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         /* maximum string length for set_worker_desc() */
  97         WORKER_DESC_LEN         = 24,
  98 };
  99
 100 struct work_struct {
 101         atomic_long_t data;
 102         struct list_head entry;
 103         work_func_t func;
 104 #ifdef CONFIG_LOCKDEP
 105         struct lockdep_map lockdep_map;
 106 #endif
 107 };
 108
 109 #define WORK_DATA_INIT()        ATOMIC_LONG_INIT(WORK_STRUCT_NO_POOL)
 110 #define WORK_DATA_STATIC_INIT() \
 111         ATOMIC_LONG_INIT(WORK_STRUCT_NO_POOL | WORK_STRUCT_STATIC)
 112
 113 struct delayed_work {
 114         struct work_struct work;
 115         struct timer_list timer;
 116
 117         /* target workqueue and CPU ->timer uses to queue ->work */
 118         struct workqueue_struct *wq;
 119         int cpu;
 120 };
 121
 122 /*
 123  * A struct for workqueue attributes.  This can be used to change
 124  * attributes of an unbound workqueue.
 125  *
 126  * Unlike other fields, ->no_numa isn't a property of a worker_pool.  It
 127  * only modifies how apply_workqueue_attrs() select pools and thus doesn't
 128  * participate in pool hash calculations or equality comparisons.
 129  */
 130 struct workqueue_attrs {
 131         int                     nice;           /* nice level */
 132         cpumask_var_t           cpumask;        /* allowed CPUs */
 133         bool                    no_numa;        /* disable NUMA affinity */
 134 };
 135
 136 static inline struct delayed_work *to_delayed_work(struct work_struct *work)
 137 {
 138         return container_of(work, struct delayed_work, work);
 139 }
 140
 141 struct execute_work {
 142         struct work_struct work;
 143 };
 144
 145 #ifdef CONFIG_LOCKDEP
 146 /*
 147  * NB: because we have to copy the lockdep_map, setting _key
 148  * here is required, otherwise it could get initialised to the
 149  * copy of the lockdep_map!
 150  */
 151 #define __WORK_INIT_LOCKDEP_MAP(n, k) \
 152         .lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k),
 153 #else
 154 #define __WORK_INIT_LOCKDEP_MAP(n, k)
 155 #endif
 156
 157 #define __WORK_INITIALIZER(n, f) {                                      \
 158         .data = WORK_DATA_STATIC_INIT(),                                \
 159         .entry  = { &(n).entry, &(n).entry },                           \
 160         .func = (f),                                                    \
 161         __WORK_INIT_LOCKDEP_MAP(#n, &(n))                               \
 162         }
 163
 164 #define __DELAYED_WORK_INITIALIZER(n, f, tflags) {                      \
 165         .work = __WORK_INITIALIZER((n).work, (f)),                      \
 166         .timer = __TIMER_INITIALIZER(delayed_work_timer_fn,             \
 167                                      0, (unsigned long)&(n),            \
 168                                      (tflags) | TIMER_IRQSAFE),         \
 169         }
 170
 171 #define DECLARE_WORK(n, f)                                              \
 172         struct work_struct n = __WORK_INITIALIZER(n, f)
 173
 174 #define DECLARE_DELAYED_WORK(n, f)                                      \
 175         struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, 0)
 176
 177 #define DECLARE_DEFERRABLE_WORK(n, f)                                   \
 178         struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, TIMER_DEFERRABLE)
 179
 180 /*
 181  * initialize a work item's function pointer
 182  */
 183 #define PREPARE_WORK(_work, _func)                                      \
 184         do {                                                            \
 185                 (_work)->func = (_func);                                \
 186         } while (0)
 187
 188 #define PREPARE_DELAYED_WORK(_work, _func)                              \
 189         PREPARE_WORK(&(_work)->work, (_func))
 190
 191 #ifdef CONFIG_DEBUG_OBJECTS_WORK
 192 extern void __init_work(struct work_struct *work, int onstack);
 193 extern void destroy_work_on_stack(struct work_struct *work);
 194 static inline unsigned int work_static(struct work_struct *work)
 195 {
 196         return *work_data_bits(work) & WORK_STRUCT_STATIC;
 197 }
 198 #else
 199 static inline void __init_work(struct work_struct *work, int onstack) { }
 200 static inline void destroy_work_on_stack(struct work_struct *work) { }
 201 static inline unsigned int work_static(struct work_struct *work) { return 0; }
 202 #endif
 203
 204 /*
 205  * initialize all of a work item in one go
 206  *
 207  * NOTE! No point in using "atomic_long_set()": using a direct
 208  * assignment of the work data initializer allows the compiler
 209  * to generate better code.
