1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_KTHREAD_H
3#define _LINUX_KTHREAD_H
4/* Simple interface for creating and stopping kernel threads without mess. */
5#include <linux/err.h>
6#include <linux/sched.h>
7
8struct mm_struct;
9
10__printf(4, 5)
11struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
12 void *data,
13 int node,
14 const char namefmt[], ...);
15
16/**
17 * kthread_create - create a kthread on the current node
18 * @threadfn: the function to run in the thread
19 * @data: data pointer for @threadfn()
20 * @namefmt: printf-style format string for the thread name
21 * @arg: arguments for @namefmt.
22 *
23 * This macro will create a kthread on the current node, leaving it in
24 * the stopped state. This is just a helper for kthread_create_on_node();
25 * see the documentation there for more details.
26 */
27#define kthread_create(threadfn, data, namefmt, arg...) \
28 kthread_create_on_node(threadfn, data, NUMA_NO_NODE, namefmt, ##arg)
29
30
31struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data),
32 void *data,
33 unsigned int cpu,
34 const char *namefmt);
35
36void get_kthread_comm(char *buf, size_t buf_size, struct task_struct *tsk);
37bool set_kthread_struct(struct task_struct *p);
38
39void kthread_set_per_cpu(struct task_struct *k, int cpu);
40bool kthread_is_per_cpu(struct task_struct *k);
41
42/**
43 * kthread_run - create and wake a thread.
44 * @threadfn: the function to run until signal_pending(current).
45 * @data: data ptr for @threadfn.
46 * @namefmt: printf-style name for the thread.
47 *
48 * Description: Convenient wrapper for kthread_create() followed by
49 * wake_up_process(). Returns the kthread or ERR_PTR(-ENOMEM).
50 */
51#define kthread_run(threadfn, data, namefmt, ...) \
52({ \
53 struct task_struct *__k \
54 = kthread_create(threadfn, data, namefmt, ## __VA_ARGS__); \
55 if (!IS_ERR(__k)) \
56 wake_up_process(__k); \
57 __k; \
58})
59
60/**
61 * kthread_run_on_cpu - create and wake a cpu bound thread.
62 * @threadfn: the function to run until signal_pending(current).
63 * @data: data ptr for @threadfn.
64 * @cpu: The cpu on which the thread should be bound,
65 * @namefmt: printf-style name for the thread. Format is restricted
66 * to "name.*%u". Code fills in cpu number.
67 *
68 * Description: Convenient wrapper for kthread_create_on_cpu()
69 * followed by wake_up_process(). Returns the kthread or
70 * ERR_PTR(-ENOMEM).
71 */
72static inline struct task_struct *
73kthread_run_on_cpu(int (*threadfn)(void *data), void *data,
74 unsigned int cpu, const char *namefmt)
75{
76 struct task_struct *p;
77
78 p = kthread_create_on_cpu(threadfn, data, cpu, namefmt);
79 if (!IS_ERR(ptr: p))
80 wake_up_process(tsk: p);
81
82 return p;
83}
84
85void free_kthread_struct(struct task_struct *k);
86void kthread_bind(struct task_struct *k, unsigned int cpu);
87void kthread_bind_mask(struct task_struct *k, const struct cpumask *mask);
88int kthread_affine_preferred(struct task_struct *p, const struct cpumask *mask);
89int kthread_stop(struct task_struct *k);
90int kthread_stop_put(struct task_struct *k);
91bool kthread_should_stop(void);
92bool kthread_should_park(void);
93bool kthread_should_stop_or_park(void);
94bool kthread_freezable_should_stop(bool *was_frozen);
95void *kthread_func(struct task_struct *k);
96void *kthread_data(struct task_struct *k);
97void *kthread_probe_data(struct task_struct *k);
98int kthread_park(struct task_struct *k);
99void kthread_unpark(struct task_struct *k);
100void kthread_parkme(void);
101void kthread_exit(long result) __noreturn;
102void kthread_complete_and_exit(struct completion *, long) __noreturn;
103
104int kthreadd(void *unused);
105extern struct task_struct *kthreadd_task;
106extern int tsk_fork_get_node(struct task_struct *tsk);
107
108/*
109 * Simple work processor based on kthread.
110 *
111 * This provides easier way to make use of kthreads. A kthread_work
112 * can be queued and flushed using queue/kthread_flush_work()
113 * respectively. Queued kthread_works are processed by a kthread
114 * running kthread_worker_fn().
