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 * system_nrt_freezable_wq is equivalent to system_nrt_wq except that 294 * it's freezable. 295 */ 296 extern struct workqueue_struct *system_wq; 297 extern struct workqueue_struct *system_long_wq; 298 extern struct workqueue_struct *system_nrt_wq; 299 extern struct workqueue_struct *system_unbound_wq; 300 extern struct workqueue_struct *system_freezable_wq; 301 extern struct workqueue_struct *system_nrt_freezable_wq; 302 303 extern struct workqueue_struct * 304 __alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active, 305 struct lock_class_key *key, const char *lock_name, ...) __printf(1, 6); 306 307 /** 308 * alloc_workqueue - allocate a workqueue 309 * @fmt: printf format for the name of the workqueue 310 * @flags: WQ_* flags 311 * @max_active: max in-flight work items, 0 for default 312 * @args: args for @fmt 313 * 314 * Allocate a workqueue with the specified parameters. For detailed 315 * information on WQ_* flags, please refer to Documentation/workqueue.txt. 316 * 317 * The __lock_name macro dance is to guarantee that single lock_class_key 318 * doesn't end up with different namesm, which isn't allowed by lockdep. 319 * 320 * RETURNS: 321 * Pointer to the allocated workqueue on success, %NULL on failure. 322 */ 323 #ifdef CONFIG_LOCKDEP 324 #define alloc_workqueue(fmt, flags, max_active, args...) \ 325 ({ \ 326 static struct lock_class_key __key; \ 327 const char *__lock_name; \ 328 \ 329 if (__builtin_constant_p(fmt)) \ 330 __lock_name = (fmt); \ 331 else \ 332 __lock_name = #fmt; \ 333 \ 334 __alloc_workqueue_key((fmt), (flags), (max_active), \ 335 &__key, __lock_name, ##args); \ 336 }) 337 #else 338 #define alloc_workqueue(fmt, flags, max_active, args...) \ 339 __alloc_workqueue_key((fmt), (flags), (max_active), \ 340 NULL, NULL, ##args) 341 #endif 342 343 /** 344 * alloc_ordered_workqueue - allocate an ordered workqueue 345 * @fmt: printf format for the name of the workqueue 346 * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful) 347 * @args: args for @fmt 348 * 349 * Allocate an ordered workqueue. An ordered workqueue executes at 350 * most one work item at any given time in the queued order. They are 351 * implemented as unbound workqueues with @max_active of one. 352 * 353 * RETURNS: 354 * Pointer to the allocated workqueue on success, %NULL on failure. 355 */ 356 #define alloc_ordered_workqueue(fmt, flags, args...) \ 357 alloc_workqueue(fmt, WQ_UNBOUND | (flags), 1, ##args) 358 359 #define create_workqueue(name) \ 360 alloc_workqueue((name), WQ_MEM_RECLAIM, 1) 361 #define create_freezable_workqueue(name) \ 362 alloc_workqueue((name), WQ_FREEZABLE | WQ_UNBOUND | WQ_MEM_RECLAIM, 1) 363 #define create_singlethread_workqueue(name) \ 364 alloc_workqueue((name), WQ_UNBOUND | WQ_MEM_RECLAIM, 1) 365 366 extern void destroy_workqueue(struct workqueue_struct *wq); 367 368 extern int queue_work(struct workqueue_struct *wq, struct work_struct *work); 369 extern int queue_work_on(int cpu, struct workqueue_struct *wq, 370 struct work_struct *work); 371 extern int queue_delayed_work(struct workqueue_struct *wq, 372 struct delayed_work *work, unsigned long delay); 373 extern int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, 374 struct delayed_work *work, unsigned long delay); 375 376 extern void flush_workqueue(struct workqueue_struct *wq); 377 extern void drain_workqueue(struct workqueue_struct *wq); 378 extern void flush_scheduled_work(void); 379 380 extern int schedule_work(struct work_struct *work); 381 extern int schedule_work_on(int cpu, struct work_struct *work); 382 extern int schedule_delayed_work(struct delayed_work *work, unsigned long delay); 383 extern int schedule_delayed_work_on(int cpu, struct delayed_work *work, 384 unsigned long delay); 385 extern int schedule_on_each_cpu(work_func_t func); 386 extern int keventd_up(void); 387 388 int execute_in_process_context(work_func_t fn, struct execute_work *); 389 390 extern bool flush_work(struct work_struct *work); 391 extern bool flush_work_sync(struct work_struct *work); 392 extern bool cancel_work_sync(struct work_struct *work); 393 394 extern bool flush_delayed_work(struct delayed_work *dwork); 395 extern bool flush_delayed_work_sync(struct delayed_work *work); 396 extern bool cancel_delayed_work_sync(struct delayed_work *dwork); 397 398 extern void workqueue_set_max_active(struct workqueue_struct *wq, 399 int max_active); 400 extern bool workqueue_congested(unsigned int cpu, struct workqueue_struct *wq); 401 extern unsigned int work_cpu(struct work_struct *work); 402 extern unsigned int work_busy(struct work_struct *work); 403 404 /* 405 * Kill off a pending schedule_delayed_work(). Note that the work callback 406 * function may still be running on return from cancel_delayed_work(), unless 407 * it returns 1 and the work doesn't re-arm itself. Run flush_workqueue() or 408 * cancel_work_sync() to wait on it. 409 */ 410 static inline bool cancel_delayed_work(struct delayed_work *work) 411 { 412 bool ret; 413 414 ret = del_timer_sync(&work->timer); 415 if (ret) 416 work_clear_pending(&work->work); 417 return ret; 418 } 419 420 /* 421 * Like above, but uses del_timer() instead of del_timer_sync(). This means, 422 * if it returns 0 the timer function may be running and the queueing is in 423 * progress. 424 */ 425 static inline bool __cancel_delayed_work(struct delayed_work *work) 426 { 427 bool ret; 428 429 ret = del_timer(&work->timer); 430 if (ret) 431 work_clear_pending(&work->work); 432 return ret; 433 } 434 435 #ifndef CONFIG_SMP 436 static inline long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg) 437 { 438 return fn(arg); 439 } 440 #else 441 long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg); 442 #endif /* CONFIG_SMP */ 443 444 #ifdef CONFIG_FREEZER 445 extern void freeze_workqueues_begin(void); 446 extern bool freeze_workqueues_busy(void); 447 extern void thaw_workqueues(void); 448 #endif /* CONFIG_FREEZER */ 449 450 #endif 451