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/alloc_tag.h>
  10 #include <linux/timer.h>
  11 #include <linux/linkage.h>
  12 #include <linux/bitops.h>
  13 #include <linux/lockdep.h>
  14 #include <linux/threads.h>
  15 #include <linux/atomic.h>
  16 #include <linux/cpumask_types.h>
  17 #include <linux/rcupdate.h>
  18 #include <linux/workqueue_types.h>
  19
  20 /*
  21  * The first word is the work queue pointer and the flags rolled into
  22  * one
  23  */
  24 #define work_data_bits(work) ((unsigned long *)(&(work)->data))
  25
  26 enum work_bits {
  27         WORK_STRUCT_PENDING_BIT = 0,    /* work item is pending execution */
  28         WORK_STRUCT_INACTIVE_BIT,       /* work item is inactive */
  29         WORK_STRUCT_PWQ_BIT,            /* data points to pwq */
  30         WORK_STRUCT_LINKED_BIT,         /* next work is linked to this one */
  31 #ifdef CONFIG_DEBUG_OBJECTS_WORK
  32         WORK_STRUCT_STATIC_BIT,         /* static initializer (debugobjects) */
  33 #endif
  34         WORK_STRUCT_FLAG_BITS,
  35
  36         /* color for workqueue flushing */
  37         WORK_STRUCT_COLOR_SHIFT = WORK_STRUCT_FLAG_BITS,
  38         WORK_STRUCT_COLOR_BITS  = 4,
  39
  40         /*
  41          * When WORK_STRUCT_PWQ is set, reserve 8 bits off of pwq pointer w/
  42          * debugobjects turned off. This makes pwqs aligned to 256 bytes (512
  43          * bytes w/ DEBUG_OBJECTS_WORK) and allows 16 workqueue flush colors.
  44          *
  45          * MSB
  46          * [ pwq pointer ] [ flush color ] [ STRUCT flags ]
  47          *                     4 bits        4 or 5 bits
  48          */
  49         WORK_STRUCT_PWQ_SHIFT   = WORK_STRUCT_COLOR_SHIFT + WORK_STRUCT_COLOR_BITS,
  50
  51         /*
  52          * data contains off-queue information when !WORK_STRUCT_PWQ.
  53          *
  54          * MSB
  55          * [ pool ID ] [ disable depth ] [ OFFQ flags ] [ STRUCT flags ]
  56          *                  16 bits          1 bit        4 or 5 bits
  57          */
  58         WORK_OFFQ_FLAG_SHIFT    = WORK_STRUCT_FLAG_BITS,
  59         WORK_OFFQ_BH_BIT        = WORK_OFFQ_FLAG_SHIFT,
  60         WORK_OFFQ_FLAG_END,
  61         WORK_OFFQ_FLAG_BITS     = WORK_OFFQ_FLAG_END - WORK_OFFQ_FLAG_SHIFT,
  62
  63         WORK_OFFQ_DISABLE_SHIFT = WORK_OFFQ_FLAG_SHIFT + WORK_OFFQ_FLAG_BITS,
  64         WORK_OFFQ_DISABLE_BITS  = 16,
  65
  66         /*
  67          * When a work item is off queue, the high bits encode off-queue flags
  68          * and the last pool it was on. Cap pool ID to 31 bits and use the
  69          * highest number to indicate that no pool is associated.
  70          */
  71         WORK_OFFQ_POOL_SHIFT    = WORK_OFFQ_DISABLE_SHIFT + WORK_OFFQ_DISABLE_BITS,
  72         WORK_OFFQ_LEFT          = BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT,
  73         WORK_OFFQ_POOL_BITS     = WORK_OFFQ_LEFT <= 31 ? WORK_OFFQ_LEFT : 31,
  74 };
  75
  76 enum work_flags {
  77         WORK_STRUCT_PENDING     = 1 << WORK_STRUCT_PENDING_BIT,
  78         WORK_STRUCT_INACTIVE    = 1 << WORK_STRUCT_INACTIVE_BIT,
  79         WORK_STRUCT_PWQ         = 1 << WORK_STRUCT_PWQ_BIT,
  80         WORK_STRUCT_LINKED      = 1 << WORK_STRUCT_LINKED_BIT,
  81 #ifdef CONFIG_DEBUG_OBJECTS_WORK
  82         WORK_STRUCT_STATIC      = 1 << WORK_STRUCT_STATIC_BIT,
  83 #else
  84         WORK_STRUCT_STATIC      = 0,
  85 #endif
  86 };
  87
  88 enum wq_misc_consts {
  89         WORK_NR_COLORS          = (1 << WORK_STRUCT_COLOR_BITS),
  90
  91         /* not bound to any CPU, prefer the local CPU */
  92         WORK_CPU_UNBOUND        = NR_CPUS,
  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         = 32,
 100 };
 101
 102 /* Convenience constants - of type 'unsigned long', not 'enum'! */
 103 #define WORK_OFFQ_BH            (1ul << WORK_OFFQ_BH_BIT)
 104 #define WORK_OFFQ_FLAG_MASK     (((1ul << WORK_OFFQ_FLAG_BITS) - 1) << WORK_OFFQ_FLAG_SHIFT)
 105 #define WORK_OFFQ_DISABLE_MASK  (((1ul << WORK_OFFQ_DISABLE_BITS) - 1) << WORK_OFFQ_DISABLE_SHIFT)
 106 #define WORK_OFFQ_POOL_NONE     ((1ul << WORK_OFFQ_POOL_BITS) - 1)
 107 #define WORK_STRUCT_NO_POOL     (WORK_OFFQ_POOL_NONE << WORK_OFFQ_POOL_SHIFT)
