root/include/linux/workqueue.h

INCLUDED FROM

DEFINITIONS

1. to_delayed_work
2. to_rcu_work
3. work_static
4. __init_work
5. destroy_work_on_stack
6. destroy_delayed_work_on_stack
7. work_static
8. __printf
9. queue_delayed_work
10. mod_delayed_work
11. schedule_work_on
12. schedule_work
13. flush_scheduled_work
14. schedule_delayed_work_on
15. schedule_delayed_work
16. work_on_cpu
17. work_on_cpu_safe
18. workqueue_sysfs_register
19. wq_watchdog_touch

   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 #include <linux/rcupdate.h>
  17 
  18 struct workqueue_struct;
  19 
  20 struct work_struct;
  21 typedef void (*work_func_t)(struct work_struct *work);
  22 void delayed_work_timer_fn(struct timer_list *t);
  23 
  24 /*
  25  * The first word is the work queue pointer and the flags rolled into
  26  * one
  27  */
  28 #define work_data_bits(work) ((unsigned long *)(&(work)->data))
  29 
  30 enum {
  31         WORK_STRUCT_PENDING_BIT = 0,    /* work item is pending execution */
  32         WORK_STRUCT_DELAYED_BIT = 1,    /* work item is delayed */
  33         WORK_STRUCT_PWQ_BIT     = 2,    /* data points to pwq */
  34         WORK_STRUCT_LINKED_BIT  = 3,    /* next work is linked to this one */
  35 #ifdef CONFIG_DEBUG_OBJECTS_WORK
  36         WORK_STRUCT_STATIC_BIT  = 4,    /* static initializer (debugobjects) */
  37         WORK_STRUCT_COLOR_SHIFT = 5,    /* color for workqueue flushing */
  38 #else
  39         WORK_STRUCT_COLOR_SHIFT = 4,    /* color for workqueue flushing */
  40 #endif
  41 
  42         WORK_STRUCT_COLOR_BITS  = 4,
  43 
  44         WORK_STRUCT_PENDING     = 1 << WORK_STRUCT_PENDING_BIT,
  45         WORK_STRUCT_DELAYED     = 1 << WORK_STRUCT_DELAYED_BIT,
  46         WORK_STRUCT_PWQ         = 1 << WORK_STRUCT_PWQ_BIT,
  47         WORK_STRUCT_LINKED      = 1 << WORK_STRUCT_LINKED_BIT,
  48 #ifdef CONFIG_DEBUG_OBJECTS_WORK
  49         WORK_STRUCT_STATIC      = 1 << WORK_STRUCT_STATIC_BIT,
  50 #else
  51         WORK_STRUCT_STATIC      = 0,
  52 #endif
  53 
  54         /*
  55          * The last color is no color used for works which don't
  56          * participate in workqueue flushing.
  57          */
  58         WORK_NR_COLORS          = (1 << WORK_STRUCT_COLOR_BITS) - 1,
  59         WORK_NO_COLOR           = WORK_NR_COLORS,
  60 
  61         /* not bound to any CPU, prefer the local CPU */
  62         WORK_CPU_UNBOUND        = NR_CPUS,
  63 
  64         /*
  65          * Reserve 7 bits off of pwq pointer w/ debugobjects turned off.
  66          * This makes pwqs aligned to 256 bytes and allows 15 workqueue
  67          * flush colors.
  68          */
  69         WORK_STRUCT_FLAG_BITS   = WORK_STRUCT_COLOR_SHIFT +
  70                                   WORK_STRUCT_COLOR_BITS,
  71 
  72         /* data contains off-queue information when !WORK_STRUCT_PWQ */
  73         WORK_OFFQ_FLAG_BASE     = WORK_STRUCT_COLOR_SHIFT,
  74 
  75         __WORK_OFFQ_CANCELING   = WORK_OFFQ_FLAG_BASE,
  76         WORK_OFFQ_CANCELING     = (1 << __WORK_OFFQ_CANCELING),
  77 
  78         /*
  79          * When a work item is off queue, its high bits point to the last
  80          * pool it was on.  Cap at 31 bits and use the highest number to
  81          * indicate that no pool is associated.
