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 <asm/atomic.h>
  13
  14 struct workqueue_struct;
  15
  16 struct work_struct;
  17 typedef void (*work_func_t)(struct work_struct *work);
  18
  19 /*
  20  * The first word is the work queue pointer and the flags rolled into
  21  * one
  22  */
  23 #define work_data_bits(work) ((unsigned long *)(&(work)->data))
  24
  25 enum {
  26         WORK_STRUCT_PENDING_BIT = 0,    /* work item is pending execution */
  27         WORK_STRUCT_LINKED_BIT  = 1,    /* next work is linked to this one */
  28 #ifdef CONFIG_DEBUG_OBJECTS_WORK
  29         WORK_STRUCT_STATIC_BIT  = 2,    /* static initializer (debugobjects) */
  30         WORK_STRUCT_COLOR_SHIFT = 3,    /* color for workqueue flushing */
  31 #else
  32         WORK_STRUCT_COLOR_SHIFT = 2,    /* color for workqueue flushing */
  33 #endif
  34
  35         WORK_STRUCT_COLOR_BITS  = 4,
  36
  37         WORK_STRUCT_PENDING     = 1 << WORK_STRUCT_PENDING_BIT,
  38         WORK_STRUCT_LINKED      = 1 << WORK_STRUCT_LINKED_BIT,
  39 #ifdef CONFIG_DEBUG_OBJECTS_WORK
  40         WORK_STRUCT_STATIC      = 1 << WORK_STRUCT_STATIC_BIT,
  41 #else
  42         WORK_STRUCT_STATIC      = 0,
  43 #endif
  44
  45         /*
  46          * The last color is no color used for works which don't
  47          * participate in workqueue flushing.
  48          */
  49         WORK_NR_COLORS          = (1 << WORK_STRUCT_COLOR_BITS) - 1,
  50         WORK_NO_COLOR           = WORK_NR_COLORS,
  51
  52         /*
  53          * Reserve 6 bits off of cwq pointer w/ debugobjects turned
  54          * off.  This makes cwqs aligned to 64 bytes which isn't too
  55          * excessive while allowing 15 workqueue flush colors.
  56          */
  57         WORK_STRUCT_FLAG_BITS   = WORK_STRUCT_COLOR_SHIFT +
  58                                   WORK_STRUCT_COLOR_BITS,
  59
  60         WORK_STRUCT_FLAG_MASK   = (1UL << WORK_STRUCT_FLAG_BITS) - 1,
  61         WORK_STRUCT_WQ_DATA_MASK = ~WORK_STRUCT_FLAG_MASK,
  62 };
  63
  64 struct work_struct {
  65         atomic_long_t data;
  66         struct list_head entry;
  67         work_func_t func;
  68 #ifdef CONFIG_LOCKDEP
  69         struct lockdep_map lockdep_map;
  70 #endif
  71 };
  72
  73 #define WORK_DATA_INIT()        ATOMIC_LONG_INIT(0)
  74 #define WORK_DATA_STATIC_INIT() ATOMIC_LONG_INIT(WORK_STRUCT_STATIC)
  75
  76 struct delayed_work {
  77         struct work_struct work;
  78         struct timer_list timer;
  79 };
  80
  81 static inline struct delayed_work *to_delayed_work(struct work_struct *work)
  82 {
  83         return container_of(work, struct delayed_work, work);
  84 }
  85
  86 struct execute_work {
  87         struct work_struct work;
  88 };
  89
  90 #ifdef CONFIG_LOCKDEP
  91 /*
  92  * NB: because we have to copy the lockdep_map, setting _key
  93  * here is required, otherwise it could get initialised to the
  94  * copy of the lockdep_map!
