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(struct work_struct *work); |
457 | extern bool cancel_work_sync(struct work_struct *work); |
458 | |
459 | extern bool flush_delayed_work(struct delayed_work *dwork); |
460 | extern bool cancel_delayed_work(struct delayed_work *dwork); |
461 | extern bool cancel_delayed_work_sync(struct delayed_work *dwork); |
462 | |
463 | extern bool flush_rcu_work(struct rcu_work *rwork); |
464 | |
465 | extern void workqueue_set_max_active(struct workqueue_struct *wq, |
466 | int max_active); |
467 | extern struct work_struct *current_work(void); |
468 | extern bool current_is_workqueue_rescuer(void); |
469 | extern bool workqueue_congested(int cpu, struct workqueue_struct *wq); |
470 | extern unsigned int work_busy(struct work_struct *work); |
471 | extern __printf(1, 2) void set_worker_desc(const char *fmt, ...); |
472 | extern void print_worker_info(const char *log_lvl, struct task_struct *task); |
473 | extern void show_all_workqueues(void); |
474 | extern void show_one_workqueue(struct workqueue_struct *wq); |
475 | extern void wq_worker_comm(char *buf, size_t size, struct task_struct *task); |
476 | |
477 | /** |
478 | * queue_work - queue work on a workqueue |
479 | * @wq: workqueue to use |
480 | * @work: work to queue |
481 | * |
482 | * Returns %false if @work was already on a queue, %true otherwise. |
483 | * |
484 | * We queue the work to the CPU on which it was submitted, but if the CPU dies |
485 | * it can be processed by another CPU. |
486 | * |
487 | * Memory-ordering properties: If it returns %true, guarantees that all stores |
488 | * preceding the call to queue_work() in the program order will be visible from |
489 | * the CPU which will execute @work by the time such work executes, e.g., |
490 | * |
491 | * { x is initially 0 } |
492 | * |
493 | * CPU0 CPU1 |
494 | * |
495 | * WRITE_ONCE(x, 1); [ @work is being executed ] |
496 | * r0 = queue_work(wq, work); r1 = READ_ONCE(x); |
497 | * |
498 | * Forbids: r0 == true && r1 == 0 |
499 | */ |
500 | static inline bool queue_work(struct workqueue_struct *wq, |
501 | struct work_struct *work) |
502 | { |
503 | return queue_work_on(WORK_CPU_UNBOUND, wq, work); |
504 | } |
505 | |
506 | /** |
507 | * queue_delayed_work - queue work on a workqueue after delay |
508 | * @wq: workqueue to use |
509 | * @dwork: delayable work to queue |
510 | * @delay: number of jiffies to wait before queueing |
511 | * |
512 | * Equivalent to queue_delayed_work_on() but tries to use the local CPU. |
513 | */ |
514 | static inline bool queue_delayed_work(struct workqueue_struct *wq, |
515 | struct delayed_work *dwork, |
516 | unsigned long delay) |
517 | { |
518 | return queue_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay); |
519 | } |
520 | |
521 | /** |
522 | * mod_delayed_work - modify delay of or queue a delayed work |
523 | * @wq: workqueue to use |
524 | * @dwork: work to queue |
525 | * @delay: number of jiffies to wait before queueing |
526 | * |
527 | * mod_delayed_work_on() on local CPU. |
528 | */ |
529 | static inline bool mod_delayed_work(struct workqueue_struct *wq, |
530 | struct delayed_work *dwork, |
531 | unsigned long delay) |
532 | { |
533 | return mod_delayed_work_on(WORK_CPU_UNBOUND, wq, dwork, delay); |
534 | } |
535 | |
536 | /** |
537 | * schedule_work_on - put work task on a specific cpu |
538 | * @cpu: cpu to put the work task on |
539 | * @work: job to be done |
540 | * |
541 | * This puts a job on a specific cpu |
