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 #include <linux/workqueue_types.h> 18 19 /* 20 * The first word is the work queue pointer and the flags rolled into 21 * one 22 */ 23 #define work_data_bits(work) ((unsigned long *)(&(work)->data)) 24 25 enum work_bits { 26 WORK_STRUCT_PENDING_BIT = 0, /* work item is pending execution */ 27 WORK_STRUCT_INACTIVE_BIT, /* work item is inactive */ 28 WORK_STRUCT_PWQ_BIT, /* data points to pwq */ 29 WORK_STRUCT_LINKED_BIT, /* next work is linked to this one */ 30 #ifdef CONFIG_DEBUG_OBJECTS_WORK 31 WORK_STRUCT_STATIC_BIT, /* static initializer (debugobjects) */ 32 #endif 33 WORK_STRUCT_FLAG_BITS, 34 35 /* color for workqueue flushing */ 36 WORK_STRUCT_COLOR_SHIFT = WORK_STRUCT_FLAG_BITS, 37 WORK_STRUCT_COLOR_BITS = 4, 38 39 /* 40 * When WORK_STRUCT_PWQ is set, reserve 8 bits off of pwq pointer w/ 41 * debugobjects turned off. This makes pwqs aligned to 256 bytes (512 42 * bytes w/ DEBUG_OBJECTS_WORK) and allows 16 workqueue flush colors. 43 * 44 * MSB 45 * [ pwq pointer ] [ flush color ] [ STRUCT flags ] 46 * 4 bits 4 or 5 bits 47 */ 48 WORK_STRUCT_PWQ_SHIFT = WORK_STRUCT_COLOR_SHIFT + WORK_STRUCT_COLOR_BITS, 49 50 /* 51 * data contains off-queue information when !WORK_STRUCT_PWQ. 52 * 53 * MSB 54 * [ pool ID ] [ disable depth ] [ OFFQ flags ] [ STRUCT flags ] 55 * 16 bits 1 bit 4 or 5 bits 56 */ 57 WORK_OFFQ_FLAG_SHIFT = WORK_STRUCT_FLAG_BITS, 58 WORK_OFFQ_BH_BIT = WORK_OFFQ_FLAG_SHIFT, 59 WORK_OFFQ_FLAG_END, 60 WORK_OFFQ_FLAG_BITS = WORK_OFFQ_FLAG_END - WORK_OFFQ_FLAG_SHIFT, 61 62 WORK_OFFQ_DISABLE_SHIFT = WORK_OFFQ_FLAG_SHIFT + WORK_OFFQ_FLAG_BITS, 63 WORK_OFFQ_DISABLE_BITS = 16, 64 65 /* 66 * When a work item is off queue, the high bits encode off-queue flags 67 * and the last pool it was on. Cap pool ID to 31 bits and use the 68 * highest number to indicate that no pool is associated. 69 */ 70 WORK_OFFQ_POOL_SHIFT = WORK_OFFQ_DISABLE_SHIFT + WORK_OFFQ_DISABLE_BITS, 71 WORK_OFFQ_LEFT = BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT, 72 WORK_OFFQ_POOL_BITS = WORK_OFFQ_LEFT <= 31 ? WORK_OFFQ_LEFT : 31, 73 }; 74 75 enum work_flags { 76 WORK_STRUCT_PENDING = 1 << WORK_STRUCT_PENDING_BIT, 77 WORK_STRUCT_INACTIVE = 1 << WORK_STRUCT_INACTIVE_BIT, 78 WORK_STRUCT_PWQ = 1 << WORK_STRUCT_PWQ_BIT, 79 WORK_STRUCT_LINKED = 1 << WORK_STRUCT_LINKED_BIT, 80 #ifdef CONFIG_DEBUG_OBJECTS_WORK 81 WORK_STRUCT_STATIC = 1 << WORK_STRUCT_STATIC_BIT, 82 #else 83 WORK_STRUCT_STATIC = 0, 84 #endif 85 }; 86 87 enum wq_misc_consts { 88 WORK_NR_COLORS = (1 << WORK_STRUCT_COLOR_BITS), 89 90 /* not bound to any CPU, prefer the local CPU */ 91 WORK_CPU_UNBOUND = NR_CPUS, 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 /* Convenience constants - of type 'unsigned long', not 'enum'! */ 102 #define WORK_OFFQ_BH (1ul << WORK_OFFQ_BH_BIT) 103 #define WORK_OFFQ_FLAG_MASK (((1ul << WORK_OFFQ_FLAG_BITS) - 1) << WORK_OFFQ_FLAG_SHIFT) 104 #define WORK_OFFQ_DISABLE_MASK (((1ul << WORK_OFFQ_DISABLE_BITS) - 1) << WORK_OFFQ_DISABLE_SHIFT) 105 #define WORK_OFFQ_POOL_NONE ((1ul << WORK_OFFQ_POOL_BITS) - 1) 106 #define WORK_STRUCT_NO_POOL (WORK_OFFQ_POOL_NONE << WORK_OFFQ_POOL_SHIFT) 107 #define WORK_STRUCT_PWQ_MASK (~((1ul << WORK_STRUCT_PWQ_SHIFT) - 1)) 108 109 #define WORK_DATA_INIT() ATOMIC_LONG_INIT((unsigned long)WORK_STRUCT_NO_POOL) 110 #define WORK_DATA_STATIC_INIT() \ 111 ATOMIC_LONG_INIT((unsigned long)(WORK_STRUCT_NO_POOL | WORK_STRUCT_STATIC)) 112 113 struct delayed_work { 114 struct work_struct work; 115 struct timer_list timer; 116 117 /* target workqueue and CPU ->timer uses to queue ->work */ 118 struct workqueue_struct *wq; 119 int cpu; 120 }; 121 122 struct rcu_work { 123 struct work_struct work; 124 struct rcu_head rcu; 125 126 /* target workqueue ->rcu uses to queue ->work */ 127 struct workqueue_struct *wq; 128 }; 129 130 enum wq_affn_scope { 131 WQ_AFFN_DFL, /* use system default */ 132 WQ_AFFN_CPU, /* one pod per CPU */ 133 WQ_AFFN_SMT, /* one pod poer SMT */ 134 WQ_AFFN_CACHE, /* one pod per LLC */ 135 WQ_AFFN_NUMA, /* one pod per NUMA node */ 136 WQ_AFFN_SYSTEM, /* one pod across the whole system */ 137 138 WQ_AFFN_NR_TYPES, 139 }; 140 141 /** 142 * struct workqueue_attrs - A struct for workqueue attributes. 143 * 144 * This can be used to change attributes of an unbound workqueue. 145 */ 146 struct workqueue_attrs { 147 /** 148 * @nice: nice level 149 */ 150 int nice; 151 152 /** 153 * @cpumask: allowed CPUs 154 * 155 * Work items in this workqueue are affine to these CPUs and not allowed 156 * to execute on other CPUs. A pool serving a workqueue must have the 157 * same @cpumask. 158 */ 159 cpumask_var_t cpumask; 160 161 /** 162 * @__pod_cpumask: internal attribute used to create per-pod pools 163 * 164 * Internal use only. 165 * 166 * Per-pod unbound worker pools are used to improve locality. Always a 167 * subset of ->cpumask. A workqueue can be associated with multiple 168 * worker pools with disjoint @__pod_cpumask's. Whether the enforcement 169 * of a pool's @__pod_cpumask is strict depends on @affn_strict. 170 */ 171 cpumask_var_t __pod_cpumask; 172 173 /** 174 * @affn_strict: affinity scope is strict 175 * 176 * If clear, workqueue will make a best-effort attempt at starting the 177 * worker inside @__pod_cpumask but the scheduler is free to migrate it 178 * outside. 179 * 180 * If set, workers are only allowed to run inside @__pod_cpumask. 181 */ 182 bool affn_strict; 183 184 /* 185 * Below fields aren't properties of a worker_pool. They only modify how 186 * :c:func:`apply_workqueue_attrs` select pools and thus don't 187 * participate in pool hash calculations or equality comparisons. 188 */ 189 190 /** 191 * @affn_scope: unbound CPU affinity scope 192 * 193 * CPU pods are used to improve execution locality of unbound work 194 * items. There are multiple pod types, one for each wq_affn_scope, and 195 * every CPU in the system belongs to one pod in every pod type. CPUs 196 * that belong to the same pod share the worker pool. For example, 197 * selecting %WQ_AFFN_NUMA makes the workqueue use a separate worker 198 * pool for each NUMA node. 199 */ 200 enum wq_affn_scope affn_scope; 201 202 /** 203 * @ordered: work items must be executed one by one in queueing order 204 */ 205 bool ordered; 206 }; 207 208 static inline struct delayed_work *to_delayed_work(struct work_struct *work) 209 { 210 return container_of(work, struct delayed_work, work); 211 } 212 213 static inline struct rcu_work *to_rcu_work(struct work_struct *work) 214 { 215 return container_of(work, struct rcu_work, work); 216 } 217 218 struct execute_work { 219 struct work_struct work; 220 }; 221 222 #ifdef CONFIG_LOCKDEP 223 /* 224 * NB: because we have to copy the lockdep_map, setting _key 225 * here is required, otherwise it could get initialised to the 226 * copy of the lockdep_map! 227 */ 228 #define __WORK_INIT_LOCKDEP_MAP(n, k) \ 229 .lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k), 230 #else 231 #define __WORK_INIT_LOCKDEP_MAP(n, k) 232 #endif 233 234 #define __WORK_INITIALIZER(n, f) { \ 235 .data = WORK_DATA_STATIC_INIT(), \ 236 .entry = { &(n).entry, &(n).entry }, \ 237 .func = (f), \ 238 __WORK_INIT_LOCKDEP_MAP(#n, &(n)) \ 239 } 240 241 #define __DELAYED_WORK_INITIALIZER(n, f, tflags) { \ 242 .work = __WORK_INITIALIZER((n).work, (f)), \ 243 .timer = __TIMER_INITIALIZER(delayed_work_timer_fn,\ 244 (tflags) | TIMER_IRQSAFE), \ 245 } 246 247 #define DECLARE_WORK(n, f) \ 248 struct work_struct n = __WORK_INITIALIZER(n, f) 249 250 #define DECLARE_DELAYED_WORK(n, f) \ 251 struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, 0) 252 253 #define DECLARE_DEFERRABLE_WORK(n, f) \ 254 struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, TIMER_DEFERRABLE) 255 256 #ifdef CONFIG_DEBUG_OBJECTS_WORK 257 extern void __init_work(struct work_struct *work, int onstack); 258 extern void destroy_work_on_stack(struct work_struct *work); 259 extern void destroy_delayed_work_on_stack(struct delayed_work *work); 260 static inline unsigned int work_static(struct work_struct *work) 261 { 262 return *work_data_bits(work) & WORK_STRUCT_STATIC; 263 } 264 #else 265 static inline void __init_work(struct work_struct *work, int onstack) { } 266 static inline void destroy_work_on_stack(struct work_struct *work) { } 267 static inline void destroy_delayed_work_on_stack(struct delayed_work *work) { } 268 static inline unsigned int work_static(struct work_struct *work) { return 0; } 269 #endif 270 271 /* 272 * initialize all of a work item in one go 273 * 274 * NOTE! No point in using "atomic_long_set()": using a direct 275 * assignment of the work data initializer allows the compiler 276 * to generate better code. 277 */ 278 #ifdef CONFIG_LOCKDEP 279 #define __INIT_WORK_KEY(_work, _func, _onstack, _key) \ 280 do { \ 281 __init_work((_work), _onstack); \ 282 (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \ 283 lockdep_init_map(&(_work)->lockdep_map, "(work_completion)"#_work, (_key), 0); \ 284 INIT_LIST_HEAD(&(_work)->entry); \ 285 (_work)->func = (_func); \ 286 } while (0) 287 #else 288 #define __INIT_WORK_KEY(_work, _func, _onstack, _key) \ 289 do { \ 290 __init_work((_work), _onstack); \ 291 (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \ 292 INIT_LIST_HEAD(&(_work)->entry); \ 293 (_work)->func = (_func); \ 294 } while (0) 295 #endif 296 297 #define __INIT_WORK(_work, _func, _onstack) \ 298 do { \ 299 static __maybe_unused struct lock_class_key __key; \ 300 \ 301 __INIT_WORK_KEY(_work, _func, _onstack, &__key); \ 302 } while (0) 303 304 #define INIT_WORK(_work, _func) \ 305 __INIT_WORK((_work), (_func), 0) 306 307 #define INIT_WORK_ONSTACK(_work, _func) \ 308 __INIT_WORK((_work), (_func), 1) 309 310 #define INIT_WORK_ONSTACK_KEY(_work, _func, _key) \ 311 __INIT_WORK_KEY((_work), (_func), 1, _key) 312 313 #define __INIT_DELAYED_WORK(_work, _func, _tflags) \ 314 do { \ 315 INIT_WORK(&(_work)->work, (_func)); \ 316 __init_timer(&(_work)->timer, \ 317 delayed_work_timer_fn, \ 318 (_tflags) | TIMER_IRQSAFE); \ 319 } while (0) 320 321 #define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags) \ 322 do { \ 323 INIT_WORK_ONSTACK(&(_work)->work, (_func)); \ 324 __init_timer_on_stack(&(_work)->timer, \ 325 delayed_work_timer_fn, \ 326 (_tflags) | TIMER_IRQSAFE); \ 327 } while (0) 328 329 #define INIT_DELAYED_WORK(_work, _func) \ 330 __INIT_DELAYED_WORK(_work, _func, 0) 331 332 #define INIT_DELAYED_WORK_ONSTACK(_work, _func) \ 333 __INIT_DELAYED_WORK_ONSTACK(_work, _func, 0) 334 335 #define INIT_DEFERRABLE_WORK(_work, _func) \ 336 __INIT_DELAYED_WORK(_work, _func, TIMER_DEFERRABLE) 337 338 #define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func) \ 339 __INIT_DELAYED_WORK_ONSTACK(_work, _func, TIMER_DEFERRABLE) 340 341 #define INIT_RCU_WORK(_work, _func) \ 342 INIT_WORK(&(_work)->work, (_func)) 343 344 #define INIT_RCU_WORK_ONSTACK(_work, _func) \ 345 INIT_WORK_ONSTACK(&(_work)->work, (_func)) 346 347 /** 348 * work_pending - Find out whether a work item is currently