include/linux/timer.h

   1 #ifndef _LINUX_TIMER_H
   2 #define _LINUX_TIMER_H
   3
   4 #include <linux/list.h>
   5 #include <linux/ktime.h>
   6 #include <linux/stddef.h>
   7 #include <linux/debugobjects.h>
   8 #include <linux/stringify.h>
   9
  10 struct tvec_base;
  11
  12 struct timer_list {
  13         /*
  14          * All fields that change during normal runtime grouped to the
  15          * same cacheline
  16          */
  17         struct hlist_node       entry;
  18         unsigned long           expires;
  19         void                    (*function)(unsigned long);
  20         unsigned long           data;
  21         u32                     flags;
  22
  23 #ifdef CONFIG_LOCKDEP
  24         struct lockdep_map      lockdep_map;
  25 #endif
  26 };
  27
  28 #ifdef CONFIG_LOCKDEP
  29 /*
  30  * NB: because we have to copy the lockdep_map, setting the lockdep_map key
  31  * (second argument) here is required, otherwise it could be initialised to
  32  * the copy of the lockdep_map later! We use the pointer to and the string
  33  * "<file>:<line>" as the key resp. the name of the lockdep_map.
  34  */
  35 #define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn)                            \
  36         .lockdep_map = STATIC_LOCKDEP_MAP_INIT(_kn, &_kn),
  37 #else
  38 #define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn)
  39 #endif
  40
  41 /*
  42  * A deferrable timer will work normally when the system is busy, but
  43  * will not cause a CPU to come out of idle just to service it; instead,
  44  * the timer will be serviced when the CPU eventually wakes up with a
  45  * subsequent non-deferrable timer.
  46  *
  47  * An irqsafe timer is executed with IRQ disabled and it's safe to wait for
  48  * the completion of the running instance from IRQ handlers, for example,
  49  * by calling del_timer_sync().
  50  *
  51  * Note: The irq disabled callback execution is a special case for
  52  * workqueue locking issues. It's not meant for executing random crap
  53  * with interrupts disabled. Abuse is monitored!
  54  */
  55 #define TIMER_CPUMASK           0x0003FFFF
  56 #define TIMER_MIGRATING         0x00040000
  57 #define TIMER_BASEMASK          (TIMER_CPUMASK | TIMER_MIGRATING)
  58 #define TIMER_DEFERRABLE        0x00080000
  59 #define TIMER_PINNED            0x00100000
  60 #define TIMER_IRQSAFE           0x00200000
  61 #define TIMER_ARRAYSHIFT        22
  62 #define TIMER_ARRAYMASK         0xFFC00000
  63
  64 #define TIMER_TRACE_FLAGMASK    (TIMER_MIGRATING | TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
  65
  66 #define TIMER_DATA_TYPE         unsigned long
  67 #define TIMER_FUNC_TYPE         void (*)(TIMER_DATA_TYPE)
  68
  69 #define __TIMER_INITIALIZER(_function, _data, _flags) {         \
  70                 .entry = { .next = TIMER_ENTRY_STATIC },        \
  71                 .function = (_function),                        \
  72                 .data = (_data),                                \
  73                 .flags = (_flags),                              \
  74                 __TIMER_LOCKDEP_MAP_INITIALIZER(                \
  75                         __FILE__ ":" __stringify(__LINE__))     \
  76         }
  77
  78 #define DEFINE_TIMER(_name, _function)                          \
  79         struct timer_list _name =                               \
  80                 __TIMER_INITIALIZER((TIMER_FUNC_TYPE)_function, 0, 0)
  81
  82 void init_timer_key(struct timer_list *timer, unsigned int flags,
  83                     const char *name, struct lock_class_key *key);
  84
  85 #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
  86 extern void init_timer_on_stack_key(struct timer_list *timer,
  87                                     unsigned int flags, const char *name,
  88                                     struct lock_class_key *key);
  89 extern void destroy_timer_on_stack(struct timer_list *timer);
  90 #else
  91 static inline void destroy_timer_on_stack(struct timer_list *timer) { }
  92 static inline void init_timer_on_stack_key(struct timer_list *timer,
  93                                            unsigned int flags, const char *name,
  94                                            struct lock_class_key *key)