542 | */ |
543 | static inline bool schedule_work_on(int cpu, struct work_struct *work) |
544 | { |
545 | return queue_work_on(cpu, system_wq, work); |
546 | } |
547 | |
548 | /** |
549 | * schedule_work - put work task in global workqueue |
550 | * @work: job to be done |
551 | * |
552 | * Returns %false if @work was already on the kernel-global workqueue and |
553 | * %true otherwise. |
554 | * |
555 | * This puts a job in the kernel-global workqueue if it was not already |
556 | * queued and leaves it in the same position on the kernel-global |
557 | * workqueue otherwise. |
558 | * |
559 | * Shares the same memory-ordering properties of queue_work(), cf. the |
560 | * DocBook header of queue_work(). |
561 | */ |
562 | static inline bool schedule_work(struct work_struct *work) |
563 | { |
564 | return queue_work(system_wq, work); |
565 | } |
566 | |
567 | /* |
568 | * Detect attempt to flush system-wide workqueues at compile time when possible. |
569 | * |
570 | * See https://lkml.kernel.org/r/49925af7-78a8-a3dd-bce6-cfc02e1a9236@I-love.SAKURA.ne.jp |
571 | * for reasons and steps for converting system-wide workqueues into local workqueues. |
572 | */ |
573 | extern void __warn_flushing_systemwide_wq(void) |
574 | __compiletime_warning("Please avoid flushing system-wide workqueues." ); |
575 | |
576 | /** |
577 | * flush_scheduled_work - ensure that any scheduled work has run to completion. |
578 | * |
579 | * Forces execution of the kernel-global workqueue and blocks until its |
580 | * completion. |
581 | * |
582 | * It's very easy to get into trouble if you don't take great care. |
583 | * Either of the following situations will lead to deadlock: |
584 | * |
585 | * One of the work items currently on the workqueue needs to acquire |
586 | * a lock held by your code or its caller. |
587 | * |
588 | * Your code is running in the context of a work routine. |
589 | * |
590 | * They will be detected by lockdep when they occur, but the first might not |
591 | * occur very often. It depends on what work items are on the workqueue and |
592 | * what locks they need, which you have no control over. |
593 | * |
594 | * In most situations flushing the entire workqueue is overkill; you merely |
595 | * need to know that a particular work item isn't queued and isn't running. |
596 | * In such cases you should use cancel_delayed_work_sync() or |
597 | * cancel_work_sync() instead. |
598 | * |
599 | * Please stop calling this function! A conversion to stop flushing system-wide |
600 | * workqueues is in progress. This function will be removed after all in-tree |
601 | * users stopped calling this function. |
602 | */ |
603 | /* |
604 | * The background of commit 771c035372a036f8 ("deprecate the |
605 | * '__deprecated' attribute warnings entirely and for good") is that, |
606 | * since Linus builds all modules between every single pull he does, |
607 | * the standard kernel build needs to be _clean_ in order to be able to |
608 | * notice when new problems happen. Therefore, don't emit warning while |
609 | * there are in-tree users. |
610 | */ |
611 | #define flush_scheduled_work() \ |
612 | ({ \ |
613 | if (0) \ |
614 | __warn_flushing_systemwide_wq(); \ |
615 | __flush_workqueue(system_wq); \ |
616 | }) |
617 | |
618 | /* |
619 | * Although there is no longer in-tree caller, for now just emit warning |
620 | * in order to give out-of-tree callers time to update. |
621 | */ |
622 | #define flush_workqueue(wq) \ |
