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1 /*
2 * workqueue.h --- work queue handling for Linux.
3 */
4
5 #ifndef _LINUX_WORKQUEUE_H
6 #define _LINUX_WORKQUEUE_H
7
8 #include <linux/timer.h>
9 #include <linux/linkage.h>
10 #include <linux/bitops.h>
11 #include <linux/lockdep.h>
12 #include <linux/threads.h>
13 #include <linux/atomic.h>
14
15 struct workqueue_struct;
16
17 struct work_struct;
18 typedef void (*work_func_t)(struct work_struct *work);
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 {
27 WORK_STRUCT_PENDING_BIT = 0, /* work item is pending execution */
28 WORK_STRUCT_DELAYED_BIT = 1, /* work item is delayed */
29 WORK_STRUCT_CWQ_BIT = 2, /* data points to cwq */
30 WORK_STRUCT_LINKED_BIT = 3, /* next work is linked to this one */
31 #ifdef CONFIG_DEBUG_OBJECTS_WORK
32 WORK_STRUCT_STATIC_BIT = 4, /* static initializer (debugobjects) */
33 WORK_STRUCT_COLOR_SHIFT = 5, /* color for workqueue flushing */
34 #else
35 WORK_STRUCT_COLOR_SHIFT = 4, /* color for workqueue flushing */
36 #endif
37
38 WORK_STRUCT_COLOR_BITS = 4,
39
40 WORK_STRUCT_PENDING = 1 << WORK_STRUCT_PENDING_BIT,
41 WORK_STRUCT_DELAYED = 1 << WORK_STRUCT_DELAYED_BIT,
42 WORK_STRUCT_CWQ = 1 << WORK_STRUCT_CWQ_BIT,
43 WORK_STRUCT_LINKED = 1 << WORK_STRUCT_LINKED_BIT,
44 #ifdef CONFIG_DEBUG_OBJECTS_WORK
45 WORK_STRUCT_STATIC = 1 << WORK_STRUCT_STATIC_BIT,
46 #else
47 WORK_STRUCT_STATIC = 0,
48 #endif
49
50 /*
51 * The last color is no color used for works which don't
52 * participate in workqueue flushing.
53 */
54 WORK_NR_COLORS = (1 << WORK_STRUCT_COLOR_BITS) - 1,
55 WORK_NO_COLOR = WORK_NR_COLORS,
56
57 /* special cpu IDs */
58 WORK_CPU_UNBOUND = NR_CPUS,
59 WORK_CPU_NONE = NR_CPUS + 1,
60 WORK_CPU_LAST = WORK_CPU_NONE,
61
62 /*
63 * Reserve 7 bits off of cwq pointer w/ debugobjects turned
64 * off. This makes cwqs aligned to 256 bytes and allows 15
65 * workqueue flush colors.
66 */
67 WORK_STRUCT_FLAG_BITS = WORK_STRUCT_COLOR_SHIFT +
68 WORK_STRUCT_COLOR_BITS,
69
70 WORK_STRUCT_FLAG_MASK = (1UL << WORK_STRUCT_FLAG_BITS) - 1,
71 WORK_STRUCT_WQ_DATA_MASK = ~WORK_STRUCT_FLAG_MASK,
72 WORK_STRUCT_NO_CPU = WORK_CPU_NONE << WORK_STRUCT_FLAG_BITS,
73
74 /* bit mask for work_busy() return values */
75 WORK_BUSY_PENDING = 1 << 0,
76 WORK_BUSY_RUNNING = 1 << 1,
77 };
78
79 struct work_struct {
80 atomic_long_t data;
81 struct list_head entry;
82 work_func_t func;
83 #ifdef CONFIG_LOCKDEP
84 struct lockdep_map lockdep_map;
85 #endif
86 };
87
88 #define WORK_DATA_INIT() ATOMIC_LONG_INIT(WORK_STRUCT_NO_CPU)
89 #define WORK_DATA_STATIC_INIT() \
90 ATOMIC_LONG_INIT(WORK_STRUCT_NO_CPU | WORK_STRUCT_STATIC)
91
92 struct delayed_work {
93 struct work_struct work;
94 struct timer_list timer;
95 };
96
97 static inline struct delayed_work *to_delayed_work(struct work_struct *work)
98 {
99 return container_of(work, struct delayed_work, work);
100 }
101
102 struct execute_work {
103 struct work_struct work;
104 };
105
106 #ifdef CONFIG_LOCKDEP
107 /*
108 * NB: because we have to copy the lockdep_map, setting _key
109 * here is required, otherwise it could get initialised to the
110 * copy of the lockdep_map!
