include/linux/workqueue.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * workqueue.h --- work queue handling for Linux.
   4  */
   5
   6 #ifndef _LINUX_WORKQUEUE_H
   7 #define _LINUX_WORKQUEUE_H
   8
   9 #include <linux/timer.h>
  10 #include <linux/linkage.h>
  11 #include <linux/bitops.h>
  12 #include <linux/lockdep.h>
  13 #include <linux/threads.h>
  14 #include <linux/atomic.h>
  15 #include <linux/cpumask.h>
  16
  17 struct workqueue_struct;
  18
  19 struct work_struct;
  20 typedef void (*work_func_t)(struct work_struct *work);
  21 void delayed_work_timer_fn(struct timer_list *t);
  22
  23 /*
  24  * The first word is the work queue pointer and the flags rolled into
  25  * one
  26  */
  27 #define work_data_bits(work) ((unsigned long *)(&(work)->data))
  28
  29 enum {
  30         WORK_STRUCT_PENDING_BIT = 0,    /* work item is pending execution */
  31         WORK_STRUCT_DELAYED_BIT = 1,    /* work item is delayed */
  32         WORK_STRUCT_PWQ_BIT     = 2,    /* data points to pwq */
  33         WORK_STRUCT_LINKED_BIT  = 3,    /* next work is linked to this one */
  34 #ifdef CONFIG_DEBUG_OBJECTS_WORK
  35         WORK_STRUCT_STATIC_BIT  = 4,    /* static initializer (debugobjects) */
  36         WORK_STRUCT_COLOR_SHIFT = 5,    /* color for workqueue flushing */
  37 #else
  38         WORK_STRUCT_COLOR_SHIFT = 4,    /* color for workqueue flushing */
  39 #endif
  40
  41         WORK_STRUCT_COLOR_BITS  = 4,
  42
  43         WORK_STRUCT_PENDING     = 1 << WORK_STRUCT_PENDING_BIT,
  44         WORK_STRUCT_DELAYED     = 1 << WORK_STRUCT_DELAYED_BIT,
  45         WORK_STRUCT_PWQ         = 1 << WORK_STRUCT_PWQ_BIT,
  46         WORK_STRUCT_LINKED      = 1 << WORK_STRUCT_LINKED_BIT,
  47 #ifdef CONFIG_DEBUG_OBJECTS_WORK
  48         WORK_STRUCT_STATIC      = 1 << WORK_STRUCT_STATIC_BIT,
  49 #else
  50         WORK_STRUCT_STATIC      = 0,
  51 #endif
  52
  53         /*
  54          * The last color is no color used for works which don't
  55          * participate in workqueue flushing.
  56          */
  57         WORK_NR_COLORS          = (1 << WORK_STRUCT_COLOR_BITS) - 1,
  58         WORK_NO_COLOR           = WORK_NR_COLORS,
  59
  60         /* not bound to any CPU, prefer the local CPU */
  61         WORK_CPU_UNBOUND        = NR_CPUS,
  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((unsigned long)WORK_STRUCT_NO_POOL)
 111 #define WORK_DATA_STATIC_INIT() \
 112         ATOMIC_LONG_INIT((unsigned long)(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  * struct workqueue_attrs - A struct for workqueue attributes.
 125  *
 126  * This can be used to change attributes of an unbound workqueue.
 127  */
 128 struct workqueue_attrs {
 129         /**
 130          * @nice: nice level
 131          */
 132         int nice;
 133
 134         /**
 135          * @cpumask: allowed CPUs
 136          */
 137         cpumask_var_t cpumask;
 138
 139         /**
 140          * @no_numa: disable NUMA affinity
 141          *
 142          * Unlike other fields, ``no_numa`` isn't a property of a worker_pool. It
 143          * only modifies how :c:func:`apply_workqueue_attrs` select pools and thus
 144          * doesn't participate in pool hash calculations or equality comparisons.
 145          */
 146         bool no_numa;
 147 };
 148
 149 static inline struct delayed_work *to_delayed_work(struct work_struct *work)
 150 {
 151         return container_of(work, struct delayed_work, work);
 152 }
 153
 154 struct execute_work {
 155         struct work_struct work;
 156 };
 157
 158 #ifdef CONFIG_LOCKDEP
 159 /*
 160  * NB: because we have to copy the lockdep_map, setting _key
 161  * here is required, otherwise it could get initialised to the
 162  * copy of the lockdep_map!
