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_INACTIVE_BIT= 1, /* work item is inactive */ 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_INACTIVE = 1 << WORK_STRUCT_INACTIVE_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 WORK_NR_COLORS = (1 << WORK_STRUCT_COLOR_BITS), 55 56 /* not bound to any CPU, prefer the local CPU */ 57 WORK_CPU_UNBOUND = NR_CPUS, 58 59 /* 60 * Reserve 8 bits off of pwq pointer w/ debugobjects turned off. 61 * This makes pwqs aligned to 256 bytes and allows 16 workqueue 62 * flush colors. 63 */ 64 WORK_STRUCT_FLAG_BITS = WORK_STRUCT_COLOR_SHIFT + 65 WORK_STRUCT_COLOR_BITS, 66 67 /* data contains off-queue information when !WORK_STRUCT_PWQ */ 68 WORK_OFFQ_FLAG_BASE = WORK_STRUCT_COLOR_SHIFT, 69 70 __WORK_OFFQ_CANCELING = WORK_OFFQ_FLAG_BASE, 71 WORK_OFFQ_CANCELING = (1 << __WORK_OFFQ_CANCELING), 72 73 /* 74 * When a work item is off queue, its high bits point to the last 75 * pool it was on. Cap at 31 bits and use the highest number to 76 * indicate that no pool is associated. 77 */ 78 WORK_OFFQ_FLAG_BITS = 1, 79 WORK_OFFQ_POOL_SHIFT = WORK_OFFQ_FLAG_BASE + WORK_OFFQ_FLAG_BITS, 80 WORK_OFFQ_LEFT = BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT, 81 WORK_OFFQ_POOL_BITS = WORK_OFFQ_LEFT <= 31 ? WORK_OFFQ_LEFT : 31, 82 WORK_OFFQ_POOL_NONE = (1LU << WORK_OFFQ_POOL_BITS) - 1, 83 84 /* convenience constants */ 85 WORK_STRUCT_FLAG_MASK = (1UL << WORK_STRUCT_FLAG_BITS) - 1, 86 WORK_STRUCT_WQ_DATA_MASK = ~WORK_STRUCT_FLAG_MASK, 87 WORK_STRUCT_NO_POOL = (unsigned long)WORK_OFFQ_POOL_NONE << WORK_OFFQ_POOL_SHIFT, 88 89 /* bit mask for work_busy() return values */ 90 WORK_BUSY_PENDING = 1 << 0, 91 WORK_BUSY_RUNNING = 1 << 1, 92 93 /* maximum string length for set_worker_desc() */ 94 WORKER_DESC_LEN = 24, 95 }; 96 97 struct work_struct { 98 atomic_long_t data; 99 struct list_head entry; 100 work_func_t func; 101 #ifdef CONFIG_LOCKDEP 102 struct lockdep_map lockdep_map; 103 #endif 104 }; 105 106 #define WORK_DATA_INIT() ATOMIC_LONG_INIT((unsigned long)WORK_STRUCT_NO_POOL) 107 #define WORK_DATA_STATIC_INIT() \ 108 ATOMIC_LONG_INIT((unsigned long)(WORK_STRUCT_NO_POOL | WORK_STRUCT_STATIC)) 109 110 struct delayed_work { 111 struct work_struct work; 112 struct timer_list timer; 113 114 /* target workqueue and CPU ->timer uses to queue ->work */ 115 struct workqueue_struct *wq; 116 int cpu; 117 }; 118 119 struct rcu_work { 120 struct work_struct work; 121 struct rcu_head rcu; 122 123 /* target workqueue ->rcu uses to queue ->work */ 124 struct workqueue_struct *wq; 125 }; 126 127 /** 128 * struct workqueue_attrs - A struct for workqueue attributes. 129 * 130 * This can be used to change attributes of an unbound workqueue. 131 */ 132 struct workqueue_attrs { 133 /** 134 * @nice: nice level 135 */ 136 int nice; 137 138 /** 139 * @cpumask: allowed CPUs 140 */ 141 cpumask_var_t cpumask; 142 143 /** 144 * @no_numa: disable NUMA affinity 145 * 146 * Unlike other fields, ``no_numa`` isn't a property of a worker_pool. It 147 * only modifies how :c:func:`apply_workqueue_attrs` select pools and thus 148 * doesn't participate in pool hash calculations or equality comparisons. 149 */ 150 bool no_numa; 151 }; 152 153 static inline struct delayed_work *to_delayed_work(struct work_struct *work) 154 { 155 return container_of(work, struct delayed_work, work); 156 } 157 158 static inline struct rcu_work *to_rcu_work(struct work_struct *work) 159 { 160 return container_of(work, struct rcu_work, work); 161 } 162 163 struct execute_work { 164 struct work_struct work; 165 }; 166 167 #ifdef CONFIG_LOCKDEP 168 /* 169 * NB: because we have to copy the lockdep_map, setting _key 170 * here is required, otherwise it could get initialised to