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