228 lines
7.4 KiB
C
228 lines
7.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_TIMER_H
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#define _LINUX_TIMER_H
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#include <linux/list.h>
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#include <linux/ktime.h>
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#include <linux/stddef.h>
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#include <linux/debugobjects.h>
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#include <linux/stringify.h>
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struct timer_list {
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/*
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* All fields that change during normal runtime grouped to the
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* same cacheline
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*/
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struct hlist_node entry;
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unsigned long expires;
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void (*function)(struct timer_list *);
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u32 flags;
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#ifdef CONFIG_LOCKDEP
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struct lockdep_map lockdep_map;
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#endif
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};
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#ifdef CONFIG_LOCKDEP
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/*
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* NB: because we have to copy the lockdep_map, setting the lockdep_map key
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* (second argument) here is required, otherwise it could be initialised to
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* the copy of the lockdep_map later! We use the pointer to and the string
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* "<file>:<line>" as the key resp. the name of the lockdep_map.
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*/
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#define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn) \
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.lockdep_map = STATIC_LOCKDEP_MAP_INIT(_kn, &_kn),
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#else
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#define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn)
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#endif
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/**
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* @TIMER_DEFERRABLE: A deferrable timer will work normally when the
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* system is busy, but will not cause a CPU to come out of idle just
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* to service it; instead, the timer will be serviced when the CPU
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* eventually wakes up with a subsequent non-deferrable timer.
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*
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* @TIMER_IRQSAFE: An irqsafe timer is executed with IRQ disabled and
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* it's safe to wait for the completion of the running instance from
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* IRQ handlers, for example, by calling del_timer_sync().
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*
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* Note: The irq disabled callback execution is a special case for
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* workqueue locking issues. It's not meant for executing random crap
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* with interrupts disabled. Abuse is monitored!
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*
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* @TIMER_PINNED: A pinned timer will not be affected by any timer
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* placement heuristics (like, NOHZ) and will always expire on the CPU
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* on which the timer was enqueued.
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*
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* Note: Because enqueuing of timers can migrate the timer from one
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* CPU to another, pinned timers are not guaranteed to stay on the
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* initialy selected CPU. They move to the CPU on which the enqueue
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* function is invoked via mod_timer() or add_timer(). If the timer
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* should be placed on a particular CPU, then add_timer_on() has to be
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* used.
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*/
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#define TIMER_CPUMASK 0x0003FFFF
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#define TIMER_MIGRATING 0x00040000
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#define TIMER_BASEMASK (TIMER_CPUMASK | TIMER_MIGRATING)
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#define TIMER_DEFERRABLE 0x00080000
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#define TIMER_PINNED 0x00100000
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#define TIMER_IRQSAFE 0x00200000
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#define TIMER_INIT_FLAGS (TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
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#define TIMER_ARRAYSHIFT 22
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#define TIMER_ARRAYMASK 0xFFC00000
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#define TIMER_TRACE_FLAGMASK (TIMER_MIGRATING | TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
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#define __TIMER_INITIALIZER(_function, _flags) { \
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.entry = { .next = TIMER_ENTRY_STATIC }, \
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.function = (_function), \
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.flags = (_flags), \
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__TIMER_LOCKDEP_MAP_INITIALIZER( \
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__FILE__ ":" __stringify(__LINE__)) \
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}
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#define DEFINE_TIMER(_name, _function) \
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struct timer_list _name = \
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__TIMER_INITIALIZER(_function, 0)
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/*
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* LOCKDEP and DEBUG timer interfaces.
