may host long running
 339  * works.  Queue flushing might take relatively long.
 340  *
 341  * system_unbound_wq is unbound workqueue.  Workers are not bound to
 342  * any specific CPU, not concurrency managed, and all queued works are
 343  * executed immediately as long as max_active limit is not reached and
 344  * resources are available.
 345  *
 346  * system_freezable_wq is equivalent to system_wq except that it's
 347  * freezable.
 348  *
 349  * *_power_efficient_wq are inclined towards saving power and converted
 350  * into WQ_UNBOUND variants if 'wq_power_efficient' is enabled; otherwise,
 351  * they are same as their non-power-efficient counterparts - e.g.
 352  * system_power_efficient_wq is identical to system_wq if
 353  * 'wq_power_efficient' is disabled.  See WQ_POWER_EFFICIENT for more info.
 354  */
 355 extern struct workqueue_struct *system_wq;
 356 extern struct workqueue_struct *system_highpri_wq;
 357 extern struct workqueue_struct *system_long_wq;
 358 extern struct workqueue_struct *system_unbound_wq;
 359 extern struct workqueue_struct *system_freezable_wq;
 360 extern struct workqueue_struct *system_power_efficient_wq;
 361 extern struct workqueue_struct *system_freezable_power_efficient_wq;
 362
 363 extern struct workqueue_struct *
 364 __alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active,
 365         struct lock_class_key *key, const char *lock_name, ...) __printf(1, 6);
 366
 367 /**
 368  * alloc_workqueue - allocate a workqueue
 369  * @fmt: printf format for the name of the workqueue
 370  * @flags: WQ_* flags
 371  * @max_active: max in-flight work items, 0 for default
 372  * @args: args for @fmt
 373  *
 374  * Allocate a workqueue with the specified parameters.  For detailed
 375  * information on WQ_* flags, please refer to Documentation/workqueue.txt.
 376  *
 377  * The __lock_name macro dance is to guarantee that single lock_class_key
 378  * doesn't end up with different namesm, which isn't allowed by lockdep.
 379  *
 380  * RETURNS:
 381  * Pointer to the allocated workqueue on success, %NULL on failure.
 382  */
 383 #ifdef CONFIG_LOCKDEP
 384 #define alloc_workqueue(fmt, flags, max_active, args...)                \
 385 ({                                                                      \
 386         static struct lock_class_key __key;                             \
 387         const char *__lock_name;                                        \
 388                                                                         \
 389         __lock_name = #fmt#args;                                        \
 390                                                                         \
 391         __alloc_workqueue_key((fmt), (flags), (max_active),             \
 392                               &__key, __lock_name, ##args);             \
 393 })
 394 #else
 395 #define alloc_workqueue(fmt, flags, max_active, args...)                \
 396         __alloc_workqueue_key((fmt), (flags), (max_active),             \
 397                               NULL, NULL, ##args)
 398 #endif
 399
 400 /**
 401  * alloc_ordered_workqueue - allocate an ordered workqueue
 402  * @fmt: printf format for the name of the workqueue
 403  * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
 404  * @args: args for @fmt
 405  *
 406  * Allocate an ordered workqueue.  An ordered workqueue executes at
 407  * most one work item at any given time in the queued order.  They are
 408  * implemented as unbound workqueues with @max_active of one.
 409  *
 410  * RETURNS:
 411  * Pointer to the allocated workqueue on success, %NULL on failure.
 412  */
 413 #define alloc_ordered_workqueue(fmt, flags, args...)                    \
 414         alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | (flags), 1, ##args)
 415
 416 #define create_workqueue(name)                                          \
 417         alloc_workqueue("%s", WQ_MEM_RECLAIM, 1, (name))
 418 #define create_freezable_workqueue(name)                                \
 419         alloc_workqueue("%s", WQ_FREEZABLE | WQ_UNBOUND | WQ_MEM_RECLAIM, \
 420                         1, (name))
 421 #define create_singlethread_workqueue(name)                             \
 422         alloc_ordered_workqueue("%s", WQ_MEM_RECLAIM, name)
 423
 424 extern void destroy_workqueue(struct workqueue_struct *wq);
 425
 426 struct workqueue_attrs *alloc_workqueue_attrs(gfp_t gfp_mask);
 427 void free_workqueue_attrs(struct workqueue_attrs *attrs);
 428 int apply_workqueue_attrs(struct workqueue_struct *wq,
 429                           const struct workqueue_attrs *attrs);
 430
 431 extern bool queue_work_on(int cpu, struct workqueue_struct *wq,
 432                         struct work_struct *work);
 433 extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
 434                         struct delayed_work *work, unsigned long delay);
 435 extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
 436                         struct delayed_work *dwork, unsigned long delay);
 437
 438 extern void flush_workqueue(struct workqueue_struct *wq);
 439 extern void drain_workqueue(struct workqueue_struct *wq);
 440 extern void flush_scheduled_work(void);
 441
 442 extern int schedule_on_each_cpu(work_func_t func);
 443
 444 int execute_in_process_context(work_func_t fn, struct execute_work *);
 445
 446 extern bool flush_work(struct work_struct *work);
 447 extern bool cancel_work_sync(struct work_struct *work);
 448
 449 extern bool flush_delayed_work(struct delayed_work *dwork);
 450 extern bool cancel_delayed_work(struct delayed_work *dwork);
 451 extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
 452
 453 extern void workqueue_set_max_active(struct workqueue_struct *wq,
 454                                      int max_active);
 455 extern bool current_is_workqueue_rescuer(void);
 456 extern bool workqueue_congested(int cpu, struct workqueue_struct *wq);
 457 extern unsigned int work_busy(struct work_struct *work);
 458 extern __printf(1, 2) void set_worker_desc(const char *fmt, ...);
 459 extern void print_worker_info(const char *log_lvl, struct task_struct *task);
 460
 461 /**
 462  * queue_work - queue work on a workqueue
 463  * @wq: workqueue to use
 464  * @work: work to queue
 465  *
 466  * Returns %false if @work was already on a queue, %true otherwise.
