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 struct execute_work {
  45         struct work_struct work;
  46 };
  47
  48 #ifdef CONFIG_LOCKDEP
  49 /*
  50  * NB: because we have to copy the lockdep_map, setting _key
  51  * here is required, otherwise it could get initialised to the
  52  * copy of the lockdep_map!
  53  */
  54 #define __WORK_INIT_LOCKDEP_MAP(n, k) \
  55         .lockdep_map = STATIC_LOCKDEP_MAP_INIT(n, k),
  56 #else
  57 #define __WORK_INIT_LOCKDEP_MAP(n, k)
  58 #endif
  59
  60 #define __WORK_INITIALIZER(n, f) {                              \
  61         .data = WORK_DATA_INIT(),                               \
  62         .entry  = { &(n).entry, &(n).entry },                   \
  63         .func = (f),                                            \
  64         __WORK_INIT_LOCKDEP_MAP(#n, &(n))                       \
  65         }
  66
  67 #define __DELAYED_WORK_INITIALIZER(n, f) {                      \
  68         .work = __WORK_INITIALIZER((n).work, (f)),              \
  69         .timer = TIMER_INITIALIZER(NULL, 0, 0),                 \
  70         }
  71
  72 #define DECLARE_WORK(n, f)                                      \
  73         struct work_struct n = __WORK_INITIALIZER(n, f)
  74
  75 #define DECLARE_DELAYED_WORK(n, f)                              \
  76         struct delayed_work n = __DELAYED_WORK_INITIALIZER(n, f)
  77
  78 /*
  79  * initialize a work item's function pointer
  80  */
  81 #define PREPARE_WORK(_work, _func)                              \
  82         do {                                                    \
  83                 (_work)->func = (_func);                        \
  84         } while (0)
  85
  86 #define PREPARE_DELAYED_WORK(_work, _func)                      \
  87         PREPARE_WORK(&(_work)->work, (_func))
  88
  89 /*
  90  * initialize all of a work item in one go
  91  *
  92  * NOTE! No point in using "atomic_long_set()": useing a direct
  93  * assignment of the work data initializer allows the compiler
  94  * to generate better code.
  95  */
  96 #ifdef CONFIG_LOCKDEP
  97 #define INIT_WORK(_work, _func)                                         \
  98         do {                                                            \
  99                 static struct lock_class_key __key;                     \
 100                                                                         \
 101                 (_work)->data = (atomic_long_t) WORK_DATA_INIT();       \
 102                 lockdep_init_map(&(_work)->lockdep_map, #_work, &__key, 0);\
 103                 INIT_LIST_HEAD(&(_work)->entry);                        \
 104                 PREPARE_WORK((_work), (_func));                         \
 105         } while (0)
 106 #else
 107 #define INIT_WORK(_work, _func)                                         \
 108         do {                                                            \
 109                 (_work)->data = (atomic_long_t) WORK_DATA_INIT();       \
 110                 INIT_LIST_HEAD(&(_work)->entry);                        \
 111                 PREPARE_WORK((_work), (_func));                         \
 112         } while (0)
 113 #endif
 114
 115 #define INIT_DELAYED_WORK(_work, _func)                         \
 116         do {                                                    \
 117                 INIT_WORK(&(_work)->work, (_func));             \
 118                 init_timer(&(_work)->timer);                    \
 119         } while (0)
 120
 121 #define INIT_DELAYED_WORK_DEFERRABLE(_work, _func)                      \
 122         do {                                                    \
 123                 INIT_WORK(&(_work)->work, (_func));             \
 124                 init_timer_deferrable(&(_work)->timer);         \
 125         } while (0)
 126
 127 /**
 128  * work_pending - Find out whether a work item is currently pending
 129  * @work: The work item in question
 130  */
 131 #define work_pending(work) \
 132         test_bit(WORK_STRUCT_PENDING, work_data_bits(work))
 133
 134 /**
 135  * delayed_work_pending - Find out whether a delayable work item is currently
 136  * pending
 137  * @work: The work item in question
 138  */