the 171 * copy of the lockdep_map! 172 */ 173 #define __WORK_INIT_LOCKDEP_MAP(n, k) \ 174 .lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k), 175 #else 176 #define __WORK_INIT_LOCKDEP_MAP(n, k) 177 #endif 178 179 #define __WORK_INITIALIZER(n, f) { \ 180 .data = WORK_DATA_STATIC_INIT(), \ 181 .entry = { &(n).entry, &(n).entry }, \ 182 .func = (f), \ 183 __WORK_INIT_LOCKDEP_MAP(#n, &(n)) \ 184 } 185 186 #define __DELAYED_WORK_INITIALIZER(n, f, tflags) { \ 187 .work = __WORK_INITIALIZER((n).work, (f)), \ 188 .timer = __TIMER_INITIALIZER(delayed_work_timer_fn,\ 189 (tflags) | TIMER_IRQSAFE), \ 190 } 191 192 #define DECLARE_WORK(n, f) \ 193 struct work_struct n = __WORK_INITIALIZER(n, f) 194 195 #define DECLARE_DELAYED_WORK(n, f) \ 196 struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, 0) 197 198 #define DECLARE_DEFERRABLE_WORK(n, f) \ 199 struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f, TIMER_DEFERRABLE) 200 201 #ifdef CONFIG_DEBUG_OBJECTS_WORK 202 extern void __init_work(struct work_struct *work, int onstack); 203 extern void destroy_work_on_stack(struct work_struct *work); 204 extern void destroy_delayed_work_on_stack(struct delayed_work *work); 205 static inline unsigned int work_static(struct work_struct *work) 206 { 207 return *work_data_bits(work) & WORK_STRUCT_STATIC; 208 } 209 #else 210 static inline void __init_work(struct work_struct *work, int onstack) { } 211 static inline void destroy_work_on_stack(struct work_struct *work) { } 212 static inline void destroy_delayed_work_on_stack(struct delayed_work *work) { } 213 static inline unsigned int work_static(struct work_struct *work) { return 0; } 214 #endif 215 216 /* 217 * initialize all of a work item in one go 218 * 219 * NOTE! No point in using "atomic_long_set()": using a direct 220 * assignment of the work data initializer allows the compiler 221 * to generate better code. 222 */ 223 #ifdef CONFIG_LOCKDEP 224 #define __INIT_WORK(_work, _func, _onstack) \ 225 do { \ 226 static struct lock_class_key __key; \ 227 \ 228 __init_work((_work), _onstack); \ 229 (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \ 230 lockdep_init_map(&(_work)->lockdep_map, "(work_completion)"#_work, &__key, 0); \ 231 INIT_LIST_HEAD(&(_work)->entry); \ 232 (_work)->func = (_func); \ 233 } while (0) 234 #else 235 #define __INIT_WORK(_work, _func, _onstack) \ 236 do { \ 237 __init_work((_work), _onstack); \ 238 (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \ 239 INIT_LIST_HEAD(&(_work)->entry); \ 240 (_work)->func = (_func); \ 241 } while (0) 242 #endif 243 244 #define INIT_WORK(_work, _func) \ 245 __INIT_WORK((_work), (_func), 0) 246 247 #define INIT_WORK_ONSTACK(_work, _func) \ 248 __INIT_WORK((_work), (_func), 1) 249 250 #define __INIT_DELAYED_WORK(_work, _func, _tflags) \ 251 do { \ 252 INIT_WORK(&(_work)->work, (_func)); \ 253 __init_timer(&(_work)->timer, \ 254 delayed_work_timer_fn, \ 255 (_tflags) | TIMER_IRQSAFE); \ 256 } while (0) 257 258 #define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags) \ 259 do { \ 260 INIT_WORK_ONSTACK(&(_work)->work, (_func)); \ 261 __init_timer_on_stack(&(_work)->timer, \ 262 delayed_work_timer_fn, \ 263 (_tflags) | TIMER_IRQSAFE); \ 264 } while (0) 265 266 #define INIT_DELAYED_WORK(_work, _func) \ 267 __INIT_DELAYED_WORK(_work, _func, 0) 268 269 #define INIT_DELAYED_WORK_ONSTACK(_work, _func) \ 270 __INIT_DELAYED_WORK_ONSTACK(_work, _func, 0) 271 272 #define INIT_DEFERRABLE_WORK(_work, _func) \ 273 __INIT_DELAYED_WORK(_work, _func, TIMER_DEFERRABLE) 274 275 #define INIT_DEFERRABLE_WORK_ONSTACK(_work, _func) \ 276 __INIT_DELAYED_WORK_ONSTACK(_work, _func, TIMER_DEFERRABLE) 277 278 #define INIT_RCU_WORK(_work, _func) \ 279 