111 */
112 #define __WORK_INIT_LOCKDEP_MAP(n, k) \
113 .lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k),
114 #else
115 #define __WORK_INIT_LOCKDEP_MAP(n, k)
116 #endif
117
118 #define __WORK_INITIALIZER(n, f) { \
119 .data = WORK_DATA_STATIC_INIT(), \
120 .entry = { &(n).entry, &(n).entry }, \
121 .func = (f), \
122 __WORK_INIT_LOCKDEP_MAP(#n, &(n)) \
123 }
124
125 #define __DELAYED_WORK_INITIALIZER(n, f) { \
126 .work = __WORK_INITIALIZER((n).work, (f)), \
127 .timer = TIMER_INITIALIZER(NULL, 0, 0), \
128 }
129
130 #define __DEFERRED_WORK_INITIALIZER(n, f) { \
131 .work = __WORK_INITIALIZER((n).work, (f)), \
132 .timer = TIMER_DEFERRED_INITIALIZER(NULL, 0, 0), \
133 }
134
135 #define DECLARE_WORK(n, f) \
136 struct work_struct n = __WORK_INITIALIZER(n, f)
137
138 #define DECLARE_DELAYED_WORK(n, f) \
139 struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f)
140
141 #define DECLARE_DEFERRED_WORK(n, f) \
142 struct delayed_work n = __DEFERRED_WORK_INITIALIZER(n, f)
143
144 /*
145 * initialize a work item's function pointer
146 */
147 #define PREPARE_WORK(_work, _func) \
148 do { \
149 (_work)->func = (_func); \
150 } while (0)
151
152 #define PREPARE_DELAYED_WORK(_work, _func) \
153 PREPARE_WORK(&(_work)->work, (_func))
154
155 #ifdef CONFIG_DEBUG_OBJECTS_WORK
156 extern void __init_work(struct work_struct *work, int onstack);
157 extern void destroy_work_on_stack(struct work_struct *work);
158 static inline unsigned int work_static(struct work_struct *work)
159 {
160 return *work_data_bits(work) & WORK_STRUCT_STATIC;
161 }
162 #else
163 static inline void __init_work(struct work_struct *work, int onstack) { }
164 static inline void destroy_work_on_stack(struct work_struct *work) { }
165 static inline unsigned int work_static(struct work_struct *work) { return 0; }
166 #endif
167
168 /*
169 * initialize all of a work item in one go
170 *
171 * NOTE! No point in using "atomic_long_set()": using a direct
172 * assignment of the work data initializer allows the compiler
173 * to generate better code.
174 */
175 #ifdef CONFIG_LOCKDEP
176 #define __INIT_WORK(_work, _func, _onstack) \
177 do { \
178 static struct lock_class_key __key; \
179 \
180 __init_work((_work), _onstack); \
181 (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
182 lockdep_init_map(&(_work)->lockdep_map, #_work, &__key, 0);\
183 INIT_LIST_HEAD(&(_work)->entry); \
184 PREPARE_WORK((_work), (_func)); \
185 } while (0)
186 #else
187 #define __INIT_WORK(_work, _func, _onstack) \
188 do { \
189 __init_work((_work), _onstack); \
190 (_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
191 INIT_LIST_HEAD(&(_work)->entry); \
192 PREPARE_WORK((_work), (_func)); \
193 } while (0)
194 #endif
195
196 #define INIT_WORK(_work, _func) \
197 do { \
198 __INIT_WORK((_work), (_func), 0); \
199 } while (0)
200
201 #define INIT_WORK_ONSTACK(_work, _func) \
202 do { \
203 __INIT_WORK((_work), (_func), 1); \
204 } while (0)
205
206 #define INIT_DELAYED_WORK(_work, _func) \
207 do { \
208 INIT_WORK(&(_work)->work, (_func)); \
209 init_timer(&(_work)->timer); \
210 } while (0)
211
212 #define INIT_DELAYED_WORK_ONSTACK(_work, _func) \
213 do { \
214 INIT_WORK_ONSTACK(&(_work)->work, (_func)); \
215 init_timer_on_stack(&(_work)->timer); \
216 } while (0)
217
218 #define INIT_DELAYED_WORK_DEFERRABLE(_work, _func) \
219 do { \
220 INIT_WORK(&(_work)->work, (_func)); \
221 init_timer_deferrable(&(_work)->timer); \
222 } while (0)
223
224 /**
225 * work_pending - Find out whether a work item is currently pending
226 * @work: The work item in question
227 */
228 #define work_pending(work) \
229 test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
230
231 /**
232 * delayed_work_pending - Find out whether a delayable work item is currently
233 * pending
234 * @work: The work item in question
235 */
236 #define delayed_work_pending(w) \
237 work_pending(&(w)->work)
238
239 /**
240 * work_clear_pending - for internal use only, mark a work item as not pending
241 * @work: The work item in question
242 */
243 #define work_clear_pending(work) \
244 clear_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
245
246 /*
247 * Workqueue flags and constants. For details, please refer to
248 * Documentation/workqueue.txt.