 210  */
 211 #ifdef CONFIG_LOCKDEP
 212 #define __INIT_WORK(_work, _func, _onstack)                             \
 213         do {                                                            \
 214                 static struct lock_class_key __key;                     \
 215                                                                         \
 216                 __init_work((_work), _onstack);                         \
 217                 (_work)->data = (atomic_long_t) WORK_DATA_INIT();       \
 218                 lockdep_init_map(&(_work)->lockdep_map, #_work, &__key, 0); \
 219                 INIT_LIST_HEAD(&(_work)->entry);                        \
 220                 PREPARE_WORK((_work), (_func));                         \
 221         } while (0)
 222 #else
 223 #define __INIT_WORK(_work, _func, _onstack)                             \
 224         do {                                                            \
 225                 __init_work((_work), _onstack);                         \
 226                 (_work)->data = (atomic_long_t) WORK_DATA_INIT();       \
 227                 INIT_LIST_HEAD(&(_work)->entry);                        \
 228                 PREPARE_WORK((_work), (_func));                         \
 229         } while (0)
 230 #endif
 231
 232 #define INIT_WORK(_work, _func)                                         \
 233         do {                                                            \
 234                 __INIT_WORK((_work), (_func), 0);                       \
 235         } while (0)
 236
 237 #define INIT_WORK_ONSTACK(_work, _func)                                 \
 238         do {                                                            \
 239                 __INIT_WORK((_work), (_func), 1);                       \
 240         } while (0)
 241
 242 #define __INIT_DELAYED_WORK(_work, _func, _tflags)                      \
 243         do {                                                            \
 244                 INIT_WORK(&(_work)->work, (_func));                     \
 245                 __setup_timer(&(_work)->timer, delayed_work_timer_fn,   \
 246                               (unsigned long)(_work),                   \
 247                               (_tflags) | TIMER_IRQSAFE);               \
 248         } while (0)
 249
 250 #define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags)              \
 251         do {                                                            \
 252                 INIT_WORK_ONSTACK(&(_work)->work, (_func));             \
 253                 __setup_timer_on_stack(&(_work)->timer,                 \
 254                                        delayed_work_timer_fn,           \
 255                                        (unsigned long)(_work),          \
 256                                        (_tflags) | TIMER_IRQSAFE);      \
 257         } while (0)
 258
 259 #define INIT_DELAYED_WORK(_work, _func)                                 \
 260         __INIT_DELAYED_WORK(_work, _func, 0)
 261
 262 #define INIT_DELAYED_WORK_ONSTACK(_work, _func)                         \
 263         __INIT_DELAYED_WORK_ONSTACK(_work, _func, 0)
 264
 265 #define INIT_DEFERRABLE_WORK(_work, _func)                              \
 266         __INIT_DELAYED_WORK(_work, _func, TIMER_DEFERRABLE)
 267
 268 #define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func)                      \
 269         __INIT_DELAYED_WORK_ONSTACK(_work, _func, TIMER_DEFERRABLE)
 270
 271 /**
 272  * work_pending - Find out whether a work item is currently pending
 273  * @work: The work item in question
 274  */
 275 #define work_pending(work) \
 276         test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
 277
 278 /**
 279  * delayed_work_pending - Find out whether a delayable work item is currently
 280  * pending
 281  * @work: The work item in question
 282  */
 283 #define delayed_work_pending(w) \
 284         work_pending(&(w)->work)
 285
 286 /**
 287  * work_clear_pending - for internal use only, mark a work item as not pending
 288  * @work: The work item in question
 289  */
 290 #define work_clear_pending(work) \
 291         clear_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
 292
 293 /*
 294  * Workqueue flags and constants.  For details, please refer to
 295  * Documentation/workqueue.txt.