  82          */
  83         WORK_OFFQ_FLAG_BITS     = 1,
  84         WORK_OFFQ_POOL_SHIFT    = WORK_OFFQ_FLAG_BASE + WORK_OFFQ_FLAG_BITS,
  85         WORK_OFFQ_LEFT          = BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT,
  86         WORK_OFFQ_POOL_BITS     = WORK_OFFQ_LEFT <= 31 ? WORK_OFFQ_LEFT : 31,
  87         WORK_OFFQ_POOL_NONE     = (1LU << WORK_OFFQ_POOL_BITS) - 1,
  88 
  89         /* convenience constants */
  90         WORK_STRUCT_FLAG_MASK   = (1UL << WORK_STRUCT_FLAG_BITS) - 1,
  91         WORK_STRUCT_WQ_DATA_MASK = ~WORK_STRUCT_FLAG_MASK,
  92         WORK_STRUCT_NO_POOL     = (unsigned long)WORK_OFFQ_POOL_NONE << WORK_OFFQ_POOL_SHIFT,
  93 
  94         /* bit mask for work_busy() return values */
  95         WORK_BUSY_PENDING       = 1 << 0,
  96         WORK_BUSY_RUNNING       = 1 << 1,
  97 
  98         /* maximum string length for set_worker_desc() */
  99         WORKER_DESC_LEN         = 24,
 100 };
 101 
 102 struct work_struct {
 103         atomic_long_t data;
 104         struct list_head entry;
 105         work_func_t func;
 106 #ifdef CONFIG_LOCKDEP
 107         struct lockdep_map lockdep_map;
 108 #endif
 109 };
 110 
 111 #define WORK_DATA_INIT()        ATOMIC_LONG_INIT((unsigned long)WORK_STRUCT_NO_POOL)
 112 #define WORK_DATA_STATIC_INIT() \
 113         ATOMIC_LONG_INIT((unsigned long)(WORK_STRUCT_NO_POOL | WORK_STRUCT_STATIC))
 114 
 115 struct delayed_work {
 116         struct work_struct work;
 117         struct timer_list timer;
 118 
 119         /* target workqueue and CPU ->timer uses to queue ->work */
 120         struct workqueue_struct *wq;
 121         int cpu;
 122 };
 123 
 124 struct rcu_work {
 125         struct work_struct work;
 126         struct rcu_head rcu;
 127 
 128         /* target workqueue ->rcu uses to queue ->work */
 129         struct workqueue_struct *wq;
 130 };
 131 
 132 /**
 133  * struct workqueue_attrs - A struct for workqueue attributes.
 134  *
 135  * This can be used to change attributes of an unbound workqueue.
 136  */
 137 struct workqueue_attrs {
 138         /**
 139          * @nice: nice level
 140          */
 141         int nice;
 142 
 143         /**
 144          * @cpumask: allowed CPUs
 145          */
 146         cpumask_var_t cpumask;
 147 
 148         /**
 149          * @no_numa: disable NUMA affinity
 150          *
 151          * Unlike other fields, ``no_numa`` isn't a property of a worker_pool. It
 152          * only modifies how :c:func:`apply_workqueue_attrs` select pools and thus
 153          * doesn't participate in pool hash calculations or equality comparisons.
 154          */
 155         bool no_numa;
 156 };
 157 
 158 static inline struct delayed_work *to_delayed_work(struct work_struct *work)
 159 {
 160         return container_of(work, struct delayed_work, work);
 161 }
 162 
 163 static inline struct rcu_work *to_rcu_work(struct work_struct *work)
 164 {
 165         return container_of(work, struct rcu_work, work);
 166 }
 167 
 168 struct execute_work {
 169         struct work_struct work;
 170 };
 171 
 172 #ifdef CONFIG_LOCKDEP
 173 /*
 174  * NB: because we have to copy the lockdep_map, setting _key
 175  * here is required, otherwise it could get initialised to the
 176  * copy of the lockdep_map!
