projects/linux·blob v4.20-rc2 · refs

215 lines · 6.7 KiB

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
11struct 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 * A deferrable timer will work normally when the system is busy, but
41 * will not cause a CPU to come out of idle just to service it; instead,
42 * the timer will be serviced when the CPU eventually wakes up with a
43 * subsequent non-deferrable timer.
44 *
45 * An irqsafe timer is executed with IRQ disabled and it's safe to wait for
46 * the completion of the running instance from IRQ handlers, for example,
47 * 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#define TIMER_CPUMASK 0x0003FFFF
54#define TIMER_MIGRATING 0x00040000
55#define TIMER_BASEMASK (TIMER_CPUMASK | TIMER_MIGRATING)
56#define TIMER_DEFERRABLE 0x00080000
57#define TIMER_PINNED 0x00100000
58#define TIMER_IRQSAFE 0x00200000
59#define TIMER_ARRAYSHIFT 22
60#define TIMER_ARRAYMASK 0xFFC00000
61
62#define TIMER_TRACE_FLAGMASK (TIMER_MIGRATING | TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
63
64#define __TIMER_INITIALIZER(_function, _flags) { \
65 .entry = { .next = TIMER_ENTRY_STATIC }, \
66 .function = (_function), \
67 .flags = (_flags), \
68 __TIMER_LOCKDEP_MAP_INITIALIZER( \
69 __FILE__ ":" __stringify(__LINE__)) \
70 }
71
72#define DEFINE_TIMER(_name, _function) \
73 struct timer_list _name = \
74 __TIMER_INITIALIZER(_function, 0)
75
76/*
77 * LOCKDEP and DEBUG timer interfaces.
78 */
79void init_timer_key(struct timer_list *timer,
80 void (*func)(struct timer_list *), unsigned int flags,
81 const char *name, struct lock_class_key *key);
82
83#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
84extern void init_timer_on_stack_key(struct timer_list *timer,
85 void (*func)(struct timer_list *),
86 unsigned int flags, const char *name,
87 struct lock_class_key *key);
88#else
89static inline void init_timer_on_stack_key(struct timer_list *timer,
90 void (*func)(struct timer_list *),
91 unsigned int flags,
92 const char *name,
93 struct lock_class_key *key)
94{
95 init_timer_key(timer, func, flags, name, key);
96}
97#endif
98
99#ifdef CONFIG_LOCKDEP
100#define __init_timer(_timer, _fn, _flags) \
101 do { \
102 static struct lock_class_key __key; \
103 init_timer_key((_timer), (_fn), (_flags), #_timer, &__key);\
104 } while (0)
105
106#define __init_timer_on_stack(_timer, _fn, _flags) \
107 do { \
108 static struct lock_class_key __key; \
109 init_timer_on_stack_key((_timer), (_fn), (_flags), \
110 #_timer, &__key); \
111 } while (0)
112#else
113#define __init_timer(_timer, _fn, _flags) \
114 init_timer_key((_timer), (_fn), (_flags), NULL, NULL)
115#define __init_timer_on_stack(_timer, _fn, _flags) \
116 init_timer_on_stack_key((_timer), (_fn), (_flags), NULL, NULL)
117#endif
118
119/**
120 * timer_setup - prepare a timer for first use
121 * @timer: the timer in question
122 * @callback: the function to call when timer expires
123 * @flags: any TIMER_* flags
124 *
125 * Regular timer initialization should use either DEFINE_TIMER() above,
126 * or timer_setup(). For timers on the stack, timer_setup_on_stack() must
127 * be used and must be balanced with a call to destroy_timer_on_stack().
128 */
129#define timer_setup(timer, callback, flags) \
130 __init_timer((timer), (callback), (flags))
131
132#define timer_setup_on_stack(timer, callback, flags) \
133 __init_timer_on_stack((timer), (callback), (flags))
134
135#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
136extern void destroy_timer_on_stack(struct timer_list *timer);
137#else
138static inline void destroy_timer_on_stack(struct timer_list *timer) { }
139#endif
140
141#define from_timer(var, callback_timer, timer_fieldname) \
142 container_of(callback_timer, typeof(*var), timer_fieldname)
143
144/**
145 * timer_pending - is a timer pending?
146 * @timer: the timer in question
147 *
148 * timer_pending will tell whether a given timer is currently pending,
149 * or not. Callers must ensure serialization wrt. other operations done
150 * to this timer, eg. interrupt contexts, or other CPUs on SMP.
151 *
152 * return value: 1 if the timer is pending, 0 if not.
153 */
154static inline int timer_pending(const struct timer_list * timer)
155{
156 return timer->entry.pprev != NULL;
157}
158
159extern void add_timer_on(struct timer_list *timer, int cpu);
160extern int del_timer(struct timer_list * timer);
161extern int mod_timer(struct timer_list *timer, unsigned long expires);
162extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
163extern int timer_reduce(struct timer_list *timer, unsigned long expires);
164
165/*
166 * The jiffies value which is added to now, when there is no timer
167 * in the timer wheel:
168 */
169#define NEXT_TIMER_MAX_DELTA ((1UL << 30) - 1)
170
171extern void add_timer(struct timer_list *timer);
172
173extern int try_to_del_timer_sync(struct timer_list *timer);
174
175#ifdef CONFIG_SMP
176 extern int del_timer_sync(struct timer_list *timer);
177#else
178# define del_timer_sync(t) del_timer(t)
179#endif
180
181#define del_singleshot_timer_sync(t) del_timer_sync(t)
182
183extern void init_timers(void);
184extern void run_local_timers(void);
185struct hrtimer;
186extern enum hrtimer_restart it_real_fn(struct hrtimer *);
187
188#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
189struct ctl_table;
190
191extern unsigned int sysctl_timer_migration;
192int timer_migration_handler(struct ctl_table *table, int write,
193 void __user *buffer, size_t *lenp,
194 loff_t *ppos);
195#endif
196
197unsigned long __round_jiffies(unsigned long j, int cpu);
198unsigned long __round_jiffies_relative(unsigned long j, int cpu);
199unsigned long round_jiffies(unsigned long j);
200unsigned long round_jiffies_relative(unsigned long j);
201
202unsigned long __round_jiffies_up(unsigned long j, int cpu);
203unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
204unsigned long round_jiffies_up(unsigned long j);
205unsigned long round_jiffies_up_relative(unsigned long j);
206
207#ifdef CONFIG_HOTPLUG_CPU
208int timers_prepare_cpu(unsigned int cpu);
209int timers_dead_cpu(unsigned int cpu);
210#else
211#define timers_prepare_cpu NULL
212#define timers_dead_cpu NULL
213#endif
214
215#endif