xref: /linux-6.15/include/linux/timer.h (revision 1da177e4)
1 #ifndef _LINUX_TIMER_H
2 #define _LINUX_TIMER_H
3 
4 #include <linux/config.h>
5 #include <linux/list.h>
6 #include <linux/spinlock.h>
7 #include <linux/stddef.h>
8 
9 struct tvec_t_base_s;
10 
11 struct timer_list {
12 	struct list_head entry;
13 	unsigned long expires;
14 
15 	spinlock_t lock;
16 	unsigned long magic;
17 
18 	void (*function)(unsigned long);
19 	unsigned long data;
20 
21 	struct tvec_t_base_s *base;
22 };
23 
24 #define TIMER_MAGIC	0x4b87ad6e
25 
26 #define TIMER_INITIALIZER(_function, _expires, _data) {		\
27 		.function = (_function),			\
28 		.expires = (_expires),				\
29 		.data = (_data),				\
30 		.base = NULL,					\
31 		.magic = TIMER_MAGIC,				\
32 		.lock = SPIN_LOCK_UNLOCKED,			\
33 	}
34 
35 /***
36  * init_timer - initialize a timer.
37  * @timer: the timer to be initialized
38  *
39  * init_timer() must be done to a timer prior calling *any* of the
40  * other timer functions.
41  */
42 static inline void init_timer(struct timer_list * timer)
43 {
44 	timer->base = NULL;
45 	timer->magic = TIMER_MAGIC;
46 	spin_lock_init(&timer->lock);
47 }
48 
49 /***
50  * timer_pending - is a timer pending?
51  * @timer: the timer in question
52  *
53  * timer_pending will tell whether a given timer is currently pending,
54  * or not. Callers must ensure serialization wrt. other operations done
55  * to this timer, eg. interrupt contexts, or other CPUs on SMP.
56  *
57  * return value: 1 if the timer is pending, 0 if not.
58  */
59 static inline int timer_pending(const struct timer_list * timer)
60 {
61 	return timer->base != NULL;
62 }
63 
64 extern void add_timer_on(struct timer_list *timer, int cpu);
65 extern int del_timer(struct timer_list * timer);
66 extern int __mod_timer(struct timer_list *timer, unsigned long expires);
67 extern int mod_timer(struct timer_list *timer, unsigned long expires);
68 
69 extern unsigned long next_timer_interrupt(void);
70 
71 /***
72  * add_timer - start a timer
73  * @timer: the timer to be added
74  *
75  * The kernel will do a ->function(->data) callback from the
76  * timer interrupt at the ->expired point in the future. The
77  * current time is 'jiffies'.
78  *
79  * The timer's ->expired, ->function (and if the handler uses it, ->data)
80  * fields must be set prior calling this function.
81  *
82  * Timers with an ->expired field in the past will be executed in the next
83  * timer tick.
84  */
85 static inline void add_timer(struct timer_list * timer)
86 {
87 	__mod_timer(timer, timer->expires);
88 }
89 
90 #ifdef CONFIG_SMP
91   extern int del_timer_sync(struct timer_list *timer);
92   extern int del_singleshot_timer_sync(struct timer_list *timer);
93 #else
94 # define del_timer_sync(t) del_timer(t)
95 # define del_singleshot_timer_sync(t) del_timer(t)
96 #endif
97 
98 extern void init_timers(void);
99 extern void run_local_timers(void);
100 extern void it_real_fn(unsigned long);
101 
102 #endif
103