 177  */
 178 #define __WORK_INIT_LOCKDEP_MAP(n, k) \
 179         .lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k),
 180 #else
 181 #define __WORK_INIT_LOCKDEP_MAP(n, k)
 182 #endif
 183 
 184 #define __WORK_INITIALIZER(n, f) {                                      \
 185         .data = WORK_DATA_STATIC_INIT(),                                \
 186         .entry  = { &(n).entry, &(n).entry },                           \
 187         .func = (f),                                                    \
 188         __WORK_INIT_LOCKDEP_MAP(#n, &(n))                               \
 189         }
 190 
 191 #define __DELAYED_WORK_INITIALIZER(n, f, tflags) {                      \
 192         .work = __WORK_INITIALIZER((n).work, (f)),                      \
 193         .timer = __TIMER_INITIALIZER(delayed_work_timer_fn,\
 194                                      (tflags) | TIMER_IRQSAFE),         \
 195         }
 196 
 197 #define DECLARE_WORK(n, f)                                              \
 198         struct work_struct n = __WORK_INITIALIZER(n, f)
 199 
 200 #define DECLARE_DELAYED_WORK(n, f)                                      \
 201         struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, 0)
 202 
 203 #define DECLARE_DEFERRABLE_WORK(n, f)                                   \
 204         struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, TIMER_DEFERRABLE)
 205 
 206 #ifdef CONFIG_DEBUG_OBJECTS_WORK
 207 extern void __init_work(struct work_struct *work, int onstack);
 208 extern void destroy_work_on_stack(struct work_struct *work);
 209 extern void destroy_delayed_work_on_stack(struct delayed_work *work);
 210 static inline unsigned int work_static(struct work_struct *work)
 211 {
 212         return *work_data_bits(work) & WORK_STRUCT_STATIC;
 213 }
 214 #else
 215 static inline void __init_work(struct work_struct *work, int onstack) { }
 216 static inline void destroy_work_on_stack(struct work_struct *work) { }
 217 static inline void destroy_delayed_work_on_stack(struct delayed_work *work) { }
 218 static inline unsigned int work_static(struct work_struct *work) { return 0; }
 219 #endif
 220 
 221 /*
 222  * initialize all of a work item in one go
 223  *
 224  * NOTE! No point in using "atomic_long_set()": using a direct
 225  * assignment of the work data initializer allows the compiler
 226  * to generate better code.
 227  */
 228 #ifdef CONFIG_LOCKDEP
 229 #define __INIT_WORK(_work, _func, _onstack)                             \
 230         do {                                                            \
 231                 static struct lock_class_key __key;                     \
 232                                                                         \
 233                 __init_work((_work), _onstack);                         \
 234                 (_work)->data = (atomic_long_t) WORK_DATA_INIT();       \
 235                 lockdep_init_map(&(_work)->lockdep_map, "(work_completion)"#_work, &__key, 0); \
 236                 INIT_LIST_HEAD(&(_work)->entry);                        \
 237                 (_work)->func = (_func);                                \
 238         } while (0)
 239 #else
 240 #define __INIT_WORK(_work, _func, _onstack)                             \
 241         do {                                                            \
 242                 __init_work((_work), _onstack);                         \
 243                 (_work)->data = (atomic_long_t) WORK_DATA_INIT();       \
 244                 INIT_LIST_HEAD(&(_work)->entry);                        \
 245                 (_work)->func = (_func);                                \
 246         } while (0)
 247 #endif
 248 
 249 #define INIT_WORK(_work, _func)                                         \
 250         __INIT_WORK((_work), (_func), 0)
 251 
 252 #define INIT_WORK_ONSTACK(_work, _func)                                 \
 253         __INIT_WORK((_work), (_func), 1)
 254 
 255 #define __INIT_DELAYED_WORK(_work, _func, _tflags)                      \
 256         do {                                                            \
 257                 INIT_WORK(&(_work)->work, (_func));                     \