 163  */
 164 #define __WORK_INIT_LOCKDEP_MAP(n, k) \
 165         .lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k),
 166 #else
 167 #define __WORK_INIT_LOCKDEP_MAP(n, k)
 168 #endif
 169
 170 #define __WORK_INITIALIZER(n, f) {                                      \
 171         .data = WORK_DATA_STATIC_INIT(),                                \
 172         .entry  = { &(n).entry, &(n).entry },                           \
 173         .func = (f),                                                    \
 174         __WORK_INIT_LOCKDEP_MAP(#n, &(n))                               \
 175         }
 176
 177 #define __DELAYED_WORK_INITIALIZER(n, f, tflags) {                      \
 178         .work = __WORK_INITIALIZER((n).work, (f)),                      \
 179         .timer = __TIMER_INITIALIZER((TIMER_FUNC_TYPE)delayed_work_timer_fn,\
 180                                      (tflags) | TIMER_IRQSAFE),         \
 181         }
 182
 183 #define DECLARE_WORK(n, f)                                              \
 184         struct work_struct n = __WORK_INITIALIZER(n, f)
 185
 186 #define DECLARE_DELAYED_WORK(n, f)                                      \
 187         struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, 0)
 188
 189 #define DECLARE_DEFERRABLE_WORK(n, f)                                   \
 190         struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, TIMER_DEFERRABLE)
 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 extern void destroy_delayed_work_on_stack(struct delayed_work *work);
 196 static inline unsigned int work_static(struct work_struct *work)
 197 {
 198         return *work_data_bits(work) & WORK_STRUCT_STATIC;
 199 }
 200 #else
 201 static inline void __init_work(struct work_struct *work, int onstack) { }
 202 static inline void destroy_work_on_stack(struct work_struct *work) { }
 203 static inline void destroy_delayed_work_on_stack(struct delayed_work *work) { }
 204 static inline unsigned int work_static(struct work_struct *work) { return 0; }
 205 #endif
 206
 207 /*
 208  * initialize all of a work item in one go
 209  *
 210  * NOTE! No point in using "atomic_long_set()": using a direct
 211  * assignment of the work data initializer allows the compiler
 212  * to generate better code.
 213  */
 214 #ifdef CONFIG_LOCKDEP
 215 #define __INIT_WORK(_work, _func, _onstack)                             \
 216         do {                                                            \
 217                 static struct lock_class_key __key;                     \
 218                                                                         \
 219                 __init_work((_work), _onstack);                         \
 220                 (_work)->data = (atomic_long_t) WORK_DATA_INIT();       \
 221                 lockdep_init_map(&(_work)->lockdep_map, "(work_completion)"#_work, &__key, 0); \
 222                 INIT_LIST_HEAD(&(_work)->entry);                        \
 223                 (_work)->func = (_func);                                \
 224         } while (0)
 225 #else
 226 #define __INIT_WORK(_work, _func, _onstack)                             \
 227         do {                                                            \
 228                 __init_work((_work), _onstack);                         \
 229                 (_work)->data = (atomic_long_t) WORK_DATA_INIT();       \
 230                 INIT_LIST_HEAD(&(_work)->entry);                        \
 231                 (_work)->func = (_func);                                \
 232         } while (0)
 233 #endif
 234
 235 #define INIT_WORK(_work, _func)                                         \
 236         __INIT_WORK((_work), (_func), 0)
 237
 238 #define INIT_WORK_ONSTACK(_work, _func)                                 \
 239         __INIT_WORK((_work), (_func), 1)
 240
 241 #define __INIT_DELAYED_WORK(_work, _func, _tflags)                      \
 242         do {                                                            \
 243                 INIT_WORK(&(_work)->work, (_func));                     \
 244                 __setup_timer(&(_work)->timer,                          \
 245                               (TIMER_FUNC_TYPE)delayed_work_timer_fn,   \
 246                               (_tflags) | TIMER_IRQSAFE);               \
 247         } while (0)
 248
 249 #define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags)              \
 250         do {                                                            \