pending 349 * @work: The work item in question 350 */ 351 #define work_pending(work) \ 352 test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work)) 353 354 /** 355 * delayed_work_pending - Find out whether a delayable work item is currently 356 * pending 357 * @w: The work item in question 358 */ 359 #define delayed_work_pending(w) \ 360 work_pending(&(w)->work) 361 362 /* 363 * Workqueue flags and constants. For details, please refer to 364 * Documentation/core-api/workqueue.rst. 365 */ 366 enum wq_flags { 367 WQ_BH = 1 << 0, /* execute in bottom half (softirq) context */ 368 WQ_UNBOUND = 1 << 1, /* not bound to any cpu */ 369 WQ_FREEZABLE = 1 << 2, /* freeze during suspend */ 370 WQ_MEM_RECLAIM = 1 << 3, /* may be used for memory reclaim */ 371 WQ_HIGHPRI = 1 << 4, /* high priority */ 372 WQ_CPU_INTENSIVE = 1 << 5, /* cpu intensive workqueue */ 373 WQ_SYSFS = 1 << 6, /* visible in sysfs, see workqueue_sysfs_register() */ 374 375 /* 376 * Per-cpu workqueues are generally preferred because they tend to 377 * show better performance thanks to cache locality. Per-cpu 378 * workqueues exclude the scheduler from choosing the CPU to 379 * execute the worker threads, which has an unfortunate side effect 380 * of increasing power consumption. 381 * 382 * The scheduler considers a CPU idle if it doesn't have any task 383 * to execute and tries to keep idle cores idle to conserve power; 384 * however, for example, a per-cpu work item scheduled from an 385 * interrupt handler on an idle CPU will force the scheduler to 386 * execute the work item on that CPU breaking the idleness, which in 387 * turn may lead to more scheduling choices which are sub-optimal 388 * in terms of power consumption. 389 * 390 * Workqueues marked with WQ_POWER_EFFICIENT are per-cpu by default 391 * but become unbound if workqueue.power_efficient kernel param is 392 * specified. Per-cpu workqueues which are identified to 393 * contribute significantly to power-consumption are identified and 394 * marked with this flag and enabling the power_efficient mode 395 * leads to noticeable power saving at the cost of small 396 * performance disadvantage. 397 * 398 * http://thread.gmane.org/gmane.linux.kernel/1480396 399 */ 400 WQ_POWER_EFFICIENT = 1 << 7, 401 402 __WQ_DESTROYING = 1 << 15, /* internal: workqueue is destroying */ 403 __WQ_DRAINING = 1 << 16, /* internal: workqueue is draining */ 404 __WQ_ORDERED = 1 << 17, /* internal: workqueue is ordered */ 405 __WQ_LEGACY = 1 << 18, /* internal: create*_workqueue() */ 406 407 /* BH wq only allows the following flags */ 408 __WQ_BH_ALLOWS = WQ_BH | WQ_HIGHPRI, 409 }; 410 411 enum wq_consts { 412 WQ_MAX_ACTIVE = 512, /* I like 512, better ideas? */ 413 WQ_UNBOUND_MAX_ACTIVE = WQ_MAX_ACTIVE, 414 WQ_DFL_ACTIVE = WQ_MAX_ACTIVE / 2, 415 416 /* 417 * Per-node default cap on min_active. Unless explicitly set, min_active 418 * is set to min(max_active, WQ_DFL_MIN_ACTIVE). For more details, see 419 * workqueue_struct->min_active definition. 420 */ 421 WQ_DFL_MIN_ACTIVE = 8, 422 }; 423 424 /* 425 * System-wide workqueues which are always present. 426 * 427 * system_wq is the one used by schedule[_delayed]_work[_on](). 428 * Multi-CPU multi-threaded. There are users which expect relatively 429 * short queue flush time. Don't queue works which can run for too 430 * long. 431 * 432 * system_highpri_wq is similar to system_wq but for work items which 433 * require WQ_HIGHPRI. 434 * 435 * system_long_wq is similar to system_wq but may host long running 436 * works. Queue flushing might take relatively long. 437 * 438 * system_unbound_wq is unbound workqueue. Workers are not bound to 439 * any specific CPU, not concurrency managed, and all queued works are 440 * executed immediately as long as max_active limit is not reached and 441 * resources are available. 