 258                 __init_timer(&(_work)->timer,                           \
 259                              delayed_work_timer_fn,                     \
 260                              (_tflags) | TIMER_IRQSAFE);                \
 261         } while (0)
 262 
 263 #define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags)              \
 264         do {                                                            \
 265                 INIT_WORK_ONSTACK(&(_work)->work, (_func));             \
 266                 __init_timer_on_stack(&(_work)->timer,                  \
 267                                       delayed_work_timer_fn,            \
 268                                       (_tflags) | TIMER_IRQSAFE);       \
 269         } while (0)
 270 
 271 #define INIT_DELAYED_WORK(_work, _func)                                 \
 272         __INIT_DELAYED_WORK(_work, _func, 0)
 273 
 274 #define INIT_DELAYED_WORK_ONSTACK(_work, _func)                         \
 275         __INIT_DELAYED_WORK_ONSTACK(_work, _func, 0)
 276 
 277 #define INIT_DEFERRABLE_WORK(_work, _func)                              \
 278         __INIT_DELAYED_WORK(_work, _func, TIMER_DEFERRABLE)
 279 
 280 #define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func)                      \
 281         __INIT_DELAYED_WORK_ONSTACK(_work, _func, TIMER_DEFERRABLE)
 282 
 283 #define INIT_RCU_WORK(_work, _func)                                     \
 284         INIT_WORK(&(_work)->work, (_func))
 285 
 286 #define INIT_RCU_WORK_ONSTACK(_work, _func)                             \
 287         INIT_WORK_ONSTACK(&(_work)->work, (_func))
 288 
 289 /**
 290  * work_pending - Find out whether a work item is currently pending
 291  * @work: The work item in question
 292  */
 293 #define work_pending(work) \
 294         test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
 295 
 296 /**
 297  * delayed_work_pending - Find out whether a delayable work item is currently
 298  * pending
 299  * @w: The work item in question
 300  */
 301 #define delayed_work_pending(w) \
 302         work_pending(&(w)->work)
 303 
 304 /*
 305  * Workqueue flags and constants.  For details, please refer to
 306  * Documentation/core-api/workqueue.rst.
 307  */
 308 enum {
 309         WQ_UNBOUND              = 1 << 1, /* not bound to any cpu */
 310         WQ_FREEZABLE            = 1 << 2, /* freeze during suspend */
 311         WQ_MEM_RECLAIM          = 1 << 3, /* may be used for memory reclaim */
 312         WQ_HIGHPRI              = 1 << 4, /* high priority */
 313         WQ_CPU_INTENSIVE        = 1 << 5, /* cpu intensive workqueue */
 314         WQ_SYSFS                = 1 << 6, /* visible in sysfs, see wq_sysfs_register() */
 315 
 316         /*
 317          * Per-cpu workqueues are generally preferred because they tend to
 318          * show better performance thanks to cache locality.  Per-cpu
 319          * workqueues exclude the scheduler from choosing the CPU to
 320          * execute the worker threads, which has an unfortunate side effect
 321          * of increasing power consumption.
 322          *
 323          * The scheduler considers a CPU idle if it doesn't have any task
 324          * to execute and tries to keep idle cores idle to conserve power;
 325          * however, for example, a per-cpu work item scheduled from an
 326          * interrupt handler on an idle CPU will force the scheduler to
 327          * excute the work item on that CPU breaking the idleness, which in
 328          * turn may lead to more scheduling choices which are sub-optimal
 329          * in terms of power consumption.
 330          *
 331          * Workqueues marked with WQ_POWER_EFFICIENT are per-cpu by default
 332          * but become unbound if workqueue.power_efficient kernel param is
 333          * specified.  Per-cpu workqueues which are identified to
 334          * contribute significantly to power-consumption are identified and
 335          * marked with this flag and enabling the power_efficient mode
 336          * leads to noticeable power saving at the cost of small
 337          * performance disadvantage.