  95  */
  96 #define __WORK_INIT_LOCKDEP_MAP(n, k) \
  97         .lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k),
  98 #else
  99 #define __WORK_INIT_LOCKDEP_MAP(n, k)
 100 #endif
 101
 102 #define __WORK_INITIALIZER(n, f) {                              \
 103         .data = WORK_DATA_STATIC_INIT(),                        \
 104         .entry  = { &(n).entry, &(n).entry },                   \
 105         .func = (f),                                            \
 106         __WORK_INIT_LOCKDEP_MAP(#n, &(n))                       \
 107         }
 108
 109 #define __DELAYED_WORK_INITIALIZER(n, f) {                      \
 110         .work = __WORK_INITIALIZER((n).work, (f)),              \
 111         .timer = TIMER_INITIALIZER(NULL, 0, 0),                 \
 112         }
 113
 114 #define DECLARE_WORK(n, f)                                      \
 115         struct work_struct n = __WORK_INITIALIZER(n, f)
 116
 117 #define DECLARE_DELAYED_WORK(n, f)                              \
 118         struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f)
 119
 120 /*
 121  * initialize a work item's function pointer
 122  */
 123 #define PREPARE_WORK(_work, _func)                              \
 124         do {                                                    \
 125                 (_work)->func = (_func);                        \
 126         } while (0)
 127
 128 #define PREPARE_DELAYED_WORK(_work, _func)                      \
 129         PREPARE_WORK(&(_work)->work, (_func))
 130
 131 #ifdef CONFIG_DEBUG_OBJECTS_WORK
 132 extern void __init_work(struct work_struct *work, int onstack);
 133 extern void destroy_work_on_stack(struct work_struct *work);
 134 static inline unsigned int work_static(struct work_struct *work)
 135 {
 136         return *work_data_bits(work) & WORK_STRUCT_STATIC;
 137 }
 138 #else
 139 static inline void __init_work(struct work_struct *work, int onstack) { }
 140 static inline void destroy_work_on_stack(struct work_struct *work) { }
 141 static inline unsigned int work_static(struct work_struct *work) { return 0; }
 142 #endif
 143
 144 /*
 145  * initialize all of a work item in one go
 146  *
 147  * NOTE! No point in using "atomic_long_set()": using a direct
 148  * assignment of the work data initializer allows the compiler
 149  * to generate better code.
 150  */
 151 #ifdef CONFIG_LOCKDEP
 152 #define __INIT_WORK(_work, _func, _onstack)                             \
 153         do {                                                            \
 154                 static struct lock_class_key __key;                     \
 155                                                                         \
 156                 __init_work((_work), _onstack);                         \
 157                 (_work)->data = (atomic_long_t) WORK_DATA_INIT();       \
 158                 lockdep_init_map(&(_work)->lockdep_map, #_work, &__key, 0);\
 159                 INIT_LIST_HEAD(&(_work)->entry);                        \
 160                 PREPARE_WORK((_work), (_func));                         \
 161         } while (0)
 162 #else
 163 #define __INIT_WORK(_work, _func, _onstack)                             \
 164         do {                                                            \
 165                 __init_work((_work), _onstack);                         \
 166                 (_work)->data = (atomic_long_t) WORK_DATA_INIT();       \
 167                 INIT_LIST_HEAD(&(_work)->entry);                        \
 168                 PREPARE_WORK((_work), (_func));                         \
 169         } while (0)
 170 #endif
 171
 172 #define INIT_WORK(_work, _func)                                 \
 173         do {                                                    \
 174                 __INIT_WORK((_work), (_func), 0);               \
 175         } while (0)
 176
 177 #define INIT_WORK_ON_STACK(_work, _func)                        \
 178         do {                                                    \
 179                 __INIT_WORK((_work), (_func), 1);               \
 180         } while (0)
 181
 182 #define INIT_DELAYED_WORK(_work, _func)                         \
 183         do {                                                    \
 184                 INIT_WORK(&(_work)->work, (_func));             \
 185                 init_timer(&(_work)->timer);                    \
 186         } while (0)
 187
 188 #define INIT_DELAYED_WORK_ON_STACK(_work, _func)                \
 189         do {                                                    \
 190                 INIT_WORK_ON_STACK(&(_work)->work, (_func));    \
 191                 init_timer_on_stack(&(_work)->timer);           \
 192         } while (0)
 193
 194 #define INIT_DELAYED_WORK_DEFERRABLE(_work, _func)              \
 195         do {                                                    \
 196                 INIT_WORK(&(_work)->work, (_func));             \
 197                 init_timer_deferrable(&(_work)->timer);         \
 198         } while (0)
 199
 200 /**
 201  * work_pending - Find out whether a work item is currently pending
 202  * @work: The work item in question
 203  */
 204 #define work_pending(work) \
 205         test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
 206
 207 /**
 208  * delayed_work_pending - Find out whether a delayable work item is currently
 209  * pending
 210  * @work: The work item in question
 211  */
 212 #define delayed_work_pending(w) \
 213         work_pending(&(w)->work)
 214
 215 /**