442 * 443 * system_freezable_wq is equivalent to system_wq except that it's 444 * freezable. 445 * 446 * *_power_efficient_wq are inclined towards saving power and converted 447 * into WQ_UNBOUND variants if 'wq_power_efficient' is enabled; otherwise, 448 * they are same as their non-power-efficient counterparts - e.g. 449 * system_power_efficient_wq is identical to system_wq if 450 * 'wq_power_efficient' is disabled. See WQ_POWER_EFFICIENT for more info. 451 * 452 * system_bh[_highpri]_wq are convenience interface to softirq. BH work items 453 * are executed in the queueing CPU's BH context in the queueing order. 454 */ 455 extern struct workqueue_struct *system_wq; 456 extern struct workqueue_struct *system_highpri_wq; 457 extern struct workqueue_struct *system_long_wq; 458 extern struct workqueue_struct *system_unbound_wq; 459 extern struct workqueue_struct *system_freezable_wq; 460 extern struct workqueue_struct *system_power_efficient_wq; 461 extern struct workqueue_struct *system_freezable_power_efficient_wq; 462 extern struct workqueue_struct *system_bh_wq; 463 extern struct workqueue_struct *system_bh_highpri_wq; 464 465 void workqueue_softirq_action(bool highpri); 466 void workqueue_softirq_dead(unsigned int cpu); 467 468 /** 469 * alloc_workqueue - allocate a workqueue 470 * @fmt: printf format for the name of the workqueue 471 * @flags: WQ_* flags 472 * @max_active: max in-flight work items, 0 for default 473 * remaining args: args for @fmt 474 * 475 * For a per-cpu workqueue, @max_active limits the number of in-flight work 476 * items for each CPU. e.g. @max_active of 1 indicates that each CPU can be 477 * executing at most one work item for the workqueue. 478 * 479 * For unbound workqueues, @max_active limits the number of in-flight work items 480 * for the whole system. e.g. @max_active of 16 indicates that that there can be 481 * at most 16 work items executing for the workqueue in the whole system. 482 * 483 * As sharing the same active counter for an unbound workqueue across multiple 484 * NUMA nodes can be expensive, @max_active is distributed to each NUMA node 485 * according to the proportion of the number of online CPUs and enforced 486 * independently. 487 * 488 * Depending on online CPU distribution, a node may end up with per-node 489 * max_active which is significantly lower than @max_active, which can lead to 490 * deadlocks if the per-node concurrency limit is lower than the maximum number 491 * of interdependent work items for the workqueue. 492 * 493 * To guarantee forward progress regardless of online CPU distribution, the 494 * concurrency limit on every node is guaranteed to be equal to or greater than 495 * min_active which is set to min(@max_active, %WQ_DFL_MIN_ACTIVE). This means 496 * that the sum of per-node max_active's may be larger than @max_active. 497 * 498 * For detailed information on %WQ_* flags, please refer to 499 * Documentation/core-api/workqueue.rst. 500 * 501 * RETURNS: 502 * Pointer to the allocated workqueue on success, %NULL on failure. 503 */ 504 __printf(1, 4) struct workqueue_struct * 505 alloc_workqueue(const char *fmt, unsigned int flags, int max_active, ...); 506 507 /** 508 * alloc_ordered_workqueue - allocate an ordered workqueue 509 * @fmt: printf format for the name of the workqueue 510 * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful) 511 * @args: args for @fmt 512 * 513 * Allocate an ordered workqueue. An ordered workqueue executes at 514 * most one work item at any given time in the queued order. They are 515 * implemented as unbound workqueues with @max_active of one. 516 * 517 * RETURNS: 518 * Pointer to the allocated workqueue on success, %NULL on failure. 