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*/
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void init_timer_key(struct timer_list *timer,
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void (*func)(struct timer_list *), unsigned int flags,
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const char *name, struct lock_class_key *key);
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#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
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extern void init_timer_on_stack_key(struct timer_list *timer,
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void (*func)(struct timer_list *),
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unsigned int flags, const char *name,
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struct lock_class_key *key);
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#else
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static inline void init_timer_on_stack_key(struct timer_list *timer,
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void (*func)(struct timer_list *),
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unsigned int flags,
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const char *name,
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struct lock_class_key *key)
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{
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init_timer_key(timer, func, flags, name, key);
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}
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#endif
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#ifdef CONFIG_LOCKDEP
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#define __init_timer(_timer, _fn, _flags) \
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do { \
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static struct lock_class_key __key; \
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init_timer_key((_timer), (_fn), (_flags), #_timer, &__key);\
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} while (0)
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#define __init_timer_on_stack(_timer, _fn, _flags) \
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do { \
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static struct lock_class_key __key; \
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init_timer_on_stack_key((_timer), (_fn), (_flags), \
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#_timer, &__key); \
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} while (0)
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#else
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#define __init_timer(_timer, _fn, _flags) \
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init_timer_key((_timer), (_fn), (_flags), NULL, NULL)
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#define __init_timer_on_stack(_timer, _fn, _flags) \
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init_timer_on_stack_key((_timer), (_fn), (_flags), NULL, NULL)
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#endif
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/**
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* timer_setup - prepare a timer for first use
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* @timer: the timer in question
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* @callback: the function to call when timer expires
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* @flags: any TIMER_* flags
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*
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* Regular timer initialization should use either DEFINE_TIMER() above,
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* or timer_setup(). For timers on the stack, timer_setup_on_stack() must
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* be used and must be balanced with a call to destroy_timer_on_stack().
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*/
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#define timer_setup(timer, callback, flags) \
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__init_timer((timer), (callback), (flags))
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#define timer_setup_on_stack(timer, callback, flags) \
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__init_timer_on_stack((timer), (callback), (flags))
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#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
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extern void destroy_timer_on_stack(struct timer_list *timer);
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#else
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static inline void destroy_timer_on_stack(struct timer_list *timer) { }
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#endif
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#define from_timer(var, callback_timer, timer_fieldname) \
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container_of(callback_timer, typeof(*var), timer_fieldname)
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/**
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* timer_pending - is a timer pending?
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* @timer: the timer in question
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*
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* timer_pending will tell whether a given timer is currently pending,
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* or not. Callers must ensure serialization wrt. other operations done
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* to this timer, eg. interrupt contexts, or other CPUs on SMP.
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*
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* return value: 1 if the timer is pending, 0 if not.
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*/
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static inline int timer_pending(const struct timer_list * timer)
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{
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return !hlist_unhashed_lockless(&timer->entry);
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}
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extern void add_timer_on(struct timer_list *timer, int cpu);
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extern int del_timer(struct timer_list * timer);
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extern int mod_timer(struct timer_list *timer, unsigned long expires);
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extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
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extern int timer_reduce(struct timer_list *timer, unsigned long expires);
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/*
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* The jiffies value which is added to now, when there is no timer
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* in the timer wheel:
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*/
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#define NEXT_TIMER_MAX_DELTA ((1UL << 30) - 1)
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extern void add_timer(struct timer_list *timer);
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extern int try_to_del_timer_sync(struct timer_list *timer);
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#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
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extern int del_timer_sync(struct timer_list *timer);
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#else
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# define del_timer_sync(t) del_timer(t)
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#endif
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#define del_singleshot_timer_sync(t) del_timer_sync(t)
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extern bool timer_curr_running(struct timer_list *timer);
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extern void init_timers(void);
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struct hrtimer;
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extern enum hrtimer_restart it_real_fn(struct hrtimer *);
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#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
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struct ctl_table;
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extern unsigned int sysctl_timer_migration;
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int timer_migration_handler(struct ctl_table *table, int write,
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void *buffer, size_t *lenp, loff_t *ppos);
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#endif
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unsigned long __round_jiffies(unsigned long j, int cpu);
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unsigned long __round_jiffies_relative(unsigned long j, int cpu);
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unsigned long round_jiffies(unsigned long j);
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unsigned long round_jiffies_relative(unsigned long j);
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unsigned long __round_jiffies_up(unsigned long j, int cpu);
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unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
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unsigned long round_jiffies_up(unsigned long j);
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unsigned long round_jiffies_up_relative(unsigned long j);
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#ifdef CONFIG_HOTPLUG_CPU
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int timers_prepare_cpu(unsigned int cpu);
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int timers_dead_cpu(unsigned int cpu);
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#else
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#define timers_prepare_cpu NULL
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#define timers_dead_cpu NULL
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#endif
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#endif
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