include/linux/workqueue.h

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