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
  12 struct workqueue_struct;
  13
  14 struct work_struct;
  15 typedef void (*work_func_t)(struct work_struct *work);
  16
  17 struct work_struct {
  18         /* the first word is the work queue pointer and the flags rolled into
  19          * one */
  20         unsigned long management;
  21 #define WORK_STRUCT_PENDING 0           /* T if work item pending execution */
  22 #define WORK_STRUCT_NOAUTOREL 1         /* F if work item automatically released on exec */
  23 #define WORK_STRUCT_FLAG_MASK (3UL)
  24 #define WORK_STRUCT_WQ_DATA_MASK (~WORK_STRUCT_FLAG_MASK)
  25         struct list_head entry;
  26         work_func_t func;
  27 };
  28
  29 struct delayed_work {
  30         struct work_struct work;
  31         struct timer_list timer;
  32 };
  33
  34 struct execute_work {
  35         struct work_struct work;
  36 };
  37
  38 #define __WORK_INITIALIZER(n, f) {                              \
  39         .management = 0,                                        \
  40         .entry  = { &(n).entry, &(n).entry },                   \
  41         .func = (f),                                            \
  42         }
  43
  44 #define __WORK_INITIALIZER_NAR(n, f) {                          \
  45         .management = (1 << WORK_STRUCT_NOAUTOREL),             \
  46         .entry  = { &(n).entry, &(n).entry },                   \
  47         .func = (f),                                            \
  48         }
  49
  50 #define __DELAYED_WORK_INITIALIZER(n, f) {                      \
  51         .work = __WORK_INITIALIZER((n).work, (f)),              \
  52         .timer = TIMER_INITIALIZER(NULL, 0, 0),                 \
  53         }
  54
  55 #define __DELAYED_WORK_INITIALIZER_NAR(n, f) {                  \
  56         .work = __WORK_INITIALIZER_NAR((n).work, (f)),          \
  57         .timer = TIMER_INITIALIZER(NULL, 0, 0),                 \
  58         }
  59
  60 #define DECLARE_WORK(n, f)                                      \
  61         struct work_struct n = __WORK_INITIALIZER(n, f)
  62
  63 #define DECLARE_WORK_NAR(n, f)                                  \
  64         struct work_struct n = __WORK_INITIALIZER_NAR(n, f)
  65
  66 #define DECLARE_DELAYED_WORK(n, f)                              \
  67         struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f)
  68
  69 #define DECLARE_DELAYED_WORK_NAR(n, f)                  \
  70         struct dwork_struct n = __DELAYED_WORK_INITIALIZER_NAR(n, f)
  71
  72 /*
  73  * initialize a work item's function pointer
  74  */
  75 #define PREPARE_WORK(_work, _func)                              \
  76         do {                                                    \
  77                 (_work)->func = (_func);                        \
  78         } while (0)
  79
  80 #define PREPARE_DELAYED_WORK(_work, _func)                      \
  81         PREPARE_WORK(&(_work)->work, (_func))
  82
  83 /*
  84  * initialize all of a work item in one go
  85  */
  86 #define INIT_WORK(_work, _func)                                 \
  87         do {                                                    \
  88                 (_work)->management = 0;                        \
  89                 INIT_LIST_HEAD(&(_work)->entry);                \
  90                 PREPARE_WORK((_work), (_func));                 \
  91         } while (0)
  92
  93 #define INIT_WORK_NAR(_work, _func)                                     \
  94         do {                                                            \
  95                 (_work)->management = (1 << WORK_STRUCT_NOAUTOREL);     \
  96                 INIT_LIST_HEAD(&(_work)->entry);                        \
  97                 PREPARE_WORK((_work), (_func));                         \
  98         } while (0)
  99
 100 #define INIT_DELAYED_WORK(_work, _func)                         \
 101         do {                                                    \
 102                 INIT_WORK(&(_work)->work, (_func));             \