INIT_WORK(&(_work)->work, (_func)) 280 281 #define INIT_RCU_WORK_ONSTACK(_work, _func) \ 282 INIT_WORK_ONSTACK(&(_work)->work, (_func)) 283 284 /** 285 * work_pending - Find out whether a work item is currently pending 286 * @work: The work item in question 287 */ 288 #define work_pending(work) \ 289 test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work)) 290 291 /** 292 * delayed_work_pending - Find out whether a delayable work item is currently 293 * pending 294 * @w: The work item in question 295 */ 296 #define delayed_work_pending(w) \ 297 work_pending(&(w)->work) 298 299 /* 300 * Workqueue flags and constants. For details, please refer to 301 * Documentation/core-api/workqueue.rst. 302 */ 303 enum { 304 WQ_UNBOUND = 1 << 1, /* not bound to any cpu */ 305 WQ_FREEZABLE = 1 << 2, /* freeze during suspend */ 306 WQ_MEM_RECLAIM = 1 << 3, /* may be used for memory reclaim */ 307 WQ_HIGHPRI = 1 << 4, /* high priority */ 308 WQ_CPU_INTENSIVE = 1 << 5, /* cpu intensive workqueue */ 309 WQ_SYSFS = 1 << 6, /* visible in sysfs, see workqueue_sysfs_register() */ 310 311 /* 312 * Per-cpu workqueues are generally preferred because they tend to 313 * show better performance thanks to cache locality. Per-cpu 314 * workqueues exclude the scheduler from choosing the CPU to 315 * execute the worker threads, which has an unfortunate side effect 316 * of increasing power consumption. 317 * 318 * The scheduler considers a CPU idle if it doesn't have any task 319 * to execute and tries to keep idle cores idle to conserve power; 320 * however, for example, a per-cpu work item scheduled from an 321 * interrupt handler on an idle CPU will force the scheduler to 322 * execute the work item on that CPU breaking the idleness, which in 323 * turn may lead to more scheduling choices which are sub-optimal 324 * in terms of power consumption. 325 * 326 * Workqueues marked with WQ_POWER_EFFICIENT are per-cpu by default 327 * but become unbound if workqueue.power_efficient kernel param is 328 * specified. Per-cpu workqueues which are identified to 329 * contribute significantly to power-consumption are identified and 330 * marked with this flag and enabling the power_efficient mode 331 * leads to noticeable power saving at the cost of small 332 * performance disadvantage. 333 * 334 * http://thread.gmane.org/gmane.linux.kernel/1480396 335 */ 336 WQ_POWER_EFFICIENT = 1 << 7, 337 338 __WQ_DRAINING = 1 << 16, /* internal: workqueue is draining */ 339 __WQ_ORDERED = 1 << 17, /* internal: workqueue is ordered */ 340 __WQ_LEGACY = 1 << 18, /* internal: create*_workqueue() */ 341 __WQ_ORDERED_EXPLICIT = 1 << 19, /* internal: alloc_ordered_workqueue() */ 342 343 WQ_MAX_ACTIVE = 512, /* I like 512, better ideas? */ 344 WQ_MAX_UNBOUND_PER_CPU = 4, /* 4 * #cpus for unbound wq */ 345 WQ_DFL_ACTIVE = WQ_MAX_ACTIVE / 2, 346 }; 347 348 /* unbound wq's aren't per-cpu, scale max_active according to #cpus */ 349 #define WQ_UNBOUND_MAX_ACTIVE \ 350 max_t(int, WQ_MAX_ACTIVE, num_possible_cpus() * WQ_MAX_UNBOUND_PER_CPU) 351 352 /* 353 * System-wide workqueues which are always present. 354 * 355 * system_wq is the one used by schedule[_delayed]_work[_on](). 356 * Multi-CPU multi-threaded. There are users which expect relatively 357 * short queue flush time. Don't queue works which can run for too 358 * long. 359 * 360 * system_highpri_wq is similar to system_wq but for work items which 361 * require WQ_HIGHPRI. 362 * 363 * system_long_wq is similar to system_wq but may host long running 364 * works. Queue flushing might take relatively long. 365 * 366 * system_unbound_wq is unbound workqueue. Workers are not bound to 367 * any specific CPU, not concurrency managed, and all queued works are 368 * executed immediately as long as max_active limit is not reached and 369 * resources are available. 