 251                 INIT_WORK_ONSTACK(&(_work)->work, (_func));             \
 252                 __setup_timer_on_stack(&(_work)->timer,                 \
 253                                        (TIMER_FUNC_TYPE)delayed_work_timer_fn,\
 254                                        (_tflags) | TIMER_IRQSAFE);      \
 255         } while (0)
 256
 257 #define INIT_DELAYED_WORK(_work, _func)                                 \
 258         __INIT_DELAYED_WORK(_work, _func, 0)
 259
 260 #define INIT_DELAYED_WORK_ONSTACK(_work, _func)                         \
 261         __INIT_DELAYED_WORK_ONSTACK(_work, _func, 0)
 262
 263 #define INIT_DEFERRABLE_WORK(_work, _func)                              \
 264         __INIT_DELAYED_WORK(_work, _func, TIMER_DEFERRABLE)
 265
 266 #define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func)                      \
 267         __INIT_DELAYED_WORK_ONSTACK(_work, _func, TIMER_DEFERRABLE)
 268
 269 /**
 270  * work_pending - Find out whether a work item is currently pending
 271  * @work: The work item in question
 272  */
 273 #define work_pending(work) \
 274         test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
 275
 276 /**
 277  * delayed_work_pending - Find out whether a delayable work item is currently
 278  * pending
 279  * @w: The work item in question
 280  */
 281 #define delayed_work_pending(w) \
 282         work_pending(&(w)->work)
 283
 284 /*
 285  * Workqueue flags and constants.  For details, please refer to
 286  * Documentation/core-api/workqueue.rst.
 287  */
 288 enum {
 289         WQ_UNBOUND              = 1 << 1, /* not bound to any cpu */
 290         WQ_FREEZABLE            = 1 << 2, /* freeze during suspend */
 291         WQ_MEM_RECLAIM          = 1 << 3, /* may be used for memory reclaim */
 292         WQ_HIGHPRI              = 1 << 4, /* high priority */
 293         WQ_CPU_INTENSIVE        = 1 << 5, /* cpu intensive workqueue */
 294         WQ_SYSFS                = 1 << 6, /* visible in sysfs, see wq_sysfs_register() */
 295
 296         /*
 297          * Per-cpu workqueues are generally preferred because they tend to
 298          * show better performance thanks to cache locality.  Per-cpu
 299          * workqueues exclude the scheduler from choosing the CPU to
 300          * execute the worker threads, which has an unfortunate side effect
 301          * of increasing power consumption.
 302          *
 303          * The scheduler considers a CPU idle if it doesn't have any task
 304          * to execute and tries to keep idle cores idle to conserve power;
 305          * however, for example, a per-cpu work item scheduled from an
 306          * interrupt handler on an idle CPU will force the scheduler to
 307          * excute the work item on that CPU breaking the idleness, which in
 308          * turn may lead to more scheduling choices which are sub-optimal
 309          * in terms of power consumption.
 310          *
 311          * Workqueues marked with WQ_POWER_EFFICIENT are per-cpu by default
 312          * but become unbound if workqueue.power_efficient kernel param is
 313          * specified.  Per-cpu workqueues which are identified to
 314          * contribute significantly to power-consumption are identified and
 315          * marked with this flag and enabling the power_efficient mode
 316          * leads to noticeable power saving at the cost of small
 317          * performance disadvantage.
 318          *
 319          * http://thread.gmane.org/gmane.linux.kernel/1480396
 320          */
 321         WQ_POWER_EFFICIENT      = 1 << 7,
 322
 323         __WQ_DRAINING           = 1 << 16, /* internal: workqueue is draining */
 324         __WQ_ORDERED            = 1 << 17, /* internal: workqueue is ordered */
 325         __WQ_LEGACY             = 1 << 18, /* internal: create*_workqueue() */
 326         __WQ_ORDERED_EXPLICIT   = 1 << 19, /* internal: alloc_ordered_workqueue() */
 327
 328         WQ_MAX_ACTIVE           = 512,    /* I like 512, better ideas? */
 329         WQ_MAX_UNBOUND_PER_CPU  = 4,      /* 4 * #cpus for unbound wq */
 330         WQ_DFL_ACTIVE           = WQ_MAX_ACTIVE / 2,
 331 };
 332
 333 /* unbound wq's aren't per-cpu, scale max_active according to #cpus */
 334 #define WQ_UNBOUND_MAX_ACTIVE   \
 335         max_t(int, WQ_MAX_ACTIVE, num_possible_cpus() * WQ_MAX_UNBOUND_PER_CPU)
 336
 337 /*
 338  * System-wide workqueues which are always present.