 108 #define WORK_STRUCT_PWQ_MASK    (~((1ul << WORK_STRUCT_PWQ_SHIFT) - 1))
 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 struct rcu_work {
 124         struct work_struct work;
 125         struct rcu_head rcu;
 126
 127         /* target workqueue ->rcu uses to queue ->work */
 128         struct workqueue_struct *wq;
 129 };
 130
 131 enum wq_affn_scope {
 132         WQ_AFFN_DFL,                    /* use system default */
 133         WQ_AFFN_CPU,                    /* one pod per CPU */
 134         WQ_AFFN_SMT,                    /* one pod poer SMT */
 135         WQ_AFFN_CACHE,                  /* one pod per LLC */
 136         WQ_AFFN_NUMA,                   /* one pod per NUMA node */
 137         WQ_AFFN_SYSTEM,                 /* one pod across the whole system */
 138
 139         WQ_AFFN_NR_TYPES,
 140 };
 141
 142 /**
 143  * struct workqueue_attrs - A struct for workqueue attributes.
 144  *
 145  * This can be used to change attributes of an unbound workqueue.
 146  */
 147 struct workqueue_attrs {
 148         /**
 149          * @nice: nice level
 150          */
 151         int nice;
 152
 153         /**
 154          * @cpumask: allowed CPUs
 155          *
 156          * Work items in this workqueue are affine to these CPUs and not allowed
 157          * to execute on other CPUs. A pool serving a workqueue must have the
 158          * same @cpumask.
 159          */
 160         cpumask_var_t cpumask;
 161
 162         /**
 163          * @__pod_cpumask: internal attribute used to create per-pod pools
 164          *
 165          * Internal use only.
 166          *
 167          * Per-pod unbound worker pools are used to improve locality. Always a
 168          * subset of ->cpumask. A workqueue can be associated with multiple
 169          * worker pools with disjoint @__pod_cpumask's. Whether the enforcement
 170          * of a pool's @__pod_cpumask is strict depends on @affn_strict.
 171          */
 172         cpumask_var_t __pod_cpumask;
 173
 174         /**
 175          * @affn_strict: affinity scope is strict
 176          *
 177          * If clear, workqueue will make a best-effort attempt at starting the
 178          * worker inside @__pod_cpumask but the scheduler is free to migrate it
 179          * outside.
 180          *
 181          * If set, workers are only allowed to run inside @__pod_cpumask.
 182          */
 183         bool affn_strict;
 184
 185         /*
 186          * Below fields aren't properties of a worker_pool. They only modify how
 187          * :c:func:`apply_workqueue_attrs` select pools and thus don't
 188          * participate in pool hash calculations or equality comparisons.
 189          *
 190          * If @affn_strict is set, @cpumask isn't a property of a worker_pool
 191          * either.
 192          */
 193
 194         /**
 195          * @affn_scope: unbound CPU affinity scope
 196          *
 197          * CPU pods are used to improve execution locality of unbound work
 198          * items. There are multiple pod types, one for each wq_affn_scope, and
 199          * every CPU in the system belongs to one pod in every pod type. CPUs
 200          * that belong to the same pod share the worker pool. For example,
 201          * selecting %WQ_AFFN_NUMA makes the workqueue use a separate worker
 202          * pool for each NUMA node.
 203          */
 204         enum wq_affn_scope affn_scope;
 205
 206         /**
 207          * @ordered: work items must be executed one by one in queueing order
 208          */
 209         bool ordered;
 210 };
 211
 212 static inline struct delayed_work *to_delayed_work(struct work_struct *work)
 213 {
 214         return container_of(work, struct delayed_work, work);
 215 }
 216
 217 static inline struct rcu_work *to_rcu_work(struct work_struct *work)
 218 {
 219         return container_of(work, struct rcu_work, work);
 220 }
 221
 222 struct execute_work {
 223         struct work_struct work;
 224 };
 225
 226 #ifdef CONFIG_LOCKDEP
 227 /*
 228  * NB: because we have to copy the lockdep_map, setting _key
 229  * here is required, otherwise it could get initialised to the
 230  * copy of the lockdep_map!