623 | ({ \ |
624 | struct workqueue_struct *_wq = (wq); \ |
625 | \ |
626 | if ((__builtin_constant_p(_wq == system_wq) && \ |
627 | _wq == system_wq) || \ |
628 | (__builtin_constant_p(_wq == system_highpri_wq) && \ |
629 | _wq == system_highpri_wq) || \ |
630 | (__builtin_constant_p(_wq == system_long_wq) && \ |
631 | _wq == system_long_wq) || \ |
632 | (__builtin_constant_p(_wq == system_unbound_wq) && \ |
633 | _wq == system_unbound_wq) || \ |
634 | (__builtin_constant_p(_wq == system_freezable_wq) && \ |
635 | _wq == system_freezable_wq) || \ |
636 | (__builtin_constant_p(_wq == system_power_efficient_wq) && \ |
637 | _wq == system_power_efficient_wq) || \ |
638 | (__builtin_constant_p(_wq == system_freezable_power_efficient_wq) && \ |
639 | _wq == system_freezable_power_efficient_wq)) \ |
640 | __warn_flushing_systemwide_wq(); \ |
641 | __flush_workqueue(_wq); \ |
642 | }) |
643 | |
644 | /** |
645 | * schedule_delayed_work_on - queue work in global workqueue on CPU after delay |
646 | * @cpu: cpu to use |
647 | * @dwork: job to be done |
648 | * @delay: number of jiffies to wait |
649 | * |
650 | * After waiting for a given time this puts a job in the kernel-global |
651 | * workqueue on the specified CPU. |
652 | */ |
653 | static inline bool schedule_delayed_work_on(int cpu, struct delayed_work *dwork, |
654 | unsigned long delay) |
655 | { |
656 | return queue_delayed_work_on(cpu, system_wq, dwork, delay); |
657 | } |
658 | |
659 | /** |
660 | * schedule_delayed_work - put work task in global workqueue after delay |
661 | * @dwork: job to be done |
662 | * @delay: number of jiffies to wait or 0 for immediate execution |
663 | * |
664 | * After waiting for a given time this puts a job in the kernel-global |
665 | * workqueue. |
666 | */ |
667 | static inline bool schedule_delayed_work(struct delayed_work *dwork, |
668 | unsigned long delay) |
669 | { |
670 | return queue_delayed_work(system_wq, dwork, delay); |
671 | } |
672 | |
673 | #ifndef CONFIG_SMP |
674 | static inline long work_on_cpu(int cpu, long (*fn)(void *), void *arg) |
675 | { |
676 | return fn(arg); |
677 | } |
678 | static inline long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg) |
679 | { |
680 | return fn(arg); |
681 | } |
682 | #else |
683 | long work_on_cpu(int cpu, long (*fn)(void *), void *arg); |
684 | long work_on_cpu_safe(int cpu, long (*fn)(void *), void *arg); |
685 | #endif /* CONFIG_SMP */ |
686 | |
687 | #ifdef CONFIG_FREEZER |
688 | extern void freeze_workqueues_begin(void); |
689 | extern bool freeze_workqueues_busy(void); |
690 | extern void thaw_workqueues(void); |
691 | #endif /* CONFIG_FREEZER */ |
692 | |
693 | #ifdef CONFIG_SYSFS |
694 | int workqueue_sysfs_register(struct workqueue_struct *wq); |
695 | #else /* CONFIG_SYSFS */ |
696 | static inline int workqueue_sysfs_register(struct workqueue_struct *wq) |
697 | { return 0; } |
698 | #endif /* CONFIG_SYSFS */ |
699 | |
700 | #ifdef CONFIG_WQ_WATCHDOG |
701 | void wq_watchdog_touch(int cpu); |
702 | #else /* CONFIG_WQ_WATCHDOG */ |
703 | static inline void wq_watchdog_touch(int cpu) { } |
704 | #endif /* CONFIG_WQ_WATCHDOG */ |
705 | |
706 | #ifdef CONFIG_SMP |
707 | int workqueue_prepare_cpu(unsigned int cpu); |
708 | int workqueue_online_cpu(unsigned int cpu); |
709 | int workqueue_offline_cpu(unsigned int cpu); |
710 | #endif |
711 | |
712 | void __init workqueue_init_early(void); |
713 | void __init workqueue_init(void); |
714 | |
715 | #endif |
716 | |