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       1                 :            : /* SPDX-License-Identifier: GPL-2.0 */
       2                 :            : #ifndef _LINUX_TIMER_H
       3                 :            : #define _LINUX_TIMER_H
       4                 :            : 
       5                 :            : #include <linux/list.h>
       6                 :            : #include <linux/ktime.h>
       7                 :            : #include <linux/stddef.h>
       8                 :            : #include <linux/debugobjects.h>
       9                 :            : #include <linux/stringify.h>
      10                 :            : 
      11                 :            : struct timer_list {
      12                 :            :         /*
      13                 :            :          * All fields that change during normal runtime grouped to the
      14                 :            :          * same cacheline
      15                 :            :          */
      16                 :            :         struct hlist_node       entry;
      17                 :            :         unsigned long           expires;
      18                 :            :         void                    (*function)(struct timer_list *);
      19                 :            :         u32                     flags;
      20                 :            : 
      21                 :            : #ifdef CONFIG_LOCKDEP
      22                 :            :         struct lockdep_map      lockdep_map;
      23                 :            : #endif
      24                 :            : };
      25                 :            : 
      26                 :            : #ifdef CONFIG_LOCKDEP
      27                 :            : /*
      28                 :            :  * NB: because we have to copy the lockdep_map, setting the lockdep_map key
      29                 :            :  * (second argument) here is required, otherwise it could be initialised to
      30                 :            :  * the copy of the lockdep_map later! We use the pointer to and the string
      31                 :            :  * "<file>:<line>" as the key resp. the name of the lockdep_map.
      32                 :            :  */
      33                 :            : #define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn)                            \
      34                 :            :         .lockdep_map = STATIC_LOCKDEP_MAP_INIT(_kn, &_kn),
      35                 :            : #else
      36                 :            : #define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn)
      37                 :            : #endif
      38                 :            : 
      39                 :            : /**
      40                 :            :  * @TIMER_DEFERRABLE: A deferrable timer will work normally when the
      41                 :            :  * system is busy, but will not cause a CPU to come out of idle just
      42                 :            :  * to service it; instead, the timer will be serviced when the CPU
      43                 :            :  * eventually wakes up with a subsequent non-deferrable timer.
      44                 :            :  *
      45                 :            :  * @TIMER_IRQSAFE: An irqsafe timer is executed with IRQ disabled and
      46                 :            :  * it's safe to wait for the completion of the running instance from
      47                 :            :  * IRQ handlers, for example, by calling del_timer_sync().
      48                 :            :  *
      49                 :            :  * Note: The irq disabled callback execution is a special case for
      50                 :            :  * workqueue locking issues. It's not meant for executing random crap
      51                 :            :  * with interrupts disabled. Abuse is monitored!
      52                 :            :  *
      53                 :            :  * @TIMER_PINNED: A pinned timer will not be affected by any timer
      54                 :            :  * placement heuristics (like, NOHZ) and will always expire on the CPU
      55                 :            :  * on which the timer was enqueued.
      56                 :            :  *
      57                 :            :  * Note: Because enqueuing of timers can migrate the timer from one
      58                 :            :  * CPU to another, pinned timers are not guaranteed to stay on the
      59                 :            :  * initialy selected CPU.  They move to the CPU on which the enqueue
      60                 :            :  * function is invoked via mod_timer() or add_timer().  If the timer
      61                 :            :  * should be placed on a particular CPU, then add_timer_on() has to be
      62                 :            :  * used.