 231  */
 232 #define __WORK_INIT_LOCKDEP_MAP(n, k) \
 233         .lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k),
 234 #else
 235 #define __WORK_INIT_LOCKDEP_MAP(n, k)
 236 #endif
 237
 238 #define __WORK_INITIALIZER(n, f) {                                      \
 239         .data = WORK_DATA_STATIC_INIT(),                                \
 240         .entry  = { &(n).entry, &(n).entry },                           \
 241         .func = (f),                                                    \
 242         __WORK_INIT_LOCKDEP_MAP(#n, &(n))                               \
 243         }
 244
 245 #define __DELAYED_WORK_INITIALIZER(n, f, tflags) {                      \
 246         .work = __WORK_INITIALIZER((n).work, (f)),                      \
 247         .timer = __TIMER_INITIALIZER(delayed_work_timer_fn,\
 248                                      (tflags) | TIMER_IRQSAFE),         \
 249         }
 250
 251 #define DECLARE_WORK(n, f)                                              \
 252         struct work_struct n = __WORK_INITIALIZER(n, f)
 253
 254 #define DECLARE_DELAYED_WORK(n, f)                                      \
 255         struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, 0)
 256
 257 #define DECLARE_DEFERRABLE_WORK(n, f)                                   \
 258         struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, TIMER_DEFERRABLE)
 259
 260 #ifdef CONFIG_DEBUG_OBJECTS_WORK
 261 extern void __init_work(struct work_struct *work, int onstack);
 262 extern void destroy_work_on_stack(struct work_struct *work);
 263 extern void destroy_delayed_work_on_stack(struct delayed_work *work);
 264 static inline unsigned int work_static(struct work_struct *work)
 265 {
 266         return *work_data_bits(work) & WORK_STRUCT_STATIC;
 267 }
 268 #else
 269 static inline void __init_work(struct work_struct *work, int onstack) { }
 270 static inline void destroy_work_on_stack(struct work_struct *work) { }
 271 static inline void destroy_delayed_work_on_stack(struct delayed_work *work) { }
 272 static inline unsigned int work_static(struct work_struct *work) { return 0; }
 273 #endif
 274
 275 /*
 276  * initialize all of a work item in one go
 277  *
 278  * NOTE! No point in using "atomic_long_set()": using a direct
 279  * assignment of the work data initializer allows the compiler
 280  * to generate better code.
 281  */
 282 #ifdef CONFIG_LOCKDEP
 283 #define __INIT_WORK_KEY(_work, _func, _onstack, _key)                   \
 284         do {                                                            \
 285                 __init_work((_work), _onstack);                         \
 286                 (_work)->data = (atomic_long_t) WORK_DATA_INIT();       \
 287                 lockdep_init_map(&(_work)->lockdep_map, "(work_completion)"#_work, (_key), 0); \
 288                 INIT_LIST_HEAD(&(_work)->entry);                        \
 289                 (_work)->func = (_func);                                \
 290         } while (0)
 291 #else
 292 #define __INIT_WORK_KEY(_work, _func, _onstack, _key)                   \
 293         do {                                                            \
 294                 __init_work((_work), _onstack);                         \
 295                 (_work)->data = (atomic_long_t) WORK_DATA_INIT();       \
 296                 INIT_LIST_HEAD(&(_work)->entry);                        \
 297                 (_work)->func = (_func);                                \
 298         } while (0)
 299 #endif
 300
 301 #define __INIT_WORK(_work, _func, _onstack)                             \
 302         do {                                                            \
 303                 static __maybe_unused struct lock_class_key __key;      \
 304                                                                         \
 305                 __INIT_WORK_KEY(_work, _func, _onstack, &__key);        \
 306         } while (0)
 307
 308 #define INIT_WORK(_work, _func)                                         \
 309         __INIT_WORK((_work), (_func), 0)
 310
 311 #define INIT_WORK_ONSTACK(_work, _func)                                 \
 312         __INIT_WORK((_work), (_func), 1)
 313
 314 #define INIT_WORK_ONSTACK_KEY(_work, _func, _key)                       \
 315         __INIT_WORK_KEY((_work), (_func), 1, _key)
 316
 317 #define __INIT_DELAYED_WORK(_work, _func, _tflags)                      \
 318         do {                                                            \
 319                 INIT_WORK(&(_work)->work, (_func));                     \
 320                 __timer_init(&(_work)->timer,                           \
 321                              delayed_work_timer_fn,                     \
 322                              (_tflags) | TIMER_IRQSAFE);                \
 323         } while (0)
 324
 325 #define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags)              \
 326         do {                                                            \
 327                 INIT_WORK_ONSTACK(&(_work)->work, (_func));             \
 328                 __timer_init_on_stack(&(_work)->timer,                  \
 329                                       delayed_work_timer_fn,            \
 330                                       (_tflags) | TIMER_IRQSAFE);       \
 331         } while (0)
 332
 333 #define INIT_DELAYED_WORK(_work, _func)                                 \
 334         __INIT_DELAYED_WORK(_work, _func, 0)
 335
 336 #define INIT_DELAYED_WORK_ONSTACK(_work, _func)                         \
 337         __INIT_DELAYED_WORK_ONSTACK(_work, _func, 0)
 338
 339 #define INIT_DEFERRABLE_WORK(_work, _func)                              \
 340         __INIT_DELAYED_WORK(_work, _func, TIMER_DEFERRABLE)
 341
 342 #define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func)                      \
 343         __INIT_DELAYED_WORK_ONSTACK(_work, _func, TIMER_DEFERRABLE)
 344
 345 #define INIT_RCU_WORK(_work, _func)                                     \
 346         INIT_WORK(&(_work)->work, (_func))
 347
 348 #define INIT_RCU_WORK_ONSTACK(_work, _func)                             \
 349         INIT_WORK_ONSTACK(&(_work)->work, (_func))
 350
 351 /**
 352  * work_pending - Find out whether a work item is currently pending
 353  * @work: The work item in question
 354  */
 355 #define work_pending(work) \
 356         test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
 357
 358 /**
 359  * delayed_work_pending - Find out whether a delayable work item is currently
 360  * pending
 361  * @w: The work item in question
 362  */
 363 #define delayed_work_pending(w) \
 364         work_pending(&(w)->work)
 365
 366 /*
 367  * Workqueue flags and constants.  For details, please refer to
 368  * Documentation/core-api/workqueue.rst.