 467  *
 468  * We queue the work to the CPU on which it was submitted, but if the CPU dies
 469  * it can be processed by another CPU.
 470  */
 471 static inline bool queue_work(struct workqueue_struct *wq,
 472                               struct work_struct *work)
 473 {
 474         return queue_work_on(WORK_CPU_UNBOUND, wq, work);
 475 }
 476
 477 /**
 478  * queue_delayed_work - queue work on a workqueue after delay
 479  * @wq: workqueue to use
 480  * @dwork: delayable work to queue
 481  * @delay: number of jiffies to wait before queueing
 482  *
 483  * Equivalent to queue_delayed_work_on() but tries to use the local CPU.
 484  */
 485 static inline bool queue_delayed_work(struct workqueue_struct *wq,
 486                                       struct delayed_work *dwork,
 487                                       unsigned long delay)
 488 {
 489         return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
 490 }
 491
 492 /**
 493  * mod_delayed_work - modify delay of or queue a delayed work
 494  * @wq: workqueue to use
 495  * @dwork: work to queue
 496  * @delay: number of jiffies to wait before queueing
 497  *
 498  * mod_delayed_work_on() on local CPU.
 499  */
 500 static inline bool mod_delayed_work(struct workqueue_struct *wq,
 501                                     struct delayed_work *dwork,
 502                                     unsigned long delay)
 503 {
 504         return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
 505 }
 506
 507 /**
 508  * schedule_work_on - put work task on a specific cpu
 509  * @cpu: cpu to put the work task on
 510  * @work: job to be done
 511  *
 512  * This puts a job on a specific cpu
 513  */
 514 static inline bool schedule_work_on(int cpu, struct work_struct *work)
 515 {
 516         return queue_work_on(cpu, system_wq, work);
 517 }
 518
 519 /**
 520  * schedule_work - put work task in global workqueue
 521  * @work: job to be done
 522  *
 523  * Returns %false if @work was already on the kernel-global workqueue and
 524  * %true otherwise.
 525  *
 526  * This puts a job in the kernel-global workqueue if it was not already
 527  * queued and leaves it in the same position on the kernel-global
 528  * workqueue otherwise.
 529  */
 530 static inline bool schedule_work(struct work_struct *work)
 531 {
 532         return queue_work(system_wq, work);
 533 }
 534
 535 /**
 536  * schedule_delayed_work_on - queue work in global workqueue on CPU after delay
 537  * @cpu: cpu to use
 538  * @dwork: job to be done
 539  * @delay: number of jiffies to wait
 540  *
 541  * After waiting for a given time this puts a job in the kernel-global
 542  * workqueue on the specified CPU.
 543  */
 544 static inline bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork,
 545                                             unsigned long delay)
 546 {
 547         return queue_delayed_work_on(cpu, system_wq, dwork, delay);
 548 }
 549
 550 /**
 551  * schedule_delayed_work - put work task in global workqueue after delay
 552  * @dwork: job to be done
 553  * @delay: number of jiffies to wait or 0 for immediate execution
 554  *
 555  * After waiting for a given time this puts a job in the kernel-global
 556  * workqueue.
 557  */
 558 static inline bool schedule_delayed_work(struct delayed_work *dwork,
 559                                          unsigned long delay)
 560 {
 561         return queue_delayed_work(system_wq, dwork, delay);
 562 }
 563
 564 /**
 565  * keventd_up - is workqueue initialized yet?
 566  */
 567 static inline bool keventd_up(void)
 568 {
 569         return system_wq != NULL;
 570 }
 571
 572 #ifndef CONFIG_SMP
 573 static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
 574 {
 575         return fn(arg);
 576 }
 577 #else
 578 long work_on_cpu(int cpu, long (*fn)(void *), void *arg);
 579 #endif /* CONFIG_SMP */
 580
 581 #ifdef CONFIG_FREEZER
 582 extern void freeze_workqueues_begin(void);
 583 extern bool freeze_workqueues_busy(void);
 584 extern void thaw_workqueues(void);
 585 #endif /* CONFIG_FREEZER */
 586
 587 #ifdef CONFIG_SYSFS
 588 int workqueue_sysfs_register(struct workqueue_struct *wq);
 589 #else   /* CONFIG_SYSFS */
 590 static inline int workqueue_sysfs_register(struct workqueue_struct *wq)
 591 { return 0; }
 592 #endif  /* CONFIG_SYSFS */
 593
 594 #endif