 339  *
 340  * system_wq is the one used by schedule[_delayed]_work[_on]().
 341  * Multi-CPU multi-threaded.  There are users which expect relatively
 342  * short queue flush time.  Don't queue works which can run for too
 343  * long.
 344  *
 345  * system_highpri_wq is similar to system_wq but for work items which
 346  * require WQ_HIGHPRI.
 347  *
 348  * system_long_wq is similar to system_wq but may host long running
 349  * works.  Queue flushing might take relatively long.
 350  *
 351  * system_unbound_wq is unbound workqueue.  Workers are not bound to
 352  * any specific CPU, not concurrency managed, and all queued works are
 353  * executed immediately as long as max_active limit is not reached and
 354  * resources are available.
 355  *
 356  * system_freezable_wq is equivalent to system_wq except that it's
 357  * freezable.
 358  *
 359  * *_power_efficient_wq are inclined towards saving power and converted
 360  * into WQ_UNBOUND variants if 'wq_power_efficient' is enabled; otherwise,
 361  * they are same as their non-power-efficient counterparts - e.g.
 362  * system_power_efficient_wq is identical to system_wq if
 363  * 'wq_power_efficient' is disabled.  See WQ_POWER_EFFICIENT for more info.
 364  */
 365 extern struct workqueue_struct *system_wq;
 366 extern struct workqueue_struct *system_highpri_wq;
 367 extern struct workqueue_struct *system_long_wq;
 368 extern struct workqueue_struct *system_unbound_wq;
 369 extern struct workqueue_struct *system_freezable_wq;
 370 extern struct workqueue_struct *system_power_efficient_wq;
 371 extern struct workqueue_struct *system_freezable_power_efficient_wq;
 372
 373 extern struct workqueue_struct *
 374 __alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active,
 375         struct lock_class_key *key, const char *lock_name, ...) __printf(1, 6);
 376
 377 /**
 378  * alloc_workqueue - allocate a workqueue
 379  * @fmt: printf format for the name of the workqueue
 380  * @flags: WQ_* flags
 381  * @max_active: max in-flight work items, 0 for default
 382  * @args...: args for @fmt
 383  *
 384  * Allocate a workqueue with the specified parameters.  For detailed
 385  * information on WQ_* flags, please refer to
 386  * Documentation/core-api/workqueue.rst.
 387  *
 388  * The __lock_name macro dance is to guarantee that single lock_class_key
 389  * doesn't end up with different namesm, which isn't allowed by lockdep.
 390  *
 391  * RETURNS:
 392  * Pointer to the allocated workqueue on success, %NULL on failure.
 393  */
 394 #ifdef CONFIG_LOCKDEP
 395 #define alloc_workqueue(fmt, flags, max_active, args...)                \
 396 ({                                                                      \
 397         static struct lock_class_key __key;                             \
 398         const char *__lock_name;                                        \
 399                                                                         \
 400         __lock_name = "(wq_completion)"#fmt#args;                       \
 401                                                                         \
 402         __alloc_workqueue_key((fmt), (flags), (max_active),             \
 403                               &__key, __lock_name, ##args);             \
 404 })
 405 #else
 406 #define alloc_workqueue(fmt, flags, max_active, args...)                \
 407         __alloc_workqueue_key((fmt), (flags), (max_active),             \
 408                               NULL, NULL, ##args)
 409 #endif
 410
 411 /**
 412  * alloc_ordered_workqueue - allocate an ordered workqueue
 413  * @fmt: printf format for the name of the workqueue
 414  * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
 415  * @args...: args for @fmt
 416  *
 417  * Allocate an ordered workqueue.  An ordered workqueue executes at
 418  * most one work item at any given time in the queued order.  They are
 419  * implemented as unbound workqueues with @max_active of one.
 420  *
 421  * RETURNS:
 422  * Pointer to the allocated workqueue on success, %NULL on failure.