370 * 371 * system_freezable_wq is equivalent to system_wq except that it's 372 * freezable. 373 * 374 * *_power_efficient_wq are inclined towards saving power and converted 375 * into WQ_UNBOUND variants if 'wq_power_efficient' is enabled; otherwise, 376 * they are same as their non-power-efficient counterparts - e.g. 377 * system_power_efficient_wq is identical to system_wq if 378 * 'wq_power_efficient' is disabled. See WQ_POWER_EFFICIENT for more info. 379 */ 380 extern struct workqueue_struct *system_wq; 381 extern struct workqueue_struct *system_highpri_wq; 382 extern struct workqueue_struct *system_long_wq; 383 extern struct workqueue_struct *system_unbound_wq; 384 extern struct workqueue_struct *system_freezable_wq; 385 extern struct workqueue_struct *system_power_efficient_wq; 386 extern struct workqueue_struct *system_freezable_power_efficient_wq; 387 388 /** 389 * alloc_workqueue - allocate a workqueue 390 * @fmt: printf format for the name of the workqueue 391 * @flags: WQ_* flags 392 * @max_active: max in-flight work items, 0 for default 393 * remaining args: args for @fmt 394 * 395 * Allocate a workqueue with the specified parameters. For detailed 396 * information on WQ_* flags, please refer to 397 * Documentation/core-api/workqueue.rst. 398 * 399 * RETURNS: 400 * Pointer to the allocated workqueue on success, %NULL on failure. 401 */ 402 __printf(1, 4) struct workqueue_struct * 403 alloc_workqueue(const char *fmt, unsigned int flags, int max_active, ...); 404 405 /** 406 * alloc_ordered_workqueue - allocate an ordered workqueue 407 * @fmt: printf format for the name of the workqueue 408 * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful) 409 * @args...: args for @fmt 410 * 411 * Allocate an ordered workqueue. An ordered workqueue executes at 412 * most one work item at any given time in the queued order. They are 413 * implemented as unbound workqueues with @max_active of one. 414 * 415 * RETURNS: 416 * Pointer to the allocated workqueue on success, %NULL on failure. 417 */ 418 #define alloc_ordered_workqueue(fmt, flags, args...) \ 419 alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | \ 420 __WQ_ORDERED_EXPLICIT | (flags), 1, ##args) 421 422 #define create_workqueue(name) \ 423 alloc_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, 1, (name)) 424 #define create_freezable_workqueue(name) \ 425 alloc_workqueue("%s", __WQ_LEGACY | WQ_FREEZABLE | WQ_UNBOUND | \ 426 WQ_MEM_RECLAIM, 1, (name)) 427 #define create_singlethread_workqueue(name) \ 428 alloc_ordered_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, name) 429 430 extern void destroy_workqueue(struct workqueue_struct *wq); 431 432 struct workqueue_attrs *alloc_workqueue_attrs(void); 433 void free_workqueue_attrs(struct workqueue_attrs *attrs); 434 int apply_workqueue_attrs(struct workqueue_struct *wq, 435 const struct workqueue_attrs *attrs); 436 int workqueue_set_unbound_cpumask(cpumask_var_t cpumask); 437 438 extern bool queue_work_on(int cpu, struct workqueue_struct *wq, 439 struct work_struct *work); 440 extern bool queue_work_node(int node, struct workqueue_struct *wq, 441 struct work_struct *work); 442 extern bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq, 443 struct delayed_work *work, unsigned long delay); 444 extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq, 445 struct delayed_work *dwork, unsigned long delay); 446 extern bool queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork); 447 448 extern void flush_workqueue(struct workqueue_struct *wq); 449 extern void drain_workqueue(struct workqueue_struct *wq); 450 451 extern int