  95 {
  96         init_timer_key(timer, flags, name, key);
  97 }
  98 #endif
  99
 100 #ifdef CONFIG_LOCKDEP
 101 #define __init_timer(_timer, _flags)                                    \
 102         do {                                                            \
 103                 static struct lock_class_key __key;                     \
 104                 init_timer_key((_timer), (_flags), #_timer, &__key);    \
 105         } while (0)
 106
 107 #define __init_timer_on_stack(_timer, _flags)                           \
 108         do {                                                            \
 109                 static struct lock_class_key __key;                     \
 110                 init_timer_on_stack_key((_timer), (_flags), #_timer, &__key); \
 111         } while (0)
 112 #else
 113 #define __init_timer(_timer, _flags)                                    \
 114         init_timer_key((_timer), (_flags), NULL, NULL)
 115 #define __init_timer_on_stack(_timer, _flags)                           \
 116         init_timer_on_stack_key((_timer), (_flags), NULL, NULL)
 117 #endif
 118
 119 #define init_timer(timer)                                               \
 120         __init_timer((timer), 0)
 121
 122 #define __setup_timer(_timer, _fn, _data, _flags)                       \
 123         do {                                                            \
 124                 __init_timer((_timer), (_flags));                       \
 125                 (_timer)->function = (_fn);                             \
 126                 (_timer)->data = (_data);                               \
 127         } while (0)
 128
 129 #define __setup_timer_on_stack(_timer, _fn, _data, _flags)              \
 130         do {                                                            \
 131                 __init_timer_on_stack((_timer), (_flags));              \
 132                 (_timer)->function = (_fn);                             \
 133                 (_timer)->data = (_data);                               \
 134         } while (0)
 135
 136 #define setup_timer(timer, fn, data)                                    \
 137         __setup_timer((timer), (fn), (data), 0)
 138 #define setup_pinned_timer(timer, fn, data)                             \
 139         __setup_timer((timer), (fn), (data), TIMER_PINNED)
 140 #define setup_deferrable_timer(timer, fn, data)                         \
 141         __setup_timer((timer), (fn), (data), TIMER_DEFERRABLE)
 142 #define setup_pinned_deferrable_timer(timer, fn, data)                  \
 143         __setup_timer((timer), (fn), (data), TIMER_DEFERRABLE | TIMER_PINNED)
 144 #define setup_timer_on_stack(timer, fn, data)                           \
 145         __setup_timer_on_stack((timer), (fn), (data), 0)
 146 #define setup_pinned_timer_on_stack(timer, fn, data)                    \
 147         __setup_timer_on_stack((timer), (fn), (data), TIMER_PINNED)
 148 #define setup_deferrable_timer_on_stack(timer, fn, data)                \
 149         __setup_timer_on_stack((timer), (fn), (data), TIMER_DEFERRABLE)
 150 #define setup_pinned_deferrable_timer_on_stack(timer, fn, data)         \
 151         __setup_timer_on_stack((timer), (fn), (data), TIMER_DEFERRABLE | TIMER_PINNED)
 152
 153 #ifndef CONFIG_LOCKDEP
 154 static inline void timer_setup(struct timer_list *timer,
 155                                void (*callback)(struct timer_list *),
 156                                unsigned int flags)
 157 {
 158         __setup_timer(timer, (TIMER_FUNC_TYPE)callback,
 159                       (TIMER_DATA_TYPE)timer, flags);
 160 }
 161
 162 static inline void timer_setup_on_stack(struct timer_list *timer,
 163                                void (*callback)(struct timer_list *),
 164                                unsigned int flags)
 165 {
 166         __setup_timer_on_stack(timer, (TIMER_FUNC_TYPE)callback,
 167                                (TIMER_DATA_TYPE)timer, flags);
 168 }
 169 #else
 170 /*
 171  * Under LOCKDEP, the timer lock_class_key (set up in __init_timer) needs
 172  * to be tied to the caller's context, so an inline (above) won't work. We
 173  * do want to keep the inline for argument type checking, though.