 216  * work_clear_pending - for internal use only, mark a work item as not pending
 217  * @work: The work item in question
 218  */
 219 #define work_clear_pending(work) \
 220         clear_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))
 221
 222 enum {
 223         WQ_FREEZEABLE           = 1 << 0, /* freeze during suspend */
 224         WQ_SINGLE_CPU           = 1 << 1, /* only single cpu at a time */
 225 };
 226
 227 extern struct workqueue_struct *
 228 __create_workqueue_key(const char *name, unsigned int flags, int max_active,
 229                        struct lock_class_key *key, const char *lock_name);
 230
 231 #ifdef CONFIG_LOCKDEP
 232 #define __create_workqueue(name, flags, max_active)             \
 233 ({                                                              \
 234         static struct lock_class_key __key;                     \
 235         const char *__lock_name;                                \
 236                                                                 \
 237         if (__builtin_constant_p(name))                         \
 238                 __lock_name = (name);                           \
 239         else                                                    \
 240                 __lock_name = #name;                            \
 241                                                                 \
 242         __create_workqueue_key((name), (flags), (max_active),   \
 243                                 &__key, __lock_name);           \
 244 })
 245 #else
 246 #define __create_workqueue(name, flags, max_active)             \
 247         __create_workqueue_key((name), (flags), (max_active), NULL, NULL)
 248 #endif
 249
 250 #define create_workqueue(name)                                  \
 251         __create_workqueue((name), 0, 1)
 252 #define create_freezeable_workqueue(name)                       \
 253         __create_workqueue((name), WQ_FREEZEABLE | WQ_SINGLE_CPU, 1)
 254 #define create_singlethread_workqueue(name)                     \
 255         __create_workqueue((name), WQ_SINGLE_CPU, 1)
 256
 257 extern void destroy_workqueue(struct workqueue_struct *wq);
 258
 259 extern int queue_work(struct workqueue_struct *wq, struct work_struct *work);
 260 extern int queue_work_on(int cpu, struct workqueue_struct *wq,
 261                         struct work_struct *work);
 262 extern int queue_delayed_work(struct workqueue_struct *wq,
 263                         struct delayed_work *work, unsigned long delay);
 264 extern int queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
 265                         struct delayed_work *work, unsigned long delay);
 266
 267 extern void flush_workqueue(struct workqueue_struct *wq);
 268 extern void flush_scheduled_work(void);
 269 extern void flush_delayed_work(struct delayed_work *work);
 270
 271 extern int schedule_work(struct work_struct *work);
 272 extern int schedule_work_on(int cpu, struct work_struct *work);
 273 extern int schedule_delayed_work(struct delayed_work *work, unsigned long delay);
 274 extern int schedule_delayed_work_on(int cpu, struct delayed_work *work,
 275                                         unsigned long delay);
 276 extern int schedule_on_each_cpu(work_func_t func);
 277 extern int current_is_keventd(void);
 278 extern int keventd_up(void);
 279
 280 extern void init_workqueues(void);
 281 int execute_in_process_context(work_func_t fn, struct execute_work *);
 282
 283 extern int flush_work(struct work_struct *work);
 284
 285 extern int cancel_work_sync(struct work_struct *work);
 286
 287 /*
 288  * Kill off a pending schedule_delayed_work().  Note that the work callback
 289  * function may still be running on return from cancel_delayed_work(), unless
 290  * it returns 1 and the work doesn't re-arm itself. Run flush_workqueue() or
 291  * cancel_work_sync() to wait on it.
 292  */
 293 static inline int cancel_delayed_work(struct delayed_work *work)
 294 {
 295         int ret;
 296
 297         ret = del_timer_sync(&work->timer);
 298         if (ret)
 299                 work_clear_pending(&work->work);
 300         return ret;
 301 }
 302
 303 /*
 304  * Like above, but uses del_timer() instead of del_timer_sync(). This means,
 305  * if it returns 0 the timer function may be running and the queueing is in
 306  * progress.
 307  */
 308 static inline int __cancel_delayed_work(struct delayed_work *work)
 309 {
 310         int ret;
 311
 312         ret = del_timer(&work->timer);
 313         if (ret)
 314                 work_clear_pending(&work->work);
 315         return ret;
 316 }
 317
 318 extern int cancel_delayed_work_sync(struct delayed_work *work);
 319
 320 /* Obsolete. use cancel_delayed_work_sync() */
 321 static inline
 322 void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq,
 323                                         struct delayed_work *work)
 324 {
 325         cancel_delayed_work_sync(work);
 326 }
 327
 328 /* Obsolete. use cancel_delayed_work_sync() */
 329 static inline
 330 void cancel_rearming_delayed_work(struct delayed_work *work)
 331 {
 332         cancel_delayed_work_sync(work);
 333 }
 334
 335 #ifndef CONFIG_SMP
 336 static inline long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg)
 337 {
 338         return fn(arg);
 339 }
 340 #else
 341 long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg);
 342 #endif /* CONFIG_SMP */
 343
 344 #ifdef CONFIG_FREEZER
 345 extern void freeze_workqueues_begin(void);
 346 extern bool freeze_workqueues_busy(void);
 347 extern void thaw_workqueues(void);
 348 #endif /* CONFIG_FREEZER */
 349
 350 #endif