xref: /linux-6.15/include/linux/timer.h (revision d289bf7b)
1 #ifndef _LINUX_TIMER_H
2 #define _LINUX_TIMER_H
3 
4 #include <linux/list.h>
5 #include <linux/ktime.h>
6 #include <linux/stddef.h>
7 
8 struct tvec_base;
9 
10 struct timer_list {
11 	struct list_head entry;
12 	unsigned long expires;
13 
14 	void (*function)(unsigned long);
15 	unsigned long data;
16 
17 	struct tvec_base *base;
18 #ifdef CONFIG_TIMER_STATS
19 	void *start_site;
20 	char start_comm[16];
21 	int start_pid;
22 #endif
23 };
24 
25 extern struct tvec_base boot_tvec_bases;
26 
27 #define TIMER_INITIALIZER(_function, _expires, _data) {		\
28 		.function = (_function),			\
29 		.expires = (_expires),				\
30 		.data = (_data),				\
31 		.base = &boot_tvec_bases,			\
32 	}
33 
34 #define DEFINE_TIMER(_name, _function, _expires, _data)		\
35 	struct timer_list _name =				\
36 		TIMER_INITIALIZER(_function, _expires, _data)
37 
38 void init_timer(struct timer_list *timer);
39 void init_timer_deferrable(struct timer_list *timer);
40 
41 static inline void setup_timer(struct timer_list * timer,
42 				void (*function)(unsigned long),
43 				unsigned long data)
44 {
45 	timer->function = function;
46 	timer->data = data;
47 	init_timer(timer);
48 }
49 
50 /**
51  * timer_pending - is a timer pending?
52  * @timer: the timer in question
53  *
54  * timer_pending will tell whether a given timer is currently pending,
55  * or not. Callers must ensure serialization wrt. other operations done
56  * to this timer, eg. interrupt contexts, or other CPUs on SMP.
57  *
58  * return value: 1 if the timer is pending, 0 if not.
59  */
60 static inline int timer_pending(const struct timer_list * timer)
61 {
62 	return timer->entry.next != NULL;
63 }
64 
65 extern void add_timer_on(struct timer_list *timer, int cpu);
66 extern int del_timer(struct timer_list * timer);
67 extern int __mod_timer(struct timer_list *timer, unsigned long expires);
68 extern int mod_timer(struct timer_list *timer, unsigned long expires);
69 
70 /*
71  * The jiffies value which is added to now, when there is no timer
72  * in the timer wheel:
73  */
74 #define NEXT_TIMER_MAX_DELTA	((1UL << 30) - 1)
75 
76 /*
77  * Return when the next timer-wheel timeout occurs (in absolute jiffies),
78  * locks the timer base:
79  */
80 extern unsigned long next_timer_interrupt(void);
81 /*
82  * Return when the next timer-wheel timeout occurs (in absolute jiffies),
83  * locks the timer base and does the comparison against the given
84  * jiffie.
85  */
86 extern unsigned long get_next_timer_interrupt(unsigned long now);
87 
88 /*
89  * Timer-statistics info:
90  */
91 #ifdef CONFIG_TIMER_STATS
92 
93 #define TIMER_STATS_FLAG_DEFERRABLE	0x1
94 
95 extern void init_timer_stats(void);
96 
97 extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
98 				     void *timerf, char *comm,
99 				     unsigned int timer_flag);
100 
101 extern void __timer_stats_timer_set_start_info(struct timer_list *timer,
102 					       void *addr);
103 
104 static inline void timer_stats_timer_set_start_info(struct timer_list *timer)
105 {
106 	__timer_stats_timer_set_start_info(timer, __builtin_return_address(0));
107 }
108 
109 static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
110 {
111 	timer->start_site = NULL;
112 }
113 #else
114 static inline void init_timer_stats(void)
115 {
116 }
117 
118 static inline void timer_stats_timer_set_start_info(struct timer_list *timer)
119 {
120 }
121 
122 static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
123 {
124 }
125 #endif
126 
127 /**
128  * add_timer - start a timer
129  * @timer: the timer to be added
130  *
131  * The kernel will do a ->function(->data) callback from the
132  * timer interrupt at the ->expires point in the future. The
133  * current time is 'jiffies'.
134  *
135  * The timer's ->expires, ->function (and if the handler uses it, ->data)
136  * fields must be set prior calling this function.
137  *
138  * Timers with an ->expires field in the past will be executed in the next
139  * timer tick.
140  */
141 static inline void add_timer(struct timer_list *timer)
142 {
143 	BUG_ON(timer_pending(timer));
144 	__mod_timer(timer, timer->expires);
145 }
146 
147 #ifdef CONFIG_SMP
148   extern int try_to_del_timer_sync(struct timer_list *timer);
149   extern int del_timer_sync(struct timer_list *timer);
150 #else
151 # define try_to_del_timer_sync(t)	del_timer(t)
152 # define del_timer_sync(t)		del_timer(t)
153 #endif
154 
155 #define del_singleshot_timer_sync(t) del_timer_sync(t)
156 
157 extern void init_timers(void);
158 extern void run_local_timers(void);
159 struct hrtimer;
160 extern enum hrtimer_restart it_real_fn(struct hrtimer *);
161 
162 unsigned long __round_jiffies(unsigned long j, int cpu);
163 unsigned long __round_jiffies_relative(unsigned long j, int cpu);
164 unsigned long round_jiffies(unsigned long j);
165 unsigned long round_jiffies_relative(unsigned long j);
166 
167 
168 #endif
169