LCOV - code coverage report
Current view: top level - include/linux - timer.h (source / functions) Hit Total Coverage
Test: landlock.info Lines: 5 6 83.3 %
Date: 2021-04-22 12:43:58 Functions: 0 0 -

          Line data    Source code
       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_INIT_FLAGS        (TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
      71             : #define TIMER_ARRAYSHIFT        22
      72             : #define TIMER_ARRAYMASK         0xFFC00000
      73             : 
      74             : #define TIMER_TRACE_FLAGMASK    (TIMER_MIGRATING | TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
      75             : 
      76             : #define __TIMER_INITIALIZER(_function, _flags) {                \
      77             :                 .entry = { .next = TIMER_ENTRY_STATIC },        \
      78             :                 .function = (_function),                        \
      79             :                 .flags = (_flags),                              \
      80             :                 __TIMER_LOCKDEP_MAP_INITIALIZER(                \
      81             :                         __FILE__ ":" __stringify(__LINE__))   \
      82             :         }
      83             : 
      84             : #define DEFINE_TIMER(_name, _function)                          \
      85             :         struct timer_list _name =                               \
      86             :                 __TIMER_INITIALIZER(_function, 0)
      87             : 
      88             : /*
      89             :  * LOCKDEP and DEBUG timer interfaces.
      90             :  */
      91             : void init_timer_key(struct timer_list *timer,
      92             :                     void (*func)(struct timer_list *), unsigned int flags,
      93             :                     const char *name, struct lock_class_key *key);
      94             : 
      95             : #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
      96             : extern void init_timer_on_stack_key(struct timer_list *timer,
      97             :                                     void (*func)(struct timer_list *),
      98             :                                     unsigned int flags, const char *name,
      99             :                                     struct lock_class_key *key);
     100             : #else
     101        4569 : static inline void init_timer_on_stack_key(struct timer_list *timer,
     102             :                                            void (*func)(struct timer_list *),
     103             :                                            unsigned int flags,
     104             :                                            const char *name,
     105             :                                            struct lock_class_key *key)
     106             : {
     107        9138 :         init_timer_key(timer, func, flags, name, key);
     108           0 : }
     109             : #endif
     110             : 
     111             : #ifdef CONFIG_LOCKDEP
     112             : #define __init_timer(_timer, _fn, _flags)                               \
     113             :         do {                                                            \
     114             :                 static struct lock_class_key __key;                     \
     115             :                 init_timer_key((_timer), (_fn), (_flags), #_timer, &__key);\
     116             :         } while (0)
     117             : 
     118             : #define __init_timer_on_stack(_timer, _fn, _flags)                      \
     119             :         do {                                                            \
     120             :                 static struct lock_class_key __key;                     \
     121             :                 init_timer_on_stack_key((_timer), (_fn), (_flags),      \
     122             :                                         #_timer, &__key);            \
     123             :         } while (0)
     124             : #else
     125             : #define __init_timer(_timer, _fn, _flags)                               \
     126             :         init_timer_key((_timer), (_fn), (_flags), NULL, NULL)
     127             : #define __init_timer_on_stack(_timer, _fn, _flags)                      \
     128             :         init_timer_on_stack_key((_timer), (_fn), (_flags), NULL, NULL)
     129             : #endif
     130             : 
     131             : /**
     132             :  * timer_setup - prepare a timer for first use
     133             :  * @timer: the timer in question
     134             :  * @callback: the function to call when timer expires
     135             :  * @flags: any TIMER_* flags
     136             :  *
     137             :  * Regular timer initialization should use either DEFINE_TIMER() above,
     138             :  * or timer_setup(). For timers on the stack, timer_setup_on_stack() must
     139             :  * be used and must be balanced with a call to destroy_timer_on_stack().
     140             :  */
     141             : #define timer_setup(timer, callback, flags)                     \
     142             :         __init_timer((timer), (callback), (flags))
     143             : 
     144             : #define timer_setup_on_stack(timer, callback, flags)            \
     145             :         __init_timer_on_stack((timer), (callback), (flags))
     146             : 
     147             : #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
     148             : extern void destroy_timer_on_stack(struct timer_list *timer);
     149             : #else
     150        4566 : static inline void destroy_timer_on_stack(struct timer_list *timer) { }
     151             : #endif
     152             : 
     153             : #define from_timer(var, callback_timer, timer_fieldname) \
     154             :         container_of(callback_timer, typeof(*var), timer_fieldname)
     155             : 
     156             : /**
     157             :  * timer_pending - is a timer pending?
     158             :  * @timer: the timer in question
     159             :  *
     160             :  * timer_pending will tell whether a given timer is currently pending,
     161             :  * or not. Callers must ensure serialization wrt. other operations done
     162             :  * to this timer, eg. interrupt contexts, or other CPUs on SMP.
     163             :  *
     164             :  * return value: 1 if the timer is pending, 0 if not.
     165             :  */
     166       16460 : static inline int timer_pending(const struct timer_list * timer)
     167             : {
     168       16451 :         return !hlist_unhashed_lockless(&timer->entry);
     169             : }
     170             : 
     171             : extern void add_timer_on(struct timer_list *timer, int cpu);
     172             : extern int del_timer(struct timer_list * timer);
     173             : extern int mod_timer(struct timer_list *timer, unsigned long expires);
     174             : extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
     175             : extern int timer_reduce(struct timer_list *timer, unsigned long expires);
     176             : 
     177             : /*
     178             :  * The jiffies value which is added to now, when there is no timer
     179             :  * in the timer wheel:
     180             :  */
     181             : #define NEXT_TIMER_MAX_DELTA    ((1UL << 30) - 1)
     182             : 
     183             : extern void add_timer(struct timer_list *timer);
     184             : 
     185             : extern int try_to_del_timer_sync(struct timer_list *timer);
     186             : 
     187             : #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
     188             :   extern int del_timer_sync(struct timer_list *timer);
     189             : #else
     190             : # define del_timer_sync(t)              del_timer(t)
     191             : #endif
     192             : 
     193             : #define del_singleshot_timer_sync(t) del_timer_sync(t)
     194             : 
     195             : extern bool timer_curr_running(struct timer_list *timer);
     196             : 
     197             : extern void init_timers(void);
     198             : struct hrtimer;
     199             : extern enum hrtimer_restart it_real_fn(struct hrtimer *);
     200             : 
     201             : #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
     202             : struct ctl_table;
     203             : 
     204             : extern unsigned int sysctl_timer_migration;
     205             : int timer_migration_handler(struct ctl_table *table, int write,
     206             :                             void *buffer, size_t *lenp, loff_t *ppos);
     207             : #endif
     208             : 
     209             : unsigned long __round_jiffies(unsigned long j, int cpu);
     210             : unsigned long __round_jiffies_relative(unsigned long j, int cpu);
     211             : unsigned long round_jiffies(unsigned long j);
     212             : unsigned long round_jiffies_relative(unsigned long j);
     213             : 
     214             : unsigned long __round_jiffies_up(unsigned long j, int cpu);
     215             : unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
     216             : unsigned long round_jiffies_up(unsigned long j);
     217             : unsigned long round_jiffies_up_relative(unsigned long j);
     218             : 
     219             : #ifdef CONFIG_HOTPLUG_CPU
     220             : int timers_prepare_cpu(unsigned int cpu);
     221             : int timers_dead_cpu(unsigned int cpu);
     222             : #else
     223             : #define timers_prepare_cpu      NULL
     224             : #define timers_dead_cpu         NULL
     225             : #endif
     226             : 
     227             : #endif

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