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