schedule_on_each_cpu(work_func_t func); 452 453 int execute_in_process_context(work_func_t fn, struct execute_work *); 454 455 extern bool flush_work(struct work_struct *work); 456 extern bool cancel_work_sync(struct work_struct *work); 457 458 extern bool flush_delayed_work(struct delayed_work *dwork); 459 extern bool cancel_delayed_work(struct delayed_work *dwork); 460 extern bool cancel_delayed_work_sync(struct delayed_work *dwork); 461 462 extern bool flush_rcu_work(struct rcu_work *rwork); 463 464 extern void workqueue_set_max_active(struct workqueue_struct *wq, 465 int max_active); 466 extern struct work_struct *current_work(void); 467 extern bool current_is_workqueue_rescuer(void); 468 extern bool workqueue_congested(int cpu, struct workqueue_struct *wq); 469 extern unsigned int work_busy(struct work_struct *work); 470 extern __printf(1, 2) void set_worker_desc(const char *fmt, ...); 471 extern void print_worker_info(const char *log_lvl, struct task_struct *task); 472 extern void show_all_workqueues(void); 473 extern void show_one_workqueue(struct workqueue_struct *wq); 474 extern void wq_worker_comm(char *buf, size_t size, struct task_struct *task); 475 476 /** 477 * queue_work - queue work on a workqueue 478 * @wq: workqueue to use 479 * @work: work to queue 480 * 481 * Returns %false if @work was already on a queue, %true otherwise. 482 * 483 * We queue the work to the CPU on which it was submitted, but if the CPU dies 484 * it can be processed by another CPU. 485 * 486 * Memory-ordering properties: If it returns %true, guarantees that all stores 487 * preceding the call to queue_work() in the program order will be visible from 488 * the CPU which will execute @work by the time such work executes, e.g., 489 * 490 * { x is initially 0 } 491 * 492 * CPU0 CPU1 493 * 494 * WRITE_ONCE(x, 1); [ @work is being executed ] 495 * r0 = queue_work(wq, work); r1 = READ_ONCE(x); 496 * 497 * Forbids: r0 == true && r1 == 0 498 */ 499 static inline bool queue_work(struct workqueue_struct *wq, 500 struct work_struct *work) 501 { 502 return queue_work_on(WORK_CPU_UNBOUND, wq, work); 503 } 504 505 /** 506 * queue_delayed_work - queue work on a workqueue after delay 507 * @wq: workqueue to use 508 * @dwork: delayable work to queue 509 * @delay: number of jiffies to wait before queueing 510 * 511 * Equivalent to queue_delayed_work_on() but tries to use the local CPU. 512 */ 513 static inline bool queue_delayed_work(struct workqueue_struct *wq, 514 struct delayed_work *dwork, 515 unsigned long delay) 516 { 517 return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay); 518 } 519 520 /** 521 * mod_delayed_work - modify delay of or queue a delayed work 522 * @wq: workqueue to use 523 * @dwork: work to queue 524 * @delay: number of jiffies to wait before queueing 525 * 526 * mod_delayed_work_on() on local CPU. 527 */ 528 static inline bool mod_delayed_work(struct workqueue_struct *wq, 529 struct delayed_work *dwork, 530 unsigned long delay) 531 { 532 return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay); 533 } 534 535 /** 536 * schedule_work_on - put work task on a specific cpu 537 * @cpu: cpu to put the work task on 538 * @work: job to be done 539 * 540 * This puts a job on a specific cpu 541 */ 542 static inline bool schedule_work_on(int cpu, struct work_struct *work) 543 { 544 return queue_work_on(cpu, system_wq, work); 545 } 546 547 /** 548 * schedule_work - put work task in global workqueue 549 * @work: job to be done 550 * 551 * Returns %false if @work was already on the kernel-global workqueue and 552 * %true otherwise. 553 * 554 * This puts a job in the kernel-global workqueue if it was not already 555 * queued and leaves it in the same position on the kernel-global 556 * workqueue otherwise. 