249 */
250 enum {
251 WQ_NON_REENTRANT = 1 << 0, /* guarantee non-reentrance */
252 WQ_UNBOUND = 1 << 1, /* not bound to any cpu */
253 WQ_FREEZABLE = 1 << 2, /* freeze during suspend */
254 WQ_MEM_RECLAIM = 1 << 3, /* may be used for memory reclaim */
255 WQ_HIGHPRI = 1 << 4, /* high priority */
256 WQ_CPU_INTENSIVE = 1 << 5, /* cpu instensive workqueue */
257
258 WQ_DRAINING = 1 << 6, /* internal: workqueue is draining */
259 WQ_RESCUER = 1 << 7, /* internal: workqueue has rescuer */
260
261 WQ_MAX_ACTIVE = 512, /* I like 512, better ideas? */
262 WQ_MAX_UNBOUND_PER_CPU = 4, /* 4 * #cpus for unbound wq */
263 WQ_DFL_ACTIVE = WQ_MAX_ACTIVE / 2,
264 };
265
266 /* unbound wq's aren't per-cpu, scale max_active according to #cpus */
267 #define WQ_UNBOUND_MAX_ACTIVE \
268 max_t(int, WQ_MAX_ACTIVE, num_possible_cpus() * WQ_MAX_UNBOUND_PER_CPU)
269
270 /*
271 * System-wide workqueues which are always present.
272 *
273 * system_wq is the one used by schedule[_delayed]_work[_on]().
274 * Multi-CPU multi-threaded. There are users which expect relatively
275 * short queue flush time. Don't queue works which can run for too
276 * long.
277 *
278 * system_long_wq is similar to system_wq but may host long running
279 * works. Queue flushing might take relatively long.
280 *
281 * system_nrt_wq is non-reentrant and guarantees that any given work
282 * item is never executed in parallel by multiple CPUs. Queue
283 * flushing might take relatively long.
284 *
285 * system_unbound_wq is unbound workqueue. Workers are not bound to
286 * any specific CPU, not concurrency managed, and all queued works are
287 * executed immediately as long as max_active limit is not reached and
288 * resources are available.
289 *
290 * system_freezable_wq is equivalent to system_wq except that it's
291 * freezable.
292 */
293 extern struct workqueue_struct *system_wq;
294 extern struct workqueue_struct *system_long_wq;
295 extern struct workqueue_struct *system_nrt_wq;
296 extern struct workqueue_struct *system_unbound_wq;
297 extern struct workqueue_struct *system_freezable_wq;
298
299 extern struct workqueue_struct *
300 __alloc_workqueue_key(const char *name, unsigned int flags, int max_active,
301 struct lock_class_key *key, const char *lock_name);
302
303 #ifdef CONFIG_LOCKDEP
304 #define alloc_workqueue(name, flags, max_active) \
305 ({ \
306 static struct lock_class_key __key; \
307 const char *__lock_name; \
308 \
309 if (__builtin_constant_p(name)) \
310 __lock_name = (name); \
311 else \
312 __lock_name = #name; \
313 \
314 __alloc_workqueue_key((name), (flags), (max_active), \
315 &__key, __lock_name); \
316 })
317 #else
318 #define alloc_workqueue(name, flags, max_active) \
319 __alloc_workqueue_key((name), (flags), (max_active), NULL, NULL)
320 #endif
321
322 /**
323 * alloc_ordered_workqueue - allocate an ordered workqueue
324 * @name: name of the workqueue
325 * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
326 *
327 * Allocate an ordered workqueue. An ordered workqueue executes at
328 * most one work item at any given time in the queued order. They are
329 * implemented as unbound workqueues with @max_active of one.
