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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 : :
11 : : struct 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_ARRAYSHIFT 22
71 : : #define TIMER_ARRAYMASK 0xFFC00000
72 : :
73 : : #define TIMER_TRACE_FLAGMASK (TIMER_MIGRATING | TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
74 : :
75 : : #define __TIMER_INITIALIZER(_function, _flags) { \
76 : : .entry = { .next = TIMER_ENTRY_STATIC }, \
77 : : .function = (_function), \
78 : : .flags = (_flags), \
79 : : __TIMER_LOCKDEP_MAP_INITIALIZER( \
80 : : __FILE__ ":" __stringify(__LINE__)) \
81 : : }
82 : :
83 : : #define DEFINE_TIMER(_name, _function) \
84 : : struct timer_list _name = \
85 : : __TIMER_INITIALIZER(_function, 0)
86 : :
87 : : /*
88 : : * LOCKDEP and DEBUG timer interfaces.
89 : : */
90 : : void init_timer_key(struct timer_list *timer,
91 : : void (*func)(struct timer_list *), unsigned int flags,
92 : : const char *name, struct lock_class_key *key);
93 : :
94 : : #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
95 : : extern void init_timer_on_stack_key(struct timer_list *timer,
96 : : void (*func)(struct timer_list *),
97 : : unsigned int flags, const char *name,
98 : : struct lock_class_key *key);
99 : : #else
100 : : static inline void init_timer_on_stack_key(struct timer_list *timer,
101 : : void (*func)(struct timer_list *),
102 : : unsigned int flags,
103 : : const char *name,
104 : : struct lock_class_key *key)
105 : : {
106 : 0 : init_timer_key(timer, func, flags, name, key);
107 : : }
108 : : #endif
109 : :
110 : : #ifdef CONFIG_LOCKDEP
111 : : #define __init_timer(_timer, _fn, _flags) \
112 : : do { \
113 : : static struct lock_class_key __key; \
114 : : init_timer_key((_timer), (_fn), (_flags), #_timer, &__key);\
115 : : } while (0)
116 : :
117 : : #define __init_timer_on_stack(_timer, _fn, _flags) \
118 : : do { \
119 : : static struct lock_class_key __key; \
120 : : init_timer_on_stack_key((_timer), (_fn), (_flags), \
121 : : #_timer, &__key); \
122 : : } while (0)
123 : : #else
124 : : #define __init_timer(_timer, _fn, _flags) \
125 : : init_timer_key((_timer), (_fn), (_flags), NULL, NULL)
126 : : #define __init_timer_on_stack(_timer, _fn, _flags) \
127 : : init_timer_on_stack_key((_timer), (_fn), (_flags), NULL, NULL)
128 : : #endif
129 : :
130 : : /**
131 : : * timer_setup - prepare a timer for first use
132 : : * @timer: the timer in question
133 : : * @callback: the function to call when timer expires
134 : : * @flags: any TIMER_* flags
135 : : *
136 : : * Regular timer initialization should use either DEFINE_TIMER() above,
137 : : * or timer_setup(). For timers on the stack, timer_setup_on_stack() must
138 : : * be used and must be balanced with a call to destroy_timer_on_stack().
139 : : */
140 : : #define timer_setup(timer, callback, flags) \
141 : : __init_timer((timer), (callback), (flags))
142 : :
143 : : #define timer_setup_on_stack(timer, callback, flags) \
144 : : __init_timer_on_stack((timer), (callback), (flags))
145 : :
146 : : #ifdef CONFIG_DEBUG_OBJECTS_TIMERS
147 : : extern void destroy_timer_on_stack(struct timer_list *timer);
148 : : #else
149 : : static inline void destroy_timer_on_stack(struct timer_list *timer) { }
150 : : #endif
151 : :
152 : : #define from_timer(var, callback_timer, timer_fieldname) \
153 : : container_of(callback_timer, typeof(*var), timer_fieldname)
154 : :
155 : : /**
156 : : * timer_pending - is a timer pending?
157 : : * @timer: the timer in question
158 : : *
159 : : * timer_pending will tell whether a given timer is currently pending,
160 : : * or not. Callers must ensure serialization wrt. other operations done
161 : : * to this timer, eg. interrupt contexts, or other CPUs on SMP.
162 : : *
163 : : * return value: 1 if the timer is pending, 0 if not.
164 : : */
165 : : static inline int timer_pending(const struct timer_list * timer)
166 : : {
167 : 36540098 : return timer->entry.pprev != NULL;
168 : : }
169 : :
170 : : extern void add_timer_on(struct timer_list *timer, int cpu);
171 : : extern int del_timer(struct timer_list * timer);
172 : : extern int mod_timer(struct timer_list *timer, unsigned long expires);
173 : : extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
174 : : extern 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 : :
182 : : extern void add_timer(struct timer_list *timer);
183 : :
184 : : extern int try_to_del_timer_sync(struct timer_list *timer);
185 : :
186 : : #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
187 : : extern int del_timer_sync(struct timer_list *timer);
188 : : #else
189 : : # define del_timer_sync(t) del_timer(t)
190 : : #endif
191 : :
192 : : #define del_singleshot_timer_sync(t) del_timer_sync(t)
193 : :
194 : : extern void init_timers(void);
195 : : extern void run_local_timers(void);
196 : : struct hrtimer;
197 : : extern enum hrtimer_restart it_real_fn(struct hrtimer *);
198 : :
199 : : #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
200 : : struct ctl_table;
201 : :
202 : : extern unsigned int sysctl_timer_migration;
203 : : int timer_migration_handler(struct ctl_table *table, int write,
204 : : void __user *buffer, size_t *lenp,
205 : : loff_t *ppos);
206 : : #endif
207 : :
208 : : unsigned long __round_jiffies(unsigned long j, int cpu);
209 : : unsigned long __round_jiffies_relative(unsigned long j, int cpu);
210 : : unsigned long round_jiffies(unsigned long j);
211 : : unsigned long round_jiffies_relative(unsigned long j);
212 : :
213 : : unsigned long __round_jiffies_up(unsigned long j, int cpu);
214 : : unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
215 : : unsigned long round_jiffies_up(unsigned long j);
216 : : unsigned long round_jiffies_up_relative(unsigned long j);
217 : :
218 : : #ifdef CONFIG_HOTPLUG_CPU
219 : : int timers_prepare_cpu(unsigned int cpu);
220 : : int timers_dead_cpu(unsigned int cpu);
221 : : #else
222 : : #define timers_prepare_cpu NULL
223 : : #define timers_dead_cpu NULL
224 : : #endif
225 : :
226 : : #endif
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