 369  */
 370 enum wq_flags {
 371         WQ_BH                   = 1 << 0, /* execute in bottom half (softirq) context */
 372         WQ_UNBOUND              = 1 << 1, /* not bound to any cpu */
 373         WQ_FREEZABLE            = 1 << 2, /* freeze during suspend */
 374         WQ_MEM_RECLAIM          = 1 << 3, /* may be used for memory reclaim */
 375         WQ_HIGHPRI              = 1 << 4, /* high priority */
 376         WQ_CPU_INTENSIVE        = 1 << 5, /* cpu intensive workqueue */
 377         WQ_SYSFS                = 1 << 6, /* visible in sysfs, see workqueue_sysfs_register() */
 378
 379         /*
 380          * Per-cpu workqueues are generally preferred because they tend to
 381          * show better performance thanks to cache locality.  Per-cpu
 382          * workqueues exclude the scheduler from choosing the CPU to
 383          * execute the worker threads, which has an unfortunate side effect
 384          * of increasing power consumption.
 385          *
 386          * The scheduler considers a CPU idle if it doesn't have any task
 387          * to execute and tries to keep idle cores idle to conserve power;
 388          * however, for example, a per-cpu work item scheduled from an
 389          * interrupt handler on an idle CPU will force the scheduler to
 390          * execute the work item on that CPU breaking the idleness, which in
 391          * turn may lead to more scheduling choices which are sub-optimal
 392          * in terms of power consumption.
 393          *
 394          * Workqueues marked with WQ_POWER_EFFICIENT are per-cpu by default
 395          * but become unbound if workqueue.power_efficient kernel param is
 396          * specified.  Per-cpu workqueues which are identified to
 397          * contribute significantly to power-consumption are identified and
 398          * marked with this flag and enabling the power_efficient mode
 399          * leads to noticeable power saving at the cost of small
 400          * performance disadvantage.
 401          *
 402          * http://thread.gmane.org/gmane.linux.kernel/1480396
 403          */
 404         WQ_POWER_EFFICIENT      = 1 << 7,
 405         WQ_PERCPU               = 1 << 8, /* bound to a specific cpu */
 406
 407         __WQ_DESTROYING         = 1 << 15, /* internal: workqueue is destroying */
 408         __WQ_DRAINING           = 1 << 16, /* internal: workqueue is draining */
 409         __WQ_ORDERED            = 1 << 17, /* internal: workqueue is ordered */
 410         __WQ_LEGACY             = 1 << 18, /* internal: create*_workqueue() */
 411
 412         /* BH wq only allows the following flags */
 413         __WQ_BH_ALLOWS          = WQ_BH | WQ_HIGHPRI | WQ_PERCPU,
 414 };
 415
 416 enum wq_consts {
 417         WQ_MAX_ACTIVE           = 2048,   /* I like 2048, better ideas? */
 418         WQ_UNBOUND_MAX_ACTIVE   = WQ_MAX_ACTIVE,
 419         WQ_DFL_ACTIVE           = WQ_MAX_ACTIVE / 2,
 420
 421         /*
 422          * Per-node default cap on min_active. Unless explicitly set, min_active
 423          * is set to min(max_active, WQ_DFL_MIN_ACTIVE). For more details, see
 424          * workqueue_struct->min_active definition.
 425          */
 426         WQ_DFL_MIN_ACTIVE       = 8,
 427 };
 428
 429 /*
 430  * System-wide workqueues which are always present.
 431  *
 432  * system_percpu_wq is the one used by schedule[_delayed]_work[_on]().
 433  * Multi-CPU multi-threaded.  There are users which expect relatively
 434  * short queue flush time.  Don't queue works which can run for too
 435  * long.
 436  *
 437  * system_highpri_wq is similar to system_percpu_wq but for work items which
 438  * require WQ_HIGHPRI.