 338          *
 339          * http://thread.gmane.org/gmane.linux.kernel/1480396
 340          */
 341         WQ_POWER_EFFICIENT      = 1 << 7,
 342 
 343         __WQ_DRAINING           = 1 << 16, /* internal: workqueue is draining */
 344         __WQ_ORDERED            = 1 << 17, /* internal: workqueue is ordered */
 345         __WQ_LEGACY             = 1 << 18, /* internal: create*_workqueue() */
 346         __WQ_ORDERED_EXPLICIT   = 1 << 19, /* internal: alloc_ordered_workqueue() */
 347 
 348         WQ_MAX_ACTIVE           = 512,    /* I like 512, better ideas? */
 349         WQ_MAX_UNBOUND_PER_CPU  = 4,      /* 4 * #cpus for unbound wq */
 350         WQ_DFL_ACTIVE           = WQ_MAX_ACTIVE / 2,
 351 };
 352 
 353 /* unbound wq's aren't per-cpu, scale max_active according to #cpus */
 354 #define WQ_UNBOUND_MAX_ACTIVE   \
 355         max_t(int, WQ_MAX_ACTIVE, num_possible_cpus() * WQ_MAX_UNBOUND_PER_CPU)
 356 
 357 /*
 358  * System-wide workqueues which are always present.
 359  *
 360  * system_wq is the one used by schedule[_delayed]_work[_on]().
 361  * Multi-CPU multi-threaded.  There are users which expect relatively
 362  * short queue flush time.  Don't queue works which can run for too
 363  * long.
 364  *
 365  * system_highpri_wq is similar to system_wq but for work items which
 366  * require WQ_HIGHPRI.
 367  *
 368  * system_long_wq is similar to system_wq but may host long running
 369  * works.  Queue flushing might take relatively long.
 370  *
 371  * system_unbound_wq is unbound workqueue.  Workers are not bound to
 372  * any specific CPU, not concurrency managed, and all queued works are
 373  * executed immediately as long as max_active limit is not reached and
 374  * resources are available.
 375  *
 376  * system_freezable_wq is equivalent to system_wq except that it's
 377  * freezable.
 378  *
 379  * *_power_efficient_wq are inclined towards saving power and converted
 380  * into WQ_UNBOUND variants if 'wq_power_efficient' is enabled; otherwise,
 381  * they are same as their non-power-efficient counterparts - e.g.
 382  * system_power_efficient_wq is identical to system_wq if
 383  * 'wq_power_efficient' is disabled.  See WQ_POWER_EFFICIENT for more info.
 384  */
 385 extern struct workqueue_struct *system_wq;
 386 extern struct workqueue_struct *system_highpri_wq;
 387 extern struct workqueue_struct *system_long_wq;
 388 extern struct workqueue_struct *system_unbound_wq;
 389 extern struct workqueue_struct *system_freezable_wq;
 390 extern struct workqueue_struct *system_power_efficient_wq;
 391 extern struct workqueue_struct *system_freezable_power_efficient_wq;
 392 
 393 /**
 394  * alloc_workqueue - allocate a workqueue
 395  * @fmt: printf format for the name of the workqueue
 396  * @flags: WQ_* flags
 397  * @max_active: max in-flight work items, 0 for default
 398  * remaining args: args for @fmt
 399  *
 400  * Allocate a workqueue with the specified parameters.  For detailed
 401  * information on WQ_* flags, please refer to
 402  * Documentation/core-api/workqueue.rst.
 403  *
 404  * RETURNS:
 405  * Pointer to the allocated workqueue on success, %NULL on failure.