 174  */
 175 # define timer_setup(timer, callback, flags)                            \
 176                 __setup_timer((timer), (TIMER_FUNC_TYPE)(callback),     \
 177                               (TIMER_DATA_TYPE)(timer), (flags))
 178 # define timer_setup_on_stack(timer, callback, flags)                   \
 179                 __setup_timer_on_stack((timer),                         \
 180                                        (TIMER_FUNC_TYPE)(callback),     \
 181                                        (TIMER_DATA_TYPE)(timer), (flags))
 182 #endif
 183
 184 #define from_timer(var, callback_timer, timer_fieldname) \
 185         container_of(callback_timer, typeof(*var), timer_fieldname)
 186
 187 /**
 188  * timer_pending - is a timer pending?
 189  * @timer: the timer in question
 190  *
 191  * timer_pending will tell whether a given timer is currently pending,
 192  * or not. Callers must ensure serialization wrt. other operations done
 193  * to this timer, eg. interrupt contexts, or other CPUs on SMP.
 194  *
 195  * return value: 1 if the timer is pending, 0 if not.
 196  */
 197 static inline int timer_pending(const struct timer_list * timer)
 198 {
 199         return timer->entry.pprev != NULL;
 200 }
 201
 202 extern void add_timer_on(struct timer_list *timer, int cpu);
 203 extern int del_timer(struct timer_list * timer);
 204 extern int mod_timer(struct timer_list *timer, unsigned long expires);
 205 extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
 206 extern int timer_reduce(struct timer_list *timer, unsigned long expires);
 207
 208 /*
 209  * The jiffies value which is added to now, when there is no timer
 210  * in the timer wheel:
 211  */
 212 #define NEXT_TIMER_MAX_DELTA    ((1UL << 30) - 1)
 213
 214 extern void add_timer(struct timer_list *timer);
 215
 216 extern int try_to_del_timer_sync(struct timer_list *timer);
 217
 218 #ifdef CONFIG_SMP
 219   extern int del_timer_sync(struct timer_list *timer);
 220 #else
 221 # define del_timer_sync(t)              del_timer(t)
 222 #endif
 223
 224 #define del_singleshot_timer_sync(t) del_timer_sync(t)
 225
 226 extern void init_timers(void);
 227 extern void run_local_timers(void);
 228 struct hrtimer;
 229 extern enum hrtimer_restart it_real_fn(struct hrtimer *);
 230
 231 #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
 232 struct ctl_table;
 233
 234 extern unsigned int sysctl_timer_migration;
 235 int timer_migration_handler(struct ctl_table *table, int write,
 236                             void __user *buffer, size_t *lenp,
 237                             loff_t *ppos);
 238 #endif
 239
 240 unsigned long __round_jiffies(unsigned long j, int cpu);
 241 unsigned long __round_jiffies_relative(unsigned long j, int cpu);
 242 unsigned long round_jiffies(unsigned long j);
 243 unsigned long round_jiffies_relative(unsigned long j);
 244
 245 unsigned long __round_jiffies_up(unsigned long j, int cpu);
 246 unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
 247 unsigned long round_jiffies_up(unsigned long j);
 248 unsigned long round_jiffies_up_relative(unsigned long j);
 249
 250 #ifdef CONFIG_HOTPLUG_CPU
 251 int timers_dead_cpu(unsigned int cpu);
 252 #else
 253 #define timers_dead_cpu NULL
 254 #endif
 255
 256 #endif