 439  *
 440  * system_long_wq is similar to system_percpu_wq but may host long running
 441  * works.  Queue flushing might take relatively long.
 442  *
 443  * system_dfl_wq is unbound workqueue.  Workers are not bound to
 444  * any specific CPU, not concurrency managed, and all queued works are
 445  * executed immediately as long as max_active limit is not reached and
 446  * resources are available.
 447  *
 448  * system_freezable_wq is equivalent to system_percpu_wq except that it's
 449  * freezable.
 450  *
 451  * *_power_efficient_wq are inclined towards saving power and converted
 452  * into WQ_UNBOUND variants if 'wq_power_efficient' is enabled; otherwise,
 453  * they are same as their non-power-efficient counterparts - e.g.
 454  * system_power_efficient_wq is identical to system_percpu_wq if
 455  * 'wq_power_efficient' is disabled.  See WQ_POWER_EFFICIENT for more info.
 456  *
 457  * system_bh[_highpri]_wq are convenience interface to softirq. BH work items
 458  * are executed in the queueing CPU's BH context in the queueing order.
 459  */
 460 extern struct workqueue_struct *system_wq; /* use system_percpu_wq, this will be removed */
 461 extern struct workqueue_struct *system_percpu_wq;
 462 extern struct workqueue_struct *system_highpri_wq;
 463 extern struct workqueue_struct *system_long_wq;
 464 extern struct workqueue_struct *system_unbound_wq;
 465 extern struct workqueue_struct *system_dfl_wq;
 466 extern struct workqueue_struct *system_freezable_wq;
 467 extern struct workqueue_struct *system_power_efficient_wq;
 468 extern struct workqueue_struct *system_freezable_power_efficient_wq;
 469 extern struct workqueue_struct *system_bh_wq;
 470 extern struct workqueue_struct *system_bh_highpri_wq;
 471
 472 void workqueue_softirq_action(bool highpri);
 473 void workqueue_softirq_dead(unsigned int cpu);
 474
 475 /**
 476  * alloc_workqueue - allocate a workqueue
 477  * @fmt: printf format for the name of the workqueue
 478  * @flags: WQ_* flags
 479  * @max_active: max in-flight work items, 0 for default
 480  * @...: args for @fmt
 481  *
 482  * For a per-cpu workqueue, @max_active limits the number of in-flight work
 483  * items for each CPU. e.g. @max_active of 1 indicates that each CPU can be
 484  * executing at most one work item for the workqueue.
 485  *
 486  * For unbound workqueues, @max_active limits the number of in-flight work items
 487  * for the whole system. e.g. @max_active of 16 indicates that there can be
 488  * at most 16 work items executing for the workqueue in the whole system.
 489  *
 490  * As sharing the same active counter for an unbound workqueue across multiple
 491  * NUMA nodes can be expensive, @max_active is distributed to each NUMA node
 492  * according to the proportion of the number of online CPUs and enforced
 493  * independently.
 494  *
 495  * Depending on online CPU distribution, a node may end up with per-node
 496  * max_active which is significantly lower than @max_active, which can lead to
 497  * deadlocks if the per-node concurrency limit is lower than the maximum number
 498  * of interdependent work items for the workqueue.
 499  *
 500  * To guarantee forward progress regardless of online CPU distribution, the
 501  * concurrency limit on every node is guaranteed to be equal to or greater than
 502  * min_active which is set to min(@max_active, %WQ_DFL_MIN_ACTIVE). This means
 503  * that the sum of per-node max_active's may be larger than @max_active.
 504  *
 505  * For detailed information on %WQ_\* flags, please refer to
 506  * Documentation/core-api/workqueue.rst.
 507  *
 508  * RETURNS:
 509  * Pointer to the allocated workqueue on success, %NULL on failure.
 510  */
 511 __printf(1, 4) struct workqueue_struct *
 512 alloc_workqueue_noprof(const char *fmt, unsigned int flags, int max_active, ...);
 513 #define alloc_workqueue(...)    alloc_hooks(alloc_workqueue_noprof(__VA_ARGS__))
 514
 515 #ifdef CONFIG_LOCKDEP
 516 /**
 517  * alloc_workqueue_lockdep_map - allocate a workqueue with user-defined lockdep_map
 518  * @fmt: printf format for the name of the workqueue
 519  * @flags: WQ_* flags
 520  * @max_active: max in-flight work items, 0 for default
 521  * @lockdep_map: user-defined lockdep_map
 522  * @...: args for @fmt
 523  *
 524  * Same as alloc_workqueue but with the a user-define lockdep_map. Useful for
 525  * workqueues created with the same purpose and to avoid leaking a lockdep_map
 526  * on each workqueue creation.
 527  *
 528  * RETURNS:
 529  * Pointer to the allocated workqueue on success, %NULL on failure.