 296  */
 297 enum {
 298         WQ_NON_REENTRANT        = 1 << 0, /* guarantee non-reentrance */
 299         WQ_UNBOUND              = 1 << 1, /* not bound to any cpu */
 300         WQ_FREEZABLE            = 1 << 2, /* freeze during suspend */
 301         WQ_MEM_RECLAIM          = 1 << 3, /* may be used for memory reclaim */
 302         WQ_HIGHPRI              = 1 << 4, /* high priority */
 303         WQ_CPU_INTENSIVE        = 1 << 5, /* cpu instensive workqueue */
 304         WQ_SYSFS                = 1 << 6, /* visible in sysfs, see wq_sysfs_register() */
 305
 306         /*
 307          * Per-cpu workqueues are generally preferred because they tend to
 308          * show better performance thanks to cache locality.  Per-cpu
 309          * workqueues exclude the scheduler from choosing the CPU to
 310          * execute the worker threads, which has an unfortunate side effect
 311          * of increasing power consumption.
 312          *
 313          * The scheduler considers a CPU idle if it doesn't have any task
 314          * to execute and tries to keep idle cores idle to conserve power;
 315          * however, for example, a per-cpu work item scheduled from an
 316          * interrupt handler on an idle CPU will force the scheduler to
 317          * excute the work item on that CPU breaking the idleness, which in
 318          * turn may lead to more scheduling choices which are sub-optimal
 319          * in terms of power consumption.
 320          *
 321          * Workqueues marked with WQ_POWER_EFFICIENT are per-cpu by default
 322          * but become unbound if workqueue.power_efficient kernel param is
 323          * specified.  Per-cpu workqueues which are identified to
 324          * contribute significantly to power-consumption are identified and
 325          * marked with this flag and enabling the power_efficient mode
 326          * leads to noticeable power saving at the cost of small
 327          * performance disadvantage.
 328          *
 329          * http://thread.gmane.org/gmane.linux.kernel/1480396
 330          */
 331         WQ_POWER_EFFICIENT      = 1 << 7,
 332
 333         __WQ_DRAINING           = 1 << 16, /* internal: workqueue is draining */
 334         __WQ_ORDERED            = 1 << 17, /* internal: workqueue is ordered */
 335
 336         WQ_MAX_ACTIVE           = 512,    /* I like 512, better ideas? */
 337         WQ_MAX_UNBOUND_PER_CPU  = 4,      /* 4 * #cpus for unbound wq */
 338         WQ_DFL_ACTIVE           = WQ_MAX_ACTIVE / 2,
 339 };
 340
 341 /* unbound wq's aren't per-cpu, scale max_active according to #cpus */
 342 #define WQ_UNBOUND_MAX_ACTIVE   \
 343         max_t(int, WQ_MAX_ACTIVE, num_possible_cpus() * WQ_MAX_UNBOUND_PER_CPU)
 344
 345 /*
 346  * System-wide workqueues which are always present.
 347  *
 348  * system_wq is the one used by schedule[_delayed]_work[_on]().
 349  * Multi-CPU multi-threaded.  There are users which expect relatively
 350  * short queue flush time.  Don't queue works which can run for too
 351  * long.
 352  *
 353  * system_long_wq is similar to system_wq but may host long running
 354  * works.  Queue flushing might take relatively long.
 355  *
 356  * system_unbound_wq is unbound workqueue.  Workers are not bound to
 357  * any specific CPU, not concurrency managed, and all queued works are
 358  * executed immediately as long as max_active limit is not reached and
 359  * resources are available.