115 */
116struct kthread_work;
117typedef void (*kthread_work_func_t)(struct kthread_work *work);
118void kthread_delayed_work_timer_fn(struct timer_list *t);
119
120enum {
121 KTW_FREEZABLE = 1 << 0, /* freeze during suspend */
122};
123
124struct kthread_worker {
125 unsigned int flags;
126 raw_spinlock_t lock;
127 struct list_head work_list;
128 struct list_head delayed_work_list;
129 struct task_struct *task;
130 struct kthread_work *current_work;
131};
132
133struct kthread_work {
134 struct list_head node;
135 kthread_work_func_t func;
136 struct kthread_worker *worker;
137 /* Number of canceling calls that are running at the moment. */
138 int canceling;
139};
140
141struct kthread_delayed_work {
142 struct kthread_work work;
143 struct timer_list timer;
144};
145
146#define KTHREAD_WORK_INIT(work, fn) { \
147 .node = LIST_HEAD_INIT((work).node), \
148 .func = (fn), \
149 }
150
151#define KTHREAD_DELAYED_WORK_INIT(dwork, fn) { \
152 .work = KTHREAD_WORK_INIT((dwork).work, (fn)), \
153 .timer = __TIMER_INITIALIZER(kthread_delayed_work_timer_fn,\
154 TIMER_IRQSAFE), \
155 }
156
157#define DEFINE_KTHREAD_WORK(work, fn) \
158 struct kthread_work work = KTHREAD_WORK_INIT(work, fn)
159
160#define DEFINE_KTHREAD_DELAYED_WORK(dwork, fn) \
161 struct kthread_delayed_work dwork = \
162 KTHREAD_DELAYED_WORK_INIT(dwork, fn)
163
164extern void __kthread_init_worker(struct kthread_worker *worker,
165 const char *name, struct lock_class_key *key);
166
167#define kthread_init_worker(worker) \
168 do { \
169 static struct lock_class_key __key; \
170 __kthread_init_worker((worker), "("#worker")->lock", &__key); \
171 } while (0)
172
173#define kthread_init_work(work, fn) \
174 do { \
175 memset((work), 0, sizeof(struct kthread_work)); \
176 INIT_LIST_HEAD(&(work)->node); \
177 (work)->func = (fn); \
178 } while (0)
179
180#define kthread_init_delayed_work(dwork, fn) \
181 do { \
182 kthread_init_work(&(dwork)->work, (fn)); \
183 timer_setup(&(dwork)->timer, \
184 kthread_delayed_work_timer_fn, \
185 TIMER_IRQSAFE); \
186 } while (0)
187
188int kthread_worker_fn(void *worker_ptr);
189
190__printf(3, 4)
191struct kthread_worker *kthread_create_worker_on_node(unsigned int flags,
192 int node,
193 const char namefmt[], ...);
194
195#define kthread_create_worker(flags, namefmt, ...) \
196 kthread_create_worker_on_node(flags, NUMA_NO_NODE, namefmt, ## __VA_ARGS__);
197
198/**
199 * kthread_run_worker - create and wake a kthread worker.
200 * @flags: flags modifying the default behavior of the worker
201 * @namefmt: printf-style name for the thread.
202 *
203 * Description: Convenient wrapper for kthread_create_worker() followed by
204 * wake_up_process(). Returns the kthread_worker or ERR_PTR(-ENOMEM).
205 */
206#define kthread_run_worker(flags, namefmt, ...) \
207({ \
208 struct kthread_worker *__kw \
209 = kthread_create_worker(flags, namefmt, ## __VA_ARGS__); \
210 if (!IS_ERR(__kw)) \
211 wake_up_process(__kw->task); \
212 __kw; \
213})
214
215struct kthread_worker *
216kthread_create_worker_on_cpu(int cpu, unsigned int flags,
217 const char namefmt[]);
218
219/**
220 * kthread_run_worker_on_cpu - create and wake a cpu bound kthread worker.
221 * @cpu: CPU number
222 * @flags: flags modifying the default behavior of the worker
223 * @namefmt: printf-style name for the thread. Format is restricted
224 * to "name.*%u". Code fills in cpu number.
225 *
226 * Description: Convenient wrapper for kthread_create_worker_on_cpu()
227 * followed by wake_up_process(). Returns the kthread_worker or
228 * ERR_PTR(-ENOMEM).
229 */
230static inline struct kthread_worker *
231kthread_run_worker_on_cpu(int cpu, unsigned int flags,
232 const char namefmt[])
233{
234 struct kthread_worker *kw;
235
236 kw = kthread_create_worker_on_cpu(cpu, flags, namefmt);
237 if (!IS_ERR(ptr: kw))
238 wake_up_process(tsk: kw->task);
239
240 return kw;
241}
242
243bool kthread_queue_work(struct kthread_worker *worker,
244 struct kthread_work *work);
245
246bool kthread_queue_delayed_work(struct kthread_worker *worker,
247 struct kthread_delayed_work *dwork,
248 unsigned long delay);
249
250bool kthread_mod_delayed_work(struct kthread_worker *worker,
251 struct kthread_delayed_work *dwork,
252 unsigned long delay);
253
254void kthread_flush_work(struct kthread_work *work);
255void kthread_flush_worker(struct kthread_worker *worker);
256
257bool kthread_cancel_work_sync(struct kthread_work *work);
258bool kthread_cancel_delayed_work_sync(struct kthread_delayed_work *work);
259
260void kthread_destroy_worker(struct kthread_worker *worker);
261
262void kthread_use_mm(struct mm_struct *mm);
263void kthread_unuse_mm(struct mm_struct *mm);
264
265struct cgroup_subsys_state;
266
267#ifdef CONFIG_BLK_CGROUP
268void kthread_associate_blkcg(struct cgroup_subsys_state *css);
269struct cgroup_subsys_state *kthread_blkcg(void);
270#else
271static inline void kthread_associate_blkcg(struct cgroup_subsys_state *css) { }
272#endif
273#endif /* _LINUX_KTHREAD_H */
274