 530  */
 531 __printf(1, 5) struct workqueue_struct *
 532 alloc_workqueue_lockdep_map(const char *fmt, unsigned int flags, int max_active,
 533                             struct lockdep_map *lockdep_map, ...);
 534
 535 /**
 536  * alloc_ordered_workqueue_lockdep_map - allocate an ordered workqueue with
 537  * user-defined lockdep_map
 538  *
 539  * @fmt: printf format for the name of the workqueue
 540  * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
 541  * @lockdep_map: user-defined lockdep_map
 542  * @args: args for @fmt
 543  *
 544  * Same as alloc_ordered_workqueue but with the a user-define lockdep_map.
 545  * Useful for workqueues created with the same purpose and to avoid leaking a
 546  * lockdep_map on each workqueue creation.
 547  *
 548  * RETURNS:
 549  * Pointer to the allocated workqueue on success, %NULL on failure.
 550  */
 551 #define alloc_ordered_workqueue_lockdep_map(fmt, flags, lockdep_map, args...)   \
 552         alloc_hooks(alloc_workqueue_lockdep_map(fmt, WQ_UNBOUND | __WQ_ORDERED | (flags),\
 553                                                 1, lockdep_map, ##args))
 554 #endif
 555
 556 /**
 557  * alloc_ordered_workqueue - allocate an ordered workqueue
 558  * @fmt: printf format for the name of the workqueue
 559  * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
 560  * @args: args for @fmt
 561  *
 562  * Allocate an ordered workqueue.  An ordered workqueue executes at
 563  * most one work item at any given time in the queued order.  They are
 564  * implemented as unbound workqueues with @max_active of one.
 565  *
 566  * RETURNS:
 567  * Pointer to the allocated workqueue on success, %NULL on failure.
 568  */
 569 #define alloc_ordered_workqueue(fmt, flags, args...)                    \
 570         alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | (flags), 1, ##args)
 571
 572 #define create_workqueue(name)                                          \
 573         alloc_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM | WQ_PERCPU, 1, (name))
 574 #define create_freezable_workqueue(name)                                \
 575         alloc_workqueue("%s", __WQ_LEGACY | WQ_FREEZABLE | WQ_UNBOUND | \
 576                         WQ_MEM_RECLAIM, 1, (name))
 577 #define create_singlethread_workqueue(name)                             \
 578         alloc_ordered_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, name)
 579
 580 #define from_work(var, callback_work, work_fieldname)   \
 581         container_of(callback_work, typeof(*var), work_fieldname)
 582
 583 extern void destroy_workqueue(struct workqueue_struct *wq);
 584
 585 struct workqueue_attrs *alloc_workqueue_attrs_noprof(void);
 586 #define alloc_workqueue_attrs(...)      alloc_hooks(alloc_workqueue_attrs_noprof(__VA_ARGS__))
 587
 588 void free_workqueue_attrs(struct workqueue_attrs *attrs);
 589 int apply_workqueue_attrs(struct workqueue_struct *wq,
 590                           const struct workqueue_attrs *attrs);
 591 extern int workqueue_unbound_housekeeping_update(const struct cpumask *hk);
 592
 593 extern bool queue_work_on(int cpu, struct workqueue_struct *wq,
 594                         struct work_struct *work);
 595 extern bool queue_work_node(int node, struct workqueue_struct *wq,
 596                             struct work_struct *work);
 597 extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
 598                         struct delayed_work *work, unsigned long delay);
 599 extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
 600                         struct delayed_work *dwork, unsigned long delay);
 601 extern bool queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork);
 602
 603 extern void __flush_workqueue(struct workqueue_struct *wq);
 604 extern void drain_workqueue(struct workqueue_struct *wq);
 605
 606 extern int schedule_on_each_cpu(work_func_t func);
 607
 608 int execute_in_process_context(work_func_t fn, struct execute_work *);
 609
 610 extern bool flush_work(struct work_struct *work);
 611 extern bool cancel_work(struct work_struct *work);
 612 extern bool cancel_work_sync(struct work_struct *work);
 613
 614 extern bool flush_delayed_work(struct delayed_work *dwork);
 615 extern bool cancel_delayed_work(struct delayed_work *dwork);
 616 extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
 617
 618 extern bool disable_work(struct work_struct *work);
 619 extern bool disable_work_sync(struct work_struct *work);
 620 extern bool enable_work(struct work_struct *work);
 621
 622 extern bool disable_delayed_work(struct delayed_work *dwork);
 623 extern bool disable_delayed_work_sync(struct delayed_work *dwork);
 624 extern bool enable_delayed_work(struct delayed_work *dwork);
 625
 626 extern bool flush_rcu_work(struct rcu_work *rwork);
 627
 628 extern void workqueue_set_max_active(struct workqueue_struct *wq,
 629                                      int max_active);
 630 extern void workqueue_set_min_active(struct workqueue_struct *wq,
 631                                      int min_active);
 632 extern struct work_struct *current_work(void);
 633 extern bool current_is_workqueue_rescuer(void);
 634 extern bool workqueue_congested(int cpu, struct workqueue_struct *wq);
 635 extern unsigned int work_busy(struct work_struct *work);
 636 extern __printf(1, 2) void set_worker_desc(const char *fmt, ...);
 637 extern void print_worker_info(const char *log_lvl, struct task_struct *task);
 638 extern void show_all_workqueues(void);
 639 extern void show_freezable_workqueues(void);
 640 extern void show_one_workqueue(struct workqueue_struct *wq);
 641 extern void wq_worker_comm(char *buf, size_t size, struct task_struct *task);
 642
 643 /**
 644  * queue_work - queue work on a workqueue
 645  * @wq: workqueue to use
 646  * @work: work to queue
 647  *
 648  * Returns %false if @work was already on a queue, %true otherwise.
