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