330 *
331 * RETURNS:
332 * Pointer to the allocated workqueue on success, %NULL on failure.
333 */
334 static inline struct workqueue_struct *
335 alloc_ordered_workqueue(const char *name, unsigned int flags)
336 {
337 return alloc_workqueue(name, WQ_UNBOUND | flags, 1);
338 }
339
340 #define create_workqueue(name) \
341 alloc_workqueue((name), WQ_MEM_RECLAIM, 1)
342 #define create_freezable_workqueue(name) \
343 alloc_workqueue((name), WQ_FREEZABLE | WQ_UNBOUND | WQ_MEM_RECLAIM, 1)
344 #define create_singlethread_workqueue(name) \
345 alloc_workqueue((name), WQ_UNBOUND | WQ_MEM_RECLAIM, 1)
346
347 extern void destroy_workqueue(struct workqueue_struct *wq);
348
349 extern int queue_work(struct workqueue_struct *wq, struct work_struct *work);
350 extern int queue_work_on(int cpu, struct workqueue_struct *wq,
351 struct work_struct *work);
352 extern int queue_delayed_work(struct workqueue_struct *wq,
353 struct delayed_work *work, unsigned long delay);
354 extern int queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
355 struct delayed_work *work, unsigned long delay);
356
357 extern void flush_workqueue(struct workqueue_struct *wq);
358 extern void drain_workqueue(struct workqueue_struct *wq);
359 extern void flush_scheduled_work(void);
360
361 extern int schedule_work(struct work_struct *work);
362 extern int schedule_work_on(int cpu, struct work_struct *work);
363 extern int schedule_delayed_work(struct delayed_work *work, unsigned long delay);
364 extern int schedule_delayed_work_on(int cpu, struct delayed_work *work,
365 unsigned long delay);
366 extern int schedule_on_each_cpu(work_func_t func);
367 extern int keventd_up(void);
368
369 int execute_in_process_context(work_func_t fn, struct execute_work *);
370
371 extern bool flush_work(struct work_struct *work);
372 extern bool flush_work_sync(struct work_struct *work);
373 extern bool cancel_work_sync(struct work_struct *work);
374
375 extern bool flush_delayed_work(struct delayed_work *dwork);
376 extern bool flush_delayed_work_sync(struct delayed_work *work);
377 extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
378
379 extern void workqueue_set_max_active(struct workqueue_struct *wq,
380 int max_active);
381 extern bool workqueue_congested(unsigned int cpu, struct workqueue_struct *wq);
382 extern unsigned int work_cpu(struct work_struct *work);
383 extern unsigned int work_busy(struct work_struct *work);
384
385 /*
386 * Kill off a pending schedule_delayed_work(). Note that the work callback
387 * function may still be running on return from cancel_delayed_work(), unless
388 * it returns 1 and the work doesn't re-arm itself. Run flush_workqueue() or
389 * cancel_work_sync() to wait on it.
390 */
391 static inline bool cancel_delayed_work(struct delayed_work *work)
392 {
393 bool ret;
394
395 ret = del_timer_sync(&work->timer);
396 if (ret)
397 work_clear_pending(&work->work);
398 return ret;
399 }
400
401 /*
402 * Like above, but uses del_timer() instead of del_timer_sync(). This means,
403 * if it returns 0 the timer function may be running and the queueing is in
404 * progress.
405 */
406 static inline bool __cancel_delayed_work(struct delayed_work *work)
407 {
408 bool ret;
409
410 ret = del_timer(&work->timer);
411 if (ret)
412 work_clear_pending(&work->work);
413 return ret;
414 }
415
416 #ifndef CONFIG_SMP
417 static inline long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg)
418 {
419 return fn(arg);
420 }
421 #else
422 long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg);
423 #endif /* CONFIG_SMP */
424
425 #ifdef CONFIG_FREEZER
426 extern void freeze_workqueues_begin(void);
427 extern bool freeze_workqueues_busy(void);
428 extern void thaw_workqueues(void);
429 #endif /* CONFIG_FREEZER */
430
431 #endif