 103                 init_timer(&(_work)->timer);                    \
 104         } while (0)
 105
 106 #define INIT_DELAYED_WORK_NAR(_work, _func)                     \
 107         do {                                                    \
 108                 INIT_WORK_NAR(&(_work)->work, (_func));         \
 109                 init_timer(&(_work)->timer);                    \
 110         } while (0)
 111
 112 /**
 113  * work_pending - Find out whether a work item is currently pending
 114  * @work: The work item in question
 115  */
 116 #define work_pending(work) \
 117         test_bit(WORK_STRUCT_PENDING, &(work)->management)
 118
 119 /**
 120  * delayed_work_pending - Find out whether a delayable work item is currently
 121  * pending
 122  * @work: The work item in question
 123  */
 124 #define delayed_work_pending(work) \
 125         test_bit(WORK_STRUCT_PENDING, &(work)->work.management)
 126
 127 /**
 128  * work_release - Release a work item under execution
 129  * @work: The work item to release
 130  *
 131  * This is used to release a work item that has been initialised with automatic
 132  * release mode disabled (WORK_STRUCT_NOAUTOREL is set).  This gives the work
 133  * function the opportunity to grab auxiliary data from the container of the
 134  * work_struct before clearing the pending bit as the work_struct may be
 135  * subject to deallocation the moment the pending bit is cleared.
 136  *
 137  * In such a case, this should be called in the work function after it has
 138  * fetched any data it may require from the containter of the work_struct.
 139  * After this function has been called, the work_struct may be scheduled for
 140  * further execution or it may be deallocated unless other precautions are
 141  * taken.
 142  *
 143  * This should also be used to release a delayed work item.
 144  */
 145 #define work_release(work) \
 146         clear_bit(WORK_STRUCT_PENDING, &(work)->management)
 147
 148
 149 extern struct workqueue_struct *__create_workqueue(const char *name,
 150                                                     int singlethread);
 151 #define create_workqueue(name) __create_workqueue((name), 0)
 152 #define create_singlethread_workqueue(name) __create_workqueue((name), 1)
 153
 154 extern void destroy_workqueue(struct workqueue_struct *wq);
 155
 156 extern int FASTCALL(queue_work(struct workqueue_struct *wq, struct work_struct *work));
 157 extern int FASTCALL(queue_delayed_work(struct workqueue_struct *wq, struct delayed_work *work, unsigned long delay));
 158 extern int queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
 159         struct delayed_work *work, unsigned long delay);
 160 extern void FASTCALL(flush_workqueue(struct workqueue_struct *wq));
 161
 162 extern int FASTCALL(schedule_work(struct work_struct *work));
 163 extern int FASTCALL(schedule_delayed_work(struct delayed_work *work, unsigned long delay));
 164
 165 extern int schedule_delayed_work_on(int cpu, struct delayed_work *work, unsigned long delay);
 166 extern int schedule_on_each_cpu(work_func_t func);
 167 extern void flush_scheduled_work(void);
 168 extern int current_is_keventd(void);
 169 extern int keventd_up(void);
 170
 171 extern void init_workqueues(void);
 172 void cancel_rearming_delayed_work(struct delayed_work *work);
 173 void cancel_rearming_delayed_workqueue(struct workqueue_struct *,
 174                                        struct delayed_work *);
 175 int execute_in_process_context(work_func_t fn, struct execute_work *);
 176
 177 /*
 178  * Kill off a pending schedule_delayed_work().  Note that the work callback
 179  * function may still be running on return from cancel_delayed_work().  Run
 180  * flush_scheduled_work() to wait on it.
 181  */
 182 static inline int cancel_delayed_work(struct delayed_work *work)
 183 {
 184         int ret;
 185
 186         ret = del_timer_sync(&work->timer);
 187         if (ret)
 188                 clear_bit(WORK_STRUCT_PENDING, &work->work.management);
 189         return ret;
 190 }
 191
 192 #endif