 649  *
 650  * We queue the work to the CPU on which it was submitted, but if the CPU dies
 651  * it can be processed by another CPU.
 652  *
 653  * Memory-ordering properties:  If it returns %true, guarantees that all stores
 654  * preceding the call to queue_work() in the program order will be visible from
 655  * the CPU which will execute @work by the time such work executes, e.g.,
 656  *
 657  * { x is initially 0 }
 658  *
 659  *   CPU0                               CPU1
 660  *
 661  *   WRITE_ONCE(x, 1);                  [ @work is being executed ]
 662  *   r0 = queue_work(wq, work);           r1 = READ_ONCE(x);
 663  *
 664  * Forbids: r0 == true && r1 == 0
 665  */
 666 static inline bool queue_work(struct workqueue_struct *wq,
 667                               struct work_struct *work)
 668 {
 669         return queue_work_on(WORK_CPU_UNBOUND, wq, work);
 670 }
 671
 672 /**
 673  * queue_delayed_work - queue work on a workqueue after delay
 674  * @wq: workqueue to use
 675  * @dwork: delayable work to queue
 676  * @delay: number of jiffies to wait before queueing
 677  *
 678  * Equivalent to queue_delayed_work_on() but tries to use the local CPU.
 679  */
 680 static inline bool queue_delayed_work(struct workqueue_struct *wq,
 681                                       struct delayed_work *dwork,
 682                                       unsigned long delay)
 683 {
 684         return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
 685 }
 686
 687 /**
 688  * mod_delayed_work - modify delay of or queue a delayed work
 689  * @wq: workqueue to use
 690  * @dwork: work to queue
 691  * @delay: number of jiffies to wait before queueing
 692  *
 693  * mod_delayed_work_on() on local CPU.
 694  */
 695 static inline bool mod_delayed_work(struct workqueue_struct *wq,
 696                                     struct delayed_work *dwork,
 697                                     unsigned long delay)
 698 {
 699         return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay);
 700 }
 701
 702 /**
 703  * schedule_work_on - put work task on a specific cpu
 704  * @cpu: cpu to put the work task on
 705  * @work: job to be done
 706  *
 707  * This puts a job on a specific cpu
 708  */
 709 static inline bool schedule_work_on(int cpu, struct work_struct *work)
 710 {
 711         return queue_work_on(cpu, system_percpu_wq, work);
 712 }
 713
 714 /**
 715  * schedule_work - put work task in global workqueue
 716  * @work: job to be done
 717  *
 718  * Returns %false if @work was already on the kernel-global workqueue and
 719  * %true otherwise.
 720  *
 721  * This puts a job in the kernel-global workqueue if it was not already
 722  * queued and leaves it in the same position on the kernel-global
 723  * workqueue otherwise.
 724  *
 725  * Shares the same memory-ordering properties of queue_work(), cf. the
 726  * DocBook header of queue_work().
 727  */
 728 static inline bool schedule_work(struct work_struct *work)
 729 {
 730         return queue_work(system_percpu_wq, work);
 731 }
 732
 733 /**
 734  * enable_and_queue_work - Enable and queue a work item on a specific workqueue
 735  * @wq: The target workqueue
 736  * @work: The work item to be enabled and queued
 737  *
 738  * This function combines the operations of enable_work() and queue_work(),
 739  * providing a convenient way to enable and queue a work item in a single call.
 740  * It invokes enable_work() on @work and then queues it if the disable depth
 741  * reached 0. Returns %true if the disable depth reached 0 and @work is queued,
 742  * and %false otherwise.
 743  *
 744  * Note that @work is always queued when disable depth reaches zero. If the
 745  * desired behavior is queueing only if certain events took place while @work is
 746  * disabled, the user should implement the necessary state tracking and perform
 747  * explicit conditional queueing after enable_work().
 748  */
 749 static inline bool enable_and_queue_work(struct workqueue_struct *wq,
 750                                          struct work_struct *work)
 751 {
 752         if (enable_work(work)) {
 753                 queue_work(wq, work);
 754                 return true;
 755         }
 756         return false;
 757 }
 758
 759 /*
 760  * Detect attempt to flush system-wide workqueues at compile time when possible.
 761  * Warn attempt to flush system-wide workqueues at runtime.
 762  *
 763  * See https://lkml.kernel.org/r/49925af7-78a8-a3dd-bce6-cfc02e1a9236@I-love.SAKURA.ne.jp
 764  * for reasons and steps for converting system-wide workqueues into local workqueues.
