projects/linux·blob v6.4-rc7 · refs

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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
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 * @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 */
91void 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
96extern 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
101static 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 init_timer_key(timer, func, flags, name, key);
108}
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
148extern void destroy_timer_on_stack(struct timer_list *timer);
149#else
150static 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 */
166static inline int timer_pending(const struct timer_list * timer)
167{
168 return !hlist_unhashed_lockless(&timer->entry);
169}
170
171extern void add_timer_on(struct timer_list *timer, int cpu);
172extern int mod_timer(struct timer_list *timer, unsigned long expires);
173extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
174extern 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
182extern void add_timer(struct timer_list *timer);
183
184extern int try_to_del_timer_sync(struct timer_list *timer);
185extern int timer_delete_sync(struct timer_list *timer);
186extern int timer_delete(struct timer_list *timer);
187extern int timer_shutdown_sync(struct timer_list *timer);
188extern int timer_shutdown(struct timer_list *timer);
189
190/**
191 * del_timer_sync - Delete a pending timer and wait for a running callback
192 * @timer: The timer to be deleted
193 *
194 * See timer_delete_sync() for detailed explanation.
195 *
196 * Do not use in new code. Use timer_delete_sync() instead.
197 */
198static inline int del_timer_sync(struct timer_list *timer)
199{
200 return timer_delete_sync(timer);
201}
202
203/**
204 * del_timer - Delete a pending timer
205 * @timer: The timer to be deleted
206 *
207 * See timer_delete() for detailed explanation.
208 *
209 * Do not use in new code. Use timer_delete() instead.
210 */
211static inline int del_timer(struct timer_list *timer)
212{
213 return timer_delete(timer);
214}
215
216extern void init_timers(void);
217struct hrtimer;
218extern enum hrtimer_restart it_real_fn(struct hrtimer *);
219
220unsigned long __round_jiffies(unsigned long j, int cpu);
221unsigned long __round_jiffies_relative(unsigned long j, int cpu);
222unsigned long round_jiffies(unsigned long j);
223unsigned long round_jiffies_relative(unsigned long j);
224
225unsigned long __round_jiffies_up(unsigned long j, int cpu);
226unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
227unsigned long round_jiffies_up(unsigned long j);
228unsigned long round_jiffies_up_relative(unsigned long j);
229
230#ifdef CONFIG_HOTPLUG_CPU
231int timers_prepare_cpu(unsigned int cpu);
232int timers_dead_cpu(unsigned int cpu);
233#else
234#define timers_prepare_cpu NULL
235#define timers_dead_cpu NULL
236#endif
237
238#endif