 406  */
 407 struct workqueue_struct *alloc_workqueue(const char *fmt,
 408                                          unsigned int flags,
 409                                          int max_active, ...);
 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(void);
 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_work_node(int node, struct workqueue_struct *wq,
 447                             struct work_struct *work);
 448 extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
 449                         struct delayed_work *work, unsigned long delay);
 450 extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
 451                         struct delayed_work *dwork, unsigned long delay);
 452 extern bool queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork);
 453 
 454 extern void flush_workqueue(struct workqueue_struct *wq);
 455 extern void drain_workqueue(struct workqueue_struct *wq);
 456 
 457 extern int schedule_on_each_cpu(work_func_t func);
 458 
 459 int execute_in_process_context(work_func_t fn, struct execute_work *);
 460 
 461 extern bool flush_work(struct work_struct *work);
 462 extern bool cancel_work_sync(struct work_struct *work);
 463 
 464 extern bool flush_delayed_work(struct delayed_work *dwork);
 465 extern bool cancel_delayed_work(struct delayed_work *dwork);
 466 extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
 467 
 468 extern bool flush_rcu_work(struct rcu_work *rwork);
 469 
 470 extern void workqueue_set_max_active(struct workqueue_struct *wq,
 471                                      int max_active);
 472 extern struct work_struct *current_work(void);
 473 extern bool current_is_workqueue_rescuer(void);
 474 extern bool workqueue_congested(int cpu, struct workqueue_struct *wq);
 475 extern unsigned int work_busy(struct work_struct *work);
 476 extern __printf(1, 2) void set_worker_desc(const char *fmt, ...);
 477 extern void print_worker_info(const char *log_lvl, struct task_struct *task);
 478 extern void show_workqueue_state(void);
 479 extern void wq_worker_comm(char *buf, size_t size, struct task_struct *task);
 480 
 481 /**
 482  * queue_work - queue work on a workqueue
 483  * @wq: workqueue to use
 484  * @work: work to queue
 485  *
 486  * Returns %false if @work was already on a queue, %true otherwise.
 487  *
 488  * We queue the work to the CPU on which it was submitted, but if the CPU dies
 489  * it can be processed by another CPU.
 490  */
 491 static inline bool queue_work(struct workqueue_struct *wq,
 492                               struct work_struct *work)
 493 {
 494         return queue_work_on(WORK_CPU_UNBOUND, wq, work);
 495 }
 496 
 497 /**
 498  * queue_delayed_work - queue work on a workqueue after delay
 499  * @wq: workqueue to use
 500  * @dwork: delayable work to queue
 501  * @delay: number of jiffies to wait before queueing
 502  *
 503  * Equivalent to queue_delayed_work_on() but tries to use the local CPU.
 504  */
 505 static inline bool queue_delayed_work(struct workqueue_struct *wq,
 506                                       struct delayed_work *dwork,
 507                                       unsigned long delay)
 508 {
 509         return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
 510 }
 511 
 512 /**
 513  * mod_delayed_work - modify delay of or queue a delayed work
 514  * @wq: workqueue to use
 515  * @dwork: work to queue
 516  * @delay: number of jiffies to wait before queueing
 517  *
 518  * mod_delayed_work_on() on local CPU.
 519  */
 520 static inline bool mod_delayed_work(struct workqueue_struct *wq,
 521                                     struct delayed_work *dwork,
 522                                     unsigned long delay)
 523 {
 524         return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
 525 }
 526 
 527 /**
 528  * schedule_work_on - put work task on a specific cpu
 529  * @cpu: cpu to put the work task on
 530  * @work: job to be done
 531  *
 532  * This puts a job on a specific cpu
 533  */
 534 static inline bool schedule_work_on(int cpu, struct work_struct *work)
 535 {
 536         return queue_work_on(cpu, system_wq, work);
 537 }
 538 
 539 /**
 540  * schedule_work - put work task in global workqueue
 541  * @work: job to be done
 542  *
 543  * Returns %false if @work was already on the kernel-global workqueue and
 544  * %true otherwise.
 545  *
 546  * This puts a job in the kernel-global workqueue if it was not already
 547  * queued and leaves it in the same position on the kernel-global
 548  * workqueue otherwise.