557 * 558 * Shares the same memory-ordering properties of queue_work(), cf. the 559 * DocBook header of queue_work(). 560 */ 561 static inline bool schedule_work(struct work_struct *work) 562 { 563 return queue_work(system_wq, work); 564 } 565 566 /** 567 * flush_scheduled_work - ensure that any scheduled work has run to completion. 568 * 569 * Forces execution of the kernel-global workqueue and blocks until its 570 * completion. 571 * 572 * Think twice before calling this function! It's very easy to get into 573 * trouble if you don't take great care. Either of the following situations 574 * will lead to deadlock: 575 * 576 * One of the work items currently on the workqueue needs to acquire 577 * a lock held by your code or its caller. 578 * 579 * Your code is running in the context of a work routine. 580 * 581 * They will be detected by lockdep when they occur, but the first might not 582 * occur very often. It depends on what work items are on the workqueue and 583 * what locks they need, which you have no control over. 584 * 585 * In most situations flushing the entire workqueue is overkill; you merely 586 * need to know that a particular work item isn't queued and isn't running. 587 * In such cases you should use cancel_delayed_work_sync() or 588 * cancel_work_sync() instead. 589 */ 590 static inline void flush_scheduled_work(void) 591 { 592 flush_workqueue(system_wq); 593 } 594 595 /** 596 * schedule_delayed_work_on - queue work in global workqueue on CPU after delay 597 * @cpu: cpu to use 598 * @dwork: job to be done 599 * @delay: number of jiffies to wait 600 * 601 * After waiting for a given time this puts a job in the kernel-global 602 * workqueue on the specified CPU. 603 */ 604 static inline bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork, 605 unsigned long delay) 606 { 607 return queue_delayed_work_on(cpu, system_wq, dwork, delay); 608 } 609 610 /** 611 * schedule_delayed_work - put work task in global workqueue after delay 612 * @dwork: job to be done 613 * @delay: number of jiffies to wait or 0 for immediate execution 614 * 615 * After waiting for a given time this puts a job in the kernel-global 616 * workqueue. 617 */ 618 static inline bool schedule_delayed_work(struct delayed_work *dwork, 619 unsigned long delay) 620 { 621 return queue_delayed_work(system_wq, dwork, delay); 622 } 623 624 #ifndef CONFIG_SMP 625 static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg) 626 { 627 return fn(arg); 628 } 629 static inline long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg) 630 { 631 return fn(arg); 632 } 633 #else 634 long work_on_cpu(int cpu, long (*fn)(void *), void *arg); 635 long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg); 636 #endif /* CONFIG_SMP */ 637 638 #ifdef CONFIG_FREEZER 639 extern void freeze_workqueues_begin(void); 640 extern bool freeze_workqueues_busy(void); 641 extern void thaw_workqueues(void); 642 #endif /* CONFIG_FREEZER */ 643 644 #ifdef CONFIG_SYSFS 645 int workqueue_sysfs_register(struct workqueue_struct *wq); 646 #else /* CONFIG_SYSFS */ 647 static inline int workqueue_sysfs_register(struct workqueue_struct *wq) 648 { return 0; } 649 #endif /* CONFIG_SYSFS */ 650 651 #ifdef CONFIG_WQ_WATCHDOG 652 void wq_watchdog_touch(int cpu); 653 #else /* CONFIG_WQ_WATCHDOG */ 654 static inline void wq_watchdog_touch(int cpu) { } 655 #endif /* CONFIG_WQ_WATCHDOG */ 656 657 #ifdef CONFIG_SMP 658 int workqueue_prepare_cpu(unsigned int cpu); 659 int workqueue_online_cpu(unsigned int cpu); 660 int workqueue_offline_cpu(unsigned int cpu); 661 #endif 662 663 void __init workqueue_init_early(void); 664 void __init workqueue_init(void); 665 666 #endif 667