      63                 :            :  */
      64                 :            : #define TIMER_CPUMASK           0x0003FFFF
      65                 :            : #define TIMER_MIGRATING         0x00040000
      66                 :            : #define TIMER_BASEMASK          (TIMER_CPUMASK | TIMER_MIGRATING)
      67                 :            : #define TIMER_DEFERRABLE        0x00080000
      68                 :            : #define TIMER_PINNED            0x00100000
      69                 :            : #define TIMER_IRQSAFE           0x00200000
      70                 :            : #define TIMER_ARRAYSHIFT        22
      71                 :            : #define TIMER_ARRAYMASK         0xFFC00000
      72                 :            : 
      73                 :            : #define TIMER_TRACE_FLAGMASK    (TIMER_MIGRATING | TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
      74                 :            : 
      75                 :            : #define __TIMER_INITIALIZER(_function, _flags) {                \
      76                 :            :                 .entry = { .next = TIMER_ENTRY_STATIC },        \
      77                 :            :                 .function = (_function),                        \
      78                 :            :                 .flags = (_flags),                              \
      79                 :            :                 __TIMER_LOCKDEP_MAP_INITIALIZER(                \
      80                 :            :                         __FILE__ ":" __stringify(__LINE__))   \
      81                 :            :         }
      82                 :            : 
      83                 :            : #define DEFINE_TIMER(_name, _function)                          \
      84                 :            :         struct timer_list _name =                               \
      85                 :            :                 __TIMER_INITIALIZER(_function, 0)
      86                 :            : 
      87                 :            : /*
      88                 :            :  * LOCKDEP and DEBUG timer interfaces.
      89                 :            :  */
      90                 :            : void init_timer_key(struct timer_list *timer,
      91                 :            :                     void (*func)(struct timer_list *), unsigned int flags,
      92                 :            :                     const char *name, struct lock_class_key *key);
      93                 :            : 
      94                 :            : #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
      95                 :            : extern void init_timer_on_stack_key(struct timer_list *timer,
      96                 :            :                                     void (*func)(struct timer_list *),
      97                 :            :                                     unsigned int flags, const char *name,
      98                 :            :                                     struct lock_class_key *key);
      99                 :            : #else
     100                 :            : static inline void init_timer_on_stack_key(struct timer_list *timer,
     101                 :            :                                            void (*func)(struct timer_list *),
     102                 :            :                                            unsigned int flags,
     103                 :            :                                            const char *name,
     104                 :            :                                            struct lock_class_key *key)
     105                 :            : {
     106                 :          0 :         init_timer_key(timer, func, flags, name, key);
     107                 :            : }
     108                 :            : #endif
     109                 :            : 
     110                 :            : #ifdef CONFIG_LOCKDEP
     111                 :            : #define __init_timer(_timer, _fn, _flags)                               \
     112                 :            :         do {                                                            \
     113                 :            :                 static struct lock_class_key __key;                     \
     114                 :            :                 init_timer_key((_timer), (_fn), (_flags), #_timer, &__key);\
     115                 :            :         } while (0)
     116                 :            : 
     117                 :            : #define __init_timer_on_stack(_timer, _fn, _flags)                      \
     118                 :            :         do {                                                            \
     119                 :            :                 static struct lock_class_key __key;                     \
     120                 :            :                 init_timer_on_stack_key((_timer), (_fn), (_flags),      \
     121                 :            :                                         #_timer, &__key);            \
     122                 :            :         } while (0)
     123                 :            : #else
     124                 :            : #define __init_timer(_timer, _fn, _flags)                               \
     125                 :            :         init_timer_key((_timer), (_fn), (_flags), NULL, NULL)
     126                 :            : #define __init_timer_on_stack(_timer, _fn, _flags)                      \
     127                 :            :         init_timer_on_stack_key((_timer), (_fn), (_flags), NULL, NULL)
     128                 :            : #endif
     129                 :            : 
     130                 :            : /**
     131                 :            :  * timer_setup - prepare a timer for first use
     132                 :            :  * @timer: the timer in question
     133                 :            :  * @callback: the function to call when timer expires
     134                 :            :  * @flags: any TIMER_* flags
     135                 :            :  *
     136                 :            :  * Regular timer initialization should use either DEFINE_TIMER() above,
     137                 :            :  * or timer_setup(). For timers on the stack, timer_setup_on_stack() must
     138                 :            :  * be used and must be balanced with a call to destroy_timer_on_stack().