 423  */
 424 #define alloc_ordered_workqueue(fmt, flags, args...)                    \
 425         alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED |                \
 426                         __WQ_ORDERED_EXPLICIT | (flags), 1, ##args)
 427
 428 #define create_workqueue(name)                                          \
 429         alloc_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, 1, (name))
 430 #define create_freezable_workqueue(name)                                \
 431         alloc_workqueue("%s", __WQ_LEGACY | WQ_FREEZABLE | WQ_UNBOUND | \
 432                         WQ_MEM_RECLAIM, 1, (name))
 433 #define create_singlethread_workqueue(name)                             \
 434         alloc_ordered_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, name)
 435
 436 extern void destroy_workqueue(struct workqueue_struct *wq);
 437
 438 struct workqueue_attrs *alloc_workqueue_attrs(gfp_t gfp_mask);
 439 void free_workqueue_attrs(struct workqueue_attrs *attrs);
 440 int apply_workqueue_attrs(struct workqueue_struct *wq,
 441                           const struct workqueue_attrs *attrs);
 442 int workqueue_set_unbound_cpumask(cpumask_var_t cpumask);
 443
 444 extern bool queue_work_on(int cpu, struct workqueue_struct *wq,
 445                         struct work_struct *work);
 446 extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
 447                         struct delayed_work *work, unsigned long delay);
 448 extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
 449                         struct delayed_work *dwork, unsigned long delay);
 450
 451 extern void flush_workqueue(struct workqueue_struct *wq);
 452 extern void drain_workqueue(struct workqueue_struct *wq);
 453
 454 extern int schedule_on_each_cpu(work_func_t func);
 455
 456 int execute_in_process_context(work_func_t fn, struct execute_work *);
 457
 458 extern bool flush_work(struct work_struct *work);
 459 extern bool cancel_work(struct work_struct *work);
 460 extern bool cancel_work_sync(struct work_struct *work);
 461
 462 extern bool flush_delayed_work(struct delayed_work *dwork);
 463 extern bool cancel_delayed_work(struct delayed_work *dwork);
 464 extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
 465
 466 extern void workqueue_set_max_active(struct workqueue_struct *wq,
 467                                      int max_active);
 468 extern bool current_is_workqueue_rescuer(void);
 469 extern bool workqueue_congested(int cpu, struct workqueue_struct *wq);
 470 extern unsigned int work_busy(struct work_struct *work);
 471 extern __printf(1, 2) void set_worker_desc(const char *fmt, ...);
 472 extern void print_worker_info(const char *log_lvl, struct task_struct *task);
 473 extern void show_workqueue_state(void);
 474
 475 /**
 476  * queue_work - queue work on a workqueue
 477  * @wq: workqueue to use
 478  * @work: work to queue
 479  *
 480  * Returns %false if @work was already on a queue, %true otherwise.
 481  *
 482  * We queue the work to the CPU on which it was submitted, but if the CPU dies
 483  * it can be processed by another CPU.
 484  */
 485 static inline bool queue_work(struct workqueue_struct *wq,
 486                               struct work_struct *work)
 487 {
 488         return queue_work_on(WORK_CPU_UNBOUND, wq, work);
 489 }
 490
 491 /**
 492  * queue_delayed_work - queue work on a workqueue after delay
 493  * @wq: workqueue to use
 494  * @dwork: delayable work to queue
 495  * @delay: number of jiffies to wait before queueing
 496  *
 497  * Equivalent to queue_delayed_work_on() but tries to use the local CPU.
 498  */
 499 static inline bool queue_delayed_work(struct workqueue_struct *wq,
 500                                       struct delayed_work *dwork,
 501                                       unsigned long delay)
 502 {
 503         return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
 504 }
 505
 506 /**
 507  * mod_delayed_work - modify delay of or queue a delayed work
 508  * @wq: workqueue to use
 509  * @dwork: work to queue
 510  * @delay: number of jiffies to wait before queueing
 511  *
 512  * mod_delayed_work_on() on local CPU.
 513  */
 514 static inline bool mod_delayed_work(struct workqueue_struct *wq,
 515                                     struct delayed_work *dwork,
 516                                     unsigned long delay)
 517 {
 518         return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
 519 }
 520
 521 /**
 522  * schedule_work_on - put work task on a specific cpu
 523  * @cpu: cpu to put the work task on
 524  * @work: job to be done
 525  *
 526  * This puts a job on a specific cpu
 527  */
 528 static inline bool schedule_work_on(int cpu, struct work_struct *work)
 529 {
 530         return queue_work_on(cpu, system_wq, work);
 531 }
 532
 533 /**
 534  * schedule_work - put work task in global workqueue
 535  * @work: job to be done
 536  *
 537  * Returns %false if @work was already on the kernel-global workqueue and
 538  * %true otherwise.