 360  *
 361  * system_freezable_wq is equivalent to system_wq except that it's
 362  * freezable.
 363  *
 364  * *_power_efficient_wq are inclined towards saving power and converted
 365  * into WQ_UNBOUND variants if 'wq_power_efficient' is enabled; otherwise,
 366  * they are same as their non-power-efficient counterparts - e.g.
 367  * system_power_efficient_wq is identical to system_wq if
 368  * 'wq_power_efficient' is disabled.  See WQ_POWER_EFFICIENT for more info.
 369  */
 370 extern struct workqueue_struct *system_wq;
 371 extern struct workqueue_struct *system_long_wq;
 372 extern struct workqueue_struct *system_unbound_wq;
 373 extern struct workqueue_struct *system_freezable_wq;
 374 extern struct workqueue_struct *system_power_efficient_wq;
 375 extern struct workqueue_struct *system_freezable_power_efficient_wq;
 376
 377 static inline struct workqueue_struct * __deprecated __system_nrt_wq(void)
 378 {
 379         return system_wq;
 380 }
 381
 382 static inline struct workqueue_struct * __deprecated __system_nrt_freezable_wq(void)
 383 {
 384         return system_freezable_wq;
 385 }
 386
 387 /* equivlalent to system_wq and system_freezable_wq, deprecated */
 388 #define system_nrt_wq                   __system_nrt_wq()
 389 #define system_nrt_freezable_wq         __system_nrt_freezable_wq()
 390
 391 extern struct workqueue_struct *
 392 __alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active,
 393         struct lock_class_key *key, const char *lock_name, ...) __printf(1, 6);
 394
 395 /**
 396  * alloc_workqueue - allocate a workqueue
 397  * @fmt: printf format for the name of the workqueue
 398  * @flags: WQ_* flags
 399  * @max_active: max in-flight work items, 0 for default
 400  * @args: args for @fmt
 401  *
 402  * Allocate a workqueue with the specified parameters.  For detailed
 403  * information on WQ_* flags, please refer to Documentation/workqueue.txt.
 404  *
 405  * The __lock_name macro dance is to guarantee that single lock_class_key
 406  * doesn't end up with different namesm, which isn't allowed by lockdep.
 407  *
 408  * RETURNS:
 409  * Pointer to the allocated workqueue on success, %NULL on failure.
 410  */
 411 #ifdef CONFIG_LOCKDEP
 412 #define alloc_workqueue(fmt, flags, max_active, args...)                \
 413 ({                                                                      \
 414         static struct lock_class_key __key;                             \
 415         const char *__lock_name;                                        \
 416                                                                         \
 417         if (__builtin_constant_p(fmt))                                  \
 418                 __lock_name = (fmt);                                    \
 419         else                                                            \
 420                 __lock_name = #fmt;                                     \
 421                                                                         \
 422         __alloc_workqueue_key((fmt), (flags), (max_active),             \
 423                               &__key, __lock_name, ##args);             \
 424 })
 425 #else
 426 #define alloc_workqueue(fmt, flags, max_active, args...)                \
 427         __alloc_workqueue_key((fmt), (flags), (max_active),             \
 428                               NULL, NULL, ##args)
 429 #endif
 430
 431 /**
 432  * alloc_ordered_workqueue - allocate an ordered workqueue
 433  * @fmt: printf format for the name of the workqueue
 434  * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
 435  * @args: args for @fmt
 436  *
 437  * Allocate an ordered workqueue.  An ordered workqueue executes at
 438  * most one work item at any given time in the queued order.  They are
 439  * implemented as unbound workqueues with @max_active of one.
 440  *
 441  * RETURNS:
 442  * Pointer to the allocated workqueue on success, %NULL on failure.