     139                 :            :  */
     140                 :            : #define timer_setup(timer, callback, flags)                     \
     141                 :            :         __init_timer((timer), (callback), (flags))
     142                 :            : 
     143                 :            : #define timer_setup_on_stack(timer, callback, flags)            \
     144                 :            :         __init_timer_on_stack((timer), (callback), (flags))
     145                 :            : 
     146                 :            : #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
     147                 :            : extern void destroy_timer_on_stack(struct timer_list *timer);
     148                 :            : #else
     149                 :            : static inline void destroy_timer_on_stack(struct timer_list *timer) { }
     150                 :            : #endif
     151                 :            : 
     152                 :            : #define from_timer(var, callback_timer, timer_fieldname) \
     153                 :            :         container_of(callback_timer, typeof(*var), timer_fieldname)
     154                 :            : 
     155                 :            : /**
     156                 :            :  * timer_pending - is a timer pending?
     157                 :            :  * @timer: the timer in question
     158                 :            :  *
     159                 :            :  * timer_pending will tell whether a given timer is currently pending,
     160                 :            :  * or not. Callers must ensure serialization wrt. other operations done
     161                 :            :  * to this timer, eg. interrupt contexts, or other CPUs on SMP.
     162                 :            :  *
     163                 :            :  * return value: 1 if the timer is pending, 0 if not.
     164                 :            :  */
     165                 :            : static inline int timer_pending(const struct timer_list * timer)
     166                 :            : {
     167                 :          3 :         return timer->entry.pprev != NULL;
     168                 :            : }
     169                 :            : 
     170                 :            : extern void add_timer_on(struct timer_list *timer, int cpu);
     171                 :            : extern int del_timer(struct timer_list * timer);
     172                 :            : extern int mod_timer(struct timer_list *timer, unsigned long expires);
     173                 :            : extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
     174                 :            : extern int timer_reduce(struct timer_list *timer, unsigned long expires);
     175                 :            : 
     176                 :            : /*
     177                 :            :  * The jiffies value which is added to now, when there is no timer
     178                 :            :  * in the timer wheel:
     179                 :            :  */
     180                 :            : #define NEXT_TIMER_MAX_DELTA    ((1UL << 30) - 1)
     181                 :            : 
     182                 :            : extern void add_timer(struct timer_list *timer);
     183                 :            : 
     184                 :            : extern int try_to_del_timer_sync(struct timer_list *timer);
     185                 :            : 
     186                 :            : #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
     187                 :            :   extern int del_timer_sync(struct timer_list *timer);
     188                 :            : #else
     189                 :            : # define del_timer_sync(t)              del_timer(t)
     190                 :            : #endif
     191                 :            : 
     192                 :            : #define del_singleshot_timer_sync(t) del_timer_sync(t)
     193                 :            : 
     194                 :            : extern void init_timers(void);
     195                 :            : extern void run_local_timers(void);
     196                 :            : struct hrtimer;
     197                 :            : extern enum hrtimer_restart it_real_fn(struct hrtimer *);
     198                 :            : 
     199                 :            : #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
     200                 :            : struct ctl_table;
     201                 :            : 
     202                 :            : extern unsigned int sysctl_timer_migration;
     203                 :            : int timer_migration_handler(struct ctl_table *table, int write,
     204                 :            :                             void __user *buffer, size_t *lenp,
     205                 :            :                             loff_t *ppos);
     206                 :            : #endif
     207                 :            : 
     208                 :            : unsigned long __round_jiffies(unsigned long j, int cpu);
     209                 :            : unsigned long __round_jiffies_relative(unsigned long j, int cpu);
     210                 :            : unsigned long round_jiffies(unsigned long j);
     211                 :            : unsigned long round_jiffies_relative(unsigned long j);
     212                 :            : 
     213                 :            : unsigned long __round_jiffies_up(unsigned long j, int cpu);
     214                 :            : unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
     215                 :            : unsigned long round_jiffies_up(unsigned long j);
     216                 :            : unsigned long round_jiffies_up_relative(unsigned long j);
     217                 :            : 
     218                 :            : #ifdef CONFIG_HOTPLUG_CPU
     219                 :            : int timers_prepare_cpu(unsigned int cpu);
     220                 :            : int timers_dead_cpu(unsigned int cpu);
     221                 :            : #else
     222                 :            : #define timers_prepare_cpu      NULL
     223                 :            : #define timers_dead_cpu         NULL
     224                 :            : #endif
     225                 :            : 
     226                 :            : #endif