 549  */
 550 static inline bool schedule_work(struct work_struct *work)
 551 {
 552         return queue_work(system_wq, work);
 553 }
 554 
 555 /**
 556  * flush_scheduled_work - ensure that any scheduled work has run to completion.
 557  *
 558  * Forces execution of the kernel-global workqueue and blocks until its
 559  * completion.
 560  *
 561  * Think twice before calling this function!  It's very easy to get into
 562  * trouble if you don't take great care.  Either of the following situations
 563  * will lead to deadlock:
 564  *
 565  *      One of the work items currently on the workqueue needs to acquire
 566  *      a lock held by your code or its caller.
 567  *
 568  *      Your code is running in the context of a work routine.
 569  *
 570  * They will be detected by lockdep when they occur, but the first might not
 571  * occur very often.  It depends on what work items are on the workqueue and
 572  * what locks they need, which you have no control over.
 573  *
 574  * In most situations flushing the entire workqueue is overkill; you merely
 575  * need to know that a particular work item isn't queued and isn't running.
 576  * In such cases you should use cancel_delayed_work_sync() or
 577  * cancel_work_sync() instead.
 578  */
 579 static inline void flush_scheduled_work(void)
 580 {
 581         flush_workqueue(system_wq);
 582 }
 583 
 584 /**
 585  * schedule_delayed_work_on - queue work in global workqueue on CPU after delay
 586  * @cpu: cpu to use
 587  * @dwork: job to be done
 588  * @delay: number of jiffies to wait
 589  *
 590  * After waiting for a given time this puts a job in the kernel-global
 591  * workqueue on the specified CPU.
 592  */
 593 static inline bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork,
 594                                             unsigned long delay)
 595 {
 596         return queue_delayed_work_on(cpu, system_wq, dwork, delay);
 597 }
 598 
 599 /**
 600  * schedule_delayed_work - put work task in global workqueue after delay
 601  * @dwork: job to be done
 602  * @delay: number of jiffies to wait or 0 for immediate execution
 603  *
 604  * After waiting for a given time this puts a job in the kernel-global
 605  * workqueue.
 606  */
 607 static inline bool schedule_delayed_work(struct delayed_work *dwork,
 608                                          unsigned long delay)
 609 {
 610         return queue_delayed_work(system_wq, dwork, delay);
 611 }
 612 
 613 #ifndef CONFIG_SMP
 614 static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
 615 {
 616         return fn(arg);
 617 }
 618 static inline long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg)
 619 {
 620         return fn(arg);
 621 }
 622 #else
 623 long work_on_cpu(int cpu, long (*fn)(void *), void *arg);
 624 long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg);
 625 #endif /* CONFIG_SMP */
 626 
 627 #ifdef CONFIG_FREEZER
 628 extern void freeze_workqueues_begin(void);
 629 extern bool freeze_workqueues_busy(void);
 630 extern void thaw_workqueues(void);
 631 #endif /* CONFIG_FREEZER */
 632 
 633 #ifdef CONFIG_SYSFS
 634 int workqueue_sysfs_register(struct workqueue_struct *wq);
 635 #else   /* CONFIG_SYSFS */
 636 static inline int workqueue_sysfs_register(struct workqueue_struct *wq)
 637 { return 0; }
 638 #endif  /* CONFIG_SYSFS */
 639 
 640 #ifdef CONFIG_WQ_WATCHDOG
 641 void wq_watchdog_touch(int cpu);
 642 #else   /* CONFIG_WQ_WATCHDOG */
 643 static inline void wq_watchdog_touch(int cpu) { }
 644 #endif  /* CONFIG_WQ_WATCHDOG */
 645 
 646 #ifdef CONFIG_SMP
 647 int workqueue_prepare_cpu(unsigned int cpu);
 648 int workqueue_online_cpu(unsigned int cpu);
 649 int workqueue_offline_cpu(unsigned int cpu);
 650 #endif
 651 
 652 int __init workqueue_init_early(void);
 653 int __init workqueue_init(void);
 654 
 655 #endif