 139 #define delayed_work_pending(w) \
 140         work_pending(&(w)->work)
 141
 142 /**
 143  * work_clear_pending - for internal use only, mark a work item as not pending
 144  * @work: The work item in question
 145  */
 146 #define work_clear_pending(work) \
 147         clear_bit(WORK_STRUCT_PENDING, work_data_bits(work))
 148
 149
 150 extern struct workqueue_struct *
 151 __create_workqueue_key(const char *name, int singlethread,
 152                        int freezeable, struct lock_class_key *key,
 153                        const char *lock_name);
 154
 155 #ifdef CONFIG_LOCKDEP
 156 #define __create_workqueue(name, singlethread, freezeable)      \
 157 ({                                                              \
 158         static struct lock_class_key __key;                     \
 159         const char *__lock_name;                                \
 160                                                                 \
 161         if (__builtin_constant_p(name))                         \
 162                 __lock_name = (name);                           \
 163         else                                                    \
 164                 __lock_name = #name;                            \
 165                                                                 \
 166         __create_workqueue_key((name), (singlethread),          \
 167                                (freezeable), &__key,            \
 168                                __lock_name);                    \
 169 })
 170 #else
 171 #define __create_workqueue(name, singlethread, freezeable)      \
 172         __create_workqueue_key((name), (singlethread), (freezeable), NULL, NULL)
 173 #endif
 174
 175 #define create_workqueue(name) __create_workqueue((name), 0, 0)
 176 #define create_freezeable_workqueue(name) __create_workqueue((name), 1, 1)
 177 #define create_singlethread_workqueue(name) __create_workqueue((name), 1, 0)
 178
 179 extern void destroy_workqueue(struct workqueue_struct *wq);
 180
 181 extern int queue_work(struct workqueue_struct *wq, struct work_struct *work);
 182 extern int queue_delayed_work(struct workqueue_struct *wq,
 183                         struct delayed_work *work, unsigned long delay);
 184 extern int queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
 185                         struct delayed_work *work, unsigned long delay);
 186
 187 extern void flush_workqueue(struct workqueue_struct *wq);
 188 extern void flush_scheduled_work(void);
 189
 190 extern int schedule_work(struct work_struct *work);
 191 extern int schedule_delayed_work(struct delayed_work *work, unsigned long delay);
 192 extern int schedule_delayed_work_on(int cpu, struct delayed_work *work,
 193                                         unsigned long delay);
 194 extern int schedule_on_each_cpu(work_func_t func);
 195 extern int current_is_keventd(void);
 196 extern int keventd_up(void);
 197
 198 extern void init_workqueues(void);
 199 int execute_in_process_context(work_func_t fn, struct execute_work *);
 200
 201 extern int cancel_work_sync(struct work_struct *work);
 202
 203 /*
 204  * Kill off a pending schedule_delayed_work().  Note that the work callback
 205  * function may still be running on return from cancel_delayed_work(), unless
 206  * it returns 1 and the work doesn't re-arm itself. Run flush_workqueue() or
 207  * cancel_work_sync() to wait on it.
 208  */
 209 static inline int cancel_delayed_work(struct delayed_work *work)
 210 {
 211         int ret;
 212
 213         ret = del_timer_sync(&work->timer);
 214         if (ret)
 215                 work_clear_pending(&work->work);
 216         return ret;
 217 }
 218
 219 extern int cancel_delayed_work_sync(struct delayed_work *work);
 220
 221 /* Obsolete. use cancel_delayed_work_sync() */
 222 static inline
 223 void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq,
 224                                         struct delayed_work *work)
 225 {
 226         cancel_delayed_work_sync(work);
 227 }
 228
 229 /* Obsolete. use cancel_delayed_work_sync() */
 230 static inline
 231 void cancel_rearming_delayed_work(struct delayed_work *work)
 232 {
 233         cancel_delayed_work_sync(work);
 234 }
 235
 236 #endif