519 */ 520 #define alloc_ordered_workqueue(fmt, flags, args...) \ 521 alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | (flags), 1, ##args) 522 523 #define create_workqueue(name) \ 524 alloc_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, 1, (name)) 525 #define create_freezable_workqueue(name) \ 526 alloc_workqueue("%s", __WQ_LEGACY | WQ_FREEZABLE | WQ_UNBOUND | \ 527 WQ_MEM_RECLAIM, 1, (name)) 528 #define create_singlethread_workqueue(name) \ 529 alloc_ordered_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, name) 530 531 #define from_work(var, callback_work, work_fieldname) \ 532 container_of(callback_work, typeof(*var), work_fieldname) 533 534 extern void destroy_workqueue(struct workqueue_struct *wq); 535 536 struct workqueue_attrs *alloc_workqueue_attrs(void); 537 void free_workqueue_attrs(struct workqueue_attrs *attrs); 538 int apply_workqueue_attrs(struct workqueue_struct *wq, 539 const struct workqueue_attrs *attrs); 540 extern int workqueue_unbound_exclude_cpumask(cpumask_var_t cpumask); 541 542 extern bool queue_work_on(int cpu, struct workqueue_struct *wq, 543 struct work_struct *work); 544 extern bool queue_work_node(int node, struct workqueue_struct *wq, 545 struct work_struct *work); 546 extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq, 547 struct delayed_work *work, unsigned long delay); 548 extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq, 549 struct delayed_work *dwork, unsigned long delay); 550 extern bool queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork); 551 552 extern void __flush_workqueue(struct workqueue_struct *wq); 553 extern void drain_workqueue(struct workqueue_struct *wq); 554 555 extern int schedule_on_each_cpu(work_func_t func); 556 557 int execute_in_process_context(work_func_t fn, struct execute_work *); 558 559 extern bool flush_work(struct work_struct *work); 560 extern bool cancel_work(struct work_struct *work); 561 extern bool cancel_work_sync(struct work_struct *work); 562 563 extern bool flush_delayed_work(struct delayed_work *dwork); 564 extern bool cancel_delayed_work(struct delayed_work *dwork); 565 extern bool cancel_delayed_work_sync(struct delayed_work *dwork); 566 567 extern bool disable_work(struct work_struct *work); 568 extern bool disable_work_sync(struct work_struct *work); 569 extern bool enable_work(struct work_struct *work); 570 571 extern bool disable_delayed_work(struct delayed_work *dwork); 572 extern bool disable_delayed_work_sync(struct delayed_work *dwork); 573 extern bool enable_delayed_work(struct delayed_work *dwork); 574 575 extern bool flush_rcu_work(struct rcu_work *rwork); 576 577 extern void workqueue_set_max_active(struct workqueue_struct *wq, 578 int max_active); 579 extern void workqueue_set_min_active(struct workqueue_struct *wq, 580 int min_active); 581 extern struct work_struct *current_work(void); 582 extern bool current_is_workqueue_rescuer(void); 583 extern bool workqueue_congested(int cpu, struct workqueue_struct *wq); 584 extern unsigned int work_busy(struct work_struct *work); 585 extern __printf(1, 2) void set_worker_desc(const char *fmt, ...); 586 extern void print_worker_info(const char *log_lvl, struct task_struct *task); 587 extern void show_all_workqueues(void); 588 extern void show_freezable_workqueues(void); 589 extern void show_one_workqueue(struct workqueue_struct *wq); 590 extern void wq_worker_comm(char *buf, size_t size, struct task_struct *task); 591 592 /** 593 * queue_work - queue work on a workqueue 594 * @wq: workqueue to use 595 * @work: work to queue 596 * 597 * Returns %false if @work was already on a queue, %true otherwise. 