 443  */
 444 #define alloc_ordered_workqueue(fmt, flags, args...)                    \
 445         alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | (flags), 1, ##args)
 446
 447 #define create_workqueue(name)                                          \
 448         alloc_workqueue("%s", WQ_MEM_RECLAIM, 1, (name))
 449 #define create_freezable_workqueue(name)                                \
 450         alloc_workqueue("%s", WQ_FREEZABLE | WQ_UNBOUND | WQ_MEM_RECLAIM, \
 451                         1, (name))
 452 #define create_singlethread_workqueue(name)                             \
 453         alloc_workqueue("%s", WQ_UNBOUND | WQ_MEM_RECLAIM, 1, (name))
 454
 455 extern void destroy_workqueue(struct workqueue_struct *wq);
 456
 457 struct workqueue_attrs *alloc_workqueue_attrs(gfp_t gfp_mask);
 458 void free_workqueue_attrs(struct workqueue_attrs *attrs);
 459 int apply_workqueue_attrs(struct workqueue_struct *wq,
 460                           const struct workqueue_attrs *attrs);
 461
 462 extern bool queue_work_on(int cpu, struct workqueue_struct *wq,
 463                         struct work_struct *work);
 464 extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
 465                         struct delayed_work *work, unsigned long delay);
 466 extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
 467                         struct delayed_work *dwork, unsigned long delay);
 468
 469 extern void flush_workqueue(struct workqueue_struct *wq);
 470 extern void drain_workqueue(struct workqueue_struct *wq);
 471 extern void flush_scheduled_work(void);
 472
 473 extern int schedule_on_each_cpu(work_func_t func);
 474
 475 int execute_in_process_context(work_func_t fn, struct execute_work *);
 476
 477 extern bool flush_work(struct work_struct *work);
 478 extern bool cancel_work_sync(struct work_struct *work);
 479
 480 extern bool flush_delayed_work(struct delayed_work *dwork);
 481 extern bool cancel_delayed_work(struct delayed_work *dwork);
 482 extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
 483
 484 extern void workqueue_set_max_active(struct workqueue_struct *wq,
 485                                      int max_active);
 486 extern bool current_is_workqueue_rescuer(void);
 487 extern bool workqueue_congested(int cpu, struct workqueue_struct *wq);
 488 extern unsigned int work_busy(struct work_struct *work);
 489 extern __printf(1, 2) void set_worker_desc(const char *fmt, ...);
 490 extern void print_worker_info(const char *log_lvl, struct task_struct *task);
 491
 492 /**
 493  * queue_work - queue work on a workqueue
 494  * @wq: workqueue to use
 495  * @work: work to queue
 496  *
 497  * Returns %false if @work was already on a queue, %true otherwise.
 498  *
 499  * We queue the work to the CPU on which it was submitted, but if the CPU dies
 500  * it can be processed by another CPU.
 501  */
 502 static inline bool queue_work(struct workqueue_struct *wq,
 503                               struct work_struct *work)
 504 {
 505         return queue_work_on(WORK_CPU_UNBOUND, wq, work);
 506 }
 507
 508 /**
 509  * queue_delayed_work - queue work on a workqueue after delay
 510  * @wq: workqueue to use
 511  * @dwork: delayable work to queue
 512  * @delay: number of jiffies to wait before queueing
 513  *
 514  * Equivalent to queue_delayed_work_on() but tries to use the local CPU.
 515  */
 516 static inline bool queue_delayed_work(struct workqueue_struct *wq,
 517                                       struct delayed_work *dwork,
 518                                       unsigned long delay)
 519 {
 520         return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
 521 }
 522
 523 /**
 524  * mod_delayed_work - modify delay of or queue a delayed work
 525  * @wq: workqueue to use
 526  * @dwork: work to queue
 527  * @delay: number of jiffies to wait before queueing
 528  *
 529  * mod_delayed_work_on() on local CPU.