 539  *
 540  * This puts a job in the kernel-global workqueue if it was not already
 541  * queued and leaves it in the same position on the kernel-global
 542  * workqueue otherwise.
 543  */
 544 static inline bool schedule_work(struct work_struct *work)
 545 {
 546         return queue_work(system_wq, work);
 547 }
 548
 549 /**
 550  * flush_scheduled_work - ensure that any scheduled work has run to completion.
 551  *
 552  * Forces execution of the kernel-global workqueue and blocks until its
 553  * completion.
 554  *
 555  * Think twice before calling this function!  It's very easy to get into
 556  * trouble if you don't take great care.  Either of the following situations
 557  * will lead to deadlock:
 558  *
 559  *      One of the work items currently on the workqueue needs to acquire
 560  *      a lock held by your code or its caller.
 561  *
 562  *      Your code is running in the context of a work routine.
 563  *
 564  * They will be detected by lockdep when they occur, but the first might not
 565  * occur very often.  It depends on what work items are on the workqueue and
 566  * what locks they need, which you have no control over.
 567  *
 568  * In most situations flushing the entire workqueue is overkill; you merely
 569  * need to know that a particular work item isn't queued and isn't running.
 570  * In such cases you should use cancel_delayed_work_sync() or
 571  * cancel_work_sync() instead.
 572  */
 573 static inline void flush_scheduled_work(void)
 574 {
 575         flush_workqueue(system_wq);
 576 }
 577
 578 /**
 579  * schedule_delayed_work_on - queue work in global workqueue on CPU after delay
 580  * @cpu: cpu to use
 581  * @dwork: job to be done
 582  * @delay: number of jiffies to wait
 583  *
 584  * After waiting for a given time this puts a job in the kernel-global
 585  * workqueue on the specified CPU.
 586  */
 587 static inline bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork,
 588                                             unsigned long delay)
 589 {
 590         return queue_delayed_work_on(cpu, system_wq, dwork, delay);
 591 }
 592
 593 /**
 594  * schedule_delayed_work - put work task in global workqueue after delay
 595  * @dwork: job to be done
 596  * @delay: number of jiffies to wait or 0 for immediate execution
 597  *
 598  * After waiting for a given time this puts a job in the kernel-global
 599  * workqueue.
 600  */
 601 static inline bool schedule_delayed_work(struct delayed_work *dwork,
 602                                          unsigned long delay)
 603 {
 604         return queue_delayed_work(system_wq, dwork, delay);
 605 }
 606
 607 #ifndef CONFIG_SMP
 608 static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
 609 {
 610         return fn(arg);
 611 }
 612 static inline long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg)
 613 {
 614         return fn(arg);
 615 }
 616 #else
 617 long work_on_cpu(int cpu, long (*fn)(void *), void *arg);
 618 long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg);
 619 #endif /* CONFIG_SMP */
 620
 621 #ifdef CONFIG_FREEZER
 622 extern void freeze_workqueues_begin(void);
 623 extern bool freeze_workqueues_busy(void);
 624 extern void thaw_workqueues(void);
 625 #endif /* CONFIG_FREEZER */
 626
 627 #ifdef CONFIG_SYSFS
 628 int workqueue_sysfs_register(struct workqueue_struct *wq);
 629 #else   /* CONFIG_SYSFS */
 630 static inline int workqueue_sysfs_register(struct workqueue_struct *wq)
 631 { return 0; }
 632 #endif  /* CONFIG_SYSFS */
 633
 634 #ifdef CONFIG_WQ_WATCHDOG
 635 void wq_watchdog_touch(int cpu);
 636 #else   /* CONFIG_WQ_WATCHDOG */
 637 static inline void wq_watchdog_touch(int cpu) { }
 638 #endif  /* CONFIG_WQ_WATCHDOG */
 639
 640 #ifdef CONFIG_SMP
 641 int workqueue_prepare_cpu(unsigned int cpu);
 642 int workqueue_online_cpu(unsigned int cpu);
 643 int workqueue_offline_cpu(unsigned int cpu);
 644 #endif
 645
 646 int __init workqueue_init_early(void);
 647 int __init workqueue_init(void);
 648
 649 #endif