 765  */
 766 extern void __warn_flushing_systemwide_wq(void)
 767         __compiletime_warning("Please avoid flushing system-wide workqueues.");
 768
 769 /* Please stop using this function, for this function will be removed in near future. */
 770 #define flush_scheduled_work()                                          \
 771 ({                                                                      \
 772         __warn_flushing_systemwide_wq();                                \
 773         __flush_workqueue(system_percpu_wq);                                    \
 774 })
 775
 776 #define flush_workqueue(wq)                                             \
 777 ({                                                                      \
 778         struct workqueue_struct *_wq = (wq);                            \
 779                                                                         \
 780         if ((__builtin_constant_p(_wq == system_percpu_wq) &&                   \
 781              _wq == system_percpu_wq) ||                                        \
 782             (__builtin_constant_p(_wq == system_highpri_wq) &&          \
 783              _wq == system_highpri_wq) ||                               \
 784             (__builtin_constant_p(_wq == system_long_wq) &&             \
 785              _wq == system_long_wq) ||                                  \
 786             (__builtin_constant_p(_wq == system_dfl_wq) &&              \
 787              _wq == system_dfl_wq) ||                           \
 788             (__builtin_constant_p(_wq == system_freezable_wq) &&        \
 789              _wq == system_freezable_wq) ||                             \
 790             (__builtin_constant_p(_wq == system_power_efficient_wq) &&  \
 791              _wq == system_power_efficient_wq) ||                       \
 792             (__builtin_constant_p(_wq == system_freezable_power_efficient_wq) && \
 793              _wq == system_freezable_power_efficient_wq))               \
 794                 __warn_flushing_systemwide_wq();                        \
 795         __flush_workqueue(_wq);                                         \
 796 })
 797
 798 /**
 799  * schedule_delayed_work_on - queue work in global workqueue on CPU after delay
 800  * @cpu: cpu to use
 801  * @dwork: job to be done
 802  * @delay: number of jiffies to wait
 803  *
 804  * After waiting for a given time this puts a job in the kernel-global
 805  * workqueue on the specified CPU.
 806  */
 807 static inline bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork,
 808                                             unsigned long delay)
 809 {
 810         return queue_delayed_work_on(cpu, system_percpu_wq, dwork, delay);
 811 }
 812
 813 /**
 814  * schedule_delayed_work - put work task in global workqueue after delay
 815  * @dwork: job to be done
 816  * @delay: number of jiffies to wait or 0 for immediate execution
 817  *
 818  * After waiting for a given time this puts a job in the kernel-global
 819  * workqueue.
 820  */
 821 static inline bool schedule_delayed_work(struct delayed_work *dwork,
 822                                          unsigned long delay)
 823 {
 824         return queue_delayed_work(system_percpu_wq, dwork, delay);
 825 }
 826
 827 #ifndef CONFIG_SMP
 828 static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
 829 {
 830         return fn(arg);
 831 }
 832 static inline long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg)
 833 {
 834         return fn(arg);
 835 }
 836 #else
 837 long work_on_cpu_key(int cpu, long (*fn)(void *),
 838                      void *arg, struct lock_class_key *key);
 839 /*
 840  * A new key is defined for each caller to make sure the work
 841  * associated with the function doesn't share its locking class.
 842  */
 843 #define work_on_cpu(_cpu, _fn, _arg)                    \
 844 ({                                                      \
 845         static struct lock_class_key __key;             \
 846                                                         \
 847         work_on_cpu_key(_cpu, _fn, _arg, &__key);       \
 848 })
 849
 850 #endif /* CONFIG_SMP */
 851
 852 #ifdef CONFIG_FREEZER
 853 extern void freeze_workqueues_begin(void);
 854 extern bool freeze_workqueues_busy(void);
 855 extern void thaw_workqueues(void);
 856 #endif /* CONFIG_FREEZER */
 857
 858 #ifdef CONFIG_SYSFS
 859 int workqueue_sysfs_register(struct workqueue_struct *wq);
 860 #else   /* CONFIG_SYSFS */
 861 static inline int workqueue_sysfs_register(struct workqueue_struct *wq)
 862 { return 0; }
 863 #endif  /* CONFIG_SYSFS */
 864
 865 #ifdef CONFIG_WQ_WATCHDOG
 866 void wq_watchdog_touch(int cpu);
 867 #else   /* CONFIG_WQ_WATCHDOG */
 868 static inline void wq_watchdog_touch(int cpu) { }
 869 #endif  /* CONFIG_WQ_WATCHDOG */
 870
 871 #ifdef CONFIG_SMP
 872 int workqueue_prepare_cpu(unsigned int cpu);
 873 int workqueue_online_cpu(unsigned int cpu);
 874 int workqueue_offline_cpu(unsigned int cpu);
 875 #endif
 876
 877 void __init workqueue_init_early(void);
 878 void __init workqueue_init(void);
 879 void __init workqueue_init_topology(void);
 880
 881 #endif