 530  */
 531 static inline bool mod_delayed_work(struct workqueue_struct *wq,
 532                                     struct delayed_work *dwork,
 533                                     unsigned long delay)
 534 {
 535         return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
 536 }
 537
 538 /**
 539  * schedule_work_on - put work task on a specific cpu
 540  * @cpu: cpu to put the work task on
 541  * @work: job to be done
 542  *
 543  * This puts a job on a specific cpu
 544  */
 545 static inline bool schedule_work_on(int cpu, struct work_struct *work)
 546 {
 547         return queue_work_on(cpu, system_wq, work);
 548 }
 549
 550 /**
 551  * schedule_work - put work task in global workqueue
 552  * @work: job to be done
 553  *
 554  * Returns %false if @work was already on the kernel-global workqueue and
 555  * %true otherwise.
 556  *
 557  * This puts a job in the kernel-global workqueue if it was not already
 558  * queued and leaves it in the same position on the kernel-global
 559  * workqueue otherwise.
 560  */
 561 static inline bool schedule_work(struct work_struct *work)
 562 {
 563         return queue_work(system_wq, work);
 564 }
 565
 566 /**
 567  * schedule_delayed_work_on - queue work in global workqueue on CPU after delay
 568  * @cpu: cpu to use
 569  * @dwork: job to be done
 570  * @delay: number of jiffies to wait
 571  *
 572  * After waiting for a given time this puts a job in the kernel-global
 573  * workqueue on the specified CPU.
 574  */
 575 static inline bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork,
 576                                             unsigned long delay)
 577 {
 578         return queue_delayed_work_on(cpu, system_wq, dwork, delay);
 579 }
 580
 581 /**
 582  * schedule_delayed_work - put work task in global workqueue after delay
 583  * @dwork: job to be done
 584  * @delay: number of jiffies to wait or 0 for immediate execution
 585  *
 586  * After waiting for a given time this puts a job in the kernel-global
 587  * workqueue.
 588  */
 589 static inline bool schedule_delayed_work(struct delayed_work *dwork,
 590                                          unsigned long delay)
 591 {
 592         return queue_delayed_work(system_wq, dwork, delay);
 593 }
 594
 595 /**
 596  * keventd_up - is workqueue initialized yet?
 597  */
 598 static inline bool keventd_up(void)
 599 {
 600         return system_wq != NULL;
 601 }
 602
 603 /*
 604  * Like above, but uses del_timer() instead of del_timer_sync(). This means,
 605  * if it returns 0 the timer function may be running and the queueing is in
 606  * progress.
 607  */
 608 static inline bool __deprecated __cancel_delayed_work(struct delayed_work *work)
 609 {
 610         bool ret;
 611
 612         ret = del_timer(&work->timer);
 613         if (ret)
 614                 work_clear_pending(&work->work);
 615         return ret;
 616 }
 617
 618 /* used to be different but now identical to flush_work(), deprecated */
 619 static inline bool __deprecated flush_work_sync(struct work_struct *work)
 620 {
 621         return flush_work(work);
 622 }
 623
 624 /* used to be different but now identical to flush_delayed_work(), deprecated */
 625 static inline bool __deprecated flush_delayed_work_sync(struct delayed_work *dwork)
 626 {
 627         return flush_delayed_work(dwork);
 628 }
 629
 630 #ifndef CONFIG_SMP
 631 static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
 632 {
 633         return fn(arg);
 634 }
 635 #else
 636 long work_on_cpu(int cpu, long (*fn)(void *), void *arg);
 637 #endif /* CONFIG_SMP */
 638
 639 #ifdef CONFIG_FREEZER
 640 extern void freeze_workqueues_begin(void);
 641 extern bool freeze_workqueues_busy(void);
 642 extern void thaw_workqueues(void);
 643 #endif /* CONFIG_FREEZER */
 644
 645 #ifdef CONFIG_SYSFS
 646 int workqueue_sysfs_register(struct workqueue_struct *wq);
 647 #else   /* CONFIG_SYSFS */
 648 static inline int workqueue_sysfs_register(struct workqueue_struct *wq)
 649 { return 0; }
 650 #endif  /* CONFIG_SYSFS */
 651
 652 #endif