598 * 599 * We queue the work to the CPU on which it was submitted, but if the CPU dies 600 * it can be processed by another CPU. 601 * 602 * Memory-ordering properties: If it returns %true, guarantees that all stores 603 * preceding the call to queue_work() in the program order will be visible from 604 * the CPU which will execute @work by the time such work executes, e.g., 605 * 606 * { x is initially 0 } 607 * 608 * CPU0 CPU1 609 * 610 * WRITE_ONCE(x, 1); [ @work is being executed ] 611 * r0 = queue_work(wq, work); r1 = READ_ONCE(x); 612 * 613 * Forbids: r0 == true && r1 == 0 614 */ 615 static inline bool queue_work(struct workqueue_struct *wq, 616 struct work_struct *work) 617 { 618 return queue_work_on(WORK_CPU_UNBOUND, wq, work); 619 } 620 621 /** 622 * queue_delayed_work - queue work on a workqueue after delay 623 * @wq: workqueue to use 624 * @dwork: delayable work to queue 625 * @delay: number of jiffies to wait before queueing 626 * 627 * Equivalent to queue_delayed_work_on() but tries to use the local CPU. 628 */ 629 static inline bool queue_delayed_work(struct workqueue_struct *wq, 630 struct delayed_work *dwork, 631 unsigned long delay) 632 { 633 return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay); 634 } 635 636 /** 637 * mod_delayed_work - modify delay of or queue a delayed work 638 * @wq: workqueue to use 639 * @dwork: work to queue 640 * @delay: number of jiffies to wait before queueing 641 * 642 * mod_delayed_work_on() on local CPU. 643 */ 644 static inline bool mod_delayed_work(struct workqueue_struct *wq, 645 struct delayed_work *dwork, 646 unsigned long delay) 647 { 648 return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay); 649 } 650 651 /** 652 * schedule_work_on - put work task on a specific cpu 653 * @cpu: cpu to put the work task on 654 * @work: job to be done 655 * 656 * This puts a job on a specific cpu 657 */ 658 static inline bool schedule_work_on(int cpu, struct work_struct *work) 659 { 660 return queue_work_on(cpu, system_wq, work); 661 } 662 663 /** 664 * schedule_work - put work task in global workqueue 665 * @work: job to be done 666 * 667 * Returns %false if @work was already on the kernel-global workqueue and 668 * %true otherwise. 669 * 670 * This puts a job in the kernel-global workqueue if it was not already 671 * queued and leaves it in the same position on the kernel-global 672 * workqueue otherwise. 673 * 674 * Shares the same memory-ordering properties of queue_work(), cf. the 675 * DocBook header of queue_work(). 676 */ 677 static inline bool schedule_work(struct work_struct *work) 678 { 679 return queue_work(system_wq, work); 680 } 681 682 /* 683 * Detect attempt to flush system-wide workqueues at compile time when possible. 684 * Warn attempt to flush system-wide workqueues at runtime. 685 * 686 * See https://lkml.kernel.org/r/[email protected] 687 * for reasons and steps for converting system-wide workqueues into local workqueues. 688 */ 689 extern void __warn_flushing_systemwide_wq(void) 690 __compiletime_warning("Please avoid flushing system-wide workqueues."); 691 692 /* Please stop using this function, for this function will be removed in near future. */ 693 #define flush_scheduled_work() \ 694 ({ \ 695 __warn_flushing_systemwide_wq(); \ 696 __flush_workqueue(system_wq); \ 697 }) 698 699 #define flush_workqueue(wq) \ 700 ({ \ 701 struct workqueue_struct *_wq = (wq); \ 702 \ 703 if ((__builtin_constant_p(_wq == system_wq) && \ 704 _wq == system_wq) || \ 705 (__builtin_constant_p(_wq == system_highpri_wq) && \ 706 _wq == system_highpri_wq) || \ 707 (__builtin_constant_p(_wq == system_long_wq) && \ 708 _wq == system_long_wq) || \ 709 (__builtin_constant_p(_wq == system_unbound_wq) && \ 710 _wq == system_unbound_wq) || \ 711 (__builtin_constant_p(_wq == system_freezable_wq) && \ 712 _wq == system_freezable_wq) || \ 713 (__builtin_constant_p(_wq == system_power_efficient_wq) && \ 714 _wq == system_power_efficient_wq) || \ 715 (__builtin_constant_p(_wq == system_freezable_power_efficient_wq) && \ 716 _wq == system_freezable_power_efficient_wq)) \ 717 __warn_flushing_systemwide_wq(); \ 718 __flush_workqueue(_wq); \ 719 }) 720 721 /** 722 * schedule_delayed_work_on - queue work in global workqueue on CPU after delay 723 * @cpu: cpu to use 724 * @dwork: job to be done 725 * @delay: number of jiffies to wait 726 * 727 * After waiting for a given time this puts a job in the kernel-global 728 * workqueue on the specified CPU. 729 */ 730 static inline bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork, 731 unsigned long delay) 732 { 733 return queue_delayed_work_on(cpu, system_wq, dwork, delay); 734 } 735 736 /** 737 * schedule_delayed_work - put work task in global workqueue after delay 738 * @dwork: job to be done 739 * @delay: number of jiffies to wait or 0 for immediate execution 740 * 741 * After waiting for a given time this puts a job in the kernel-global 742 * workqueue. 743 */ 744 static inline bool schedule_delayed_work(struct delayed_work *dwork, 745 unsigned long delay) 746 { 747 return queue_delayed_work(system_wq, dwork, delay); 748 } 749 750 #ifndef CONFIG_SMP 751 static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg) 752 { 753 return fn(arg); 754 } 755 static inline long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg) 756 { 757 return fn(arg); 758 } 759 #else 760 long work_on_cpu_key(int cpu, long (*fn)(void *), 761 void *arg, struct lock_class_key *key); 762 /* 763 * A new key is defined for each caller to make sure the work 764 * associated with the function doesn't share its locking class. 765 */ 766 #define work_on_cpu(_cpu, _fn, _arg) \ 767 ({ \ 768 static struct lock_class_key __key; \ 769 \ 770 work_on_cpu_key(_cpu, _fn, _arg, &__key); \ 771 }) 772 773 long work_on_cpu_safe_key(int cpu, long (*fn)(void *), 774 void *arg, struct lock_class_key *key); 775 776 /* 777 * A new key is defined for each caller to make sure the work 778 * associated with the function doesn't share its locking class. 779 */ 780 #define work_on_cpu_safe(_cpu, _fn, _arg) \ 781 ({ \ 782 static struct lock_class_key __key; \ 783 \ 784 work_on_cpu_safe_key(_cpu, _fn, _arg, &__key); \ 785 }) 786 #endif /* CONFIG_SMP */ 787 788 #ifdef CONFIG_FREEZER 789 extern void freeze_workqueues_begin(void); 790 extern bool freeze_workqueues_busy(void); 791 extern void thaw_workqueues(void); 792 #endif /* CONFIG_FREEZER */ 793 794 #ifdef CONFIG_SYSFS 795 int workqueue_sysfs_register(struct workqueue_struct *wq); 796 #else /* CONFIG_SYSFS */ 797 static inline int workqueue_sysfs_register(struct workqueue_struct *wq) 798 { return 0; } 799 #endif /* CONFIG_SYSFS */ 800 801 #ifdef CONFIG_WQ_WATCHDOG 802 void wq_watchdog_touch(int cpu); 803 #else /* CONFIG_WQ_WATCHDOG */ 804 static inline void wq_watchdog_touch(int cpu) { } 805 #endif /* CONFIG_WQ_WATCHDOG */ 806 807 #ifdef CONFIG_SMP 808 int workqueue_prepare_cpu(unsigned int cpu); 809 int workqueue_online_cpu(unsigned int cpu); 810 int workqueue_offline_cpu(unsigned int cpu); 811 #endif 812 813 void __init workqueue_init_early(void); 814 void __init workqueue_init(void); 815 void __init workqueue_init_topology(void); 816 817 #endif 818