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
8 struct mm_struct;
9
10 __printf(4, 5)
11 struct 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
31 struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data),
32 void *data,
33 unsigned int cpu,
34 const char *namefmt);
35
36 void set_kthread_struct(struct task_struct *p);
37
38 void kthread_set_per_cpu(struct task_struct *k, int cpu);
39 bool kthread_is_per_cpu(struct task_struct *k);
40
41 /**
42 * kthread_run - create and wake a thread.
43 * @threadfn: the function to run until signal_pending(current).
44 * @data: data ptr for @threadfn.
45 * @namefmt: printf-style name for the thread.
46 *
47 * Description: Convenient wrapper for kthread_create() followed by
48 * wake_up_process(). Returns the kthread or ERR_PTR(-ENOMEM).
49 */
50 #define kthread_run(threadfn, data, namefmt, ...) \
51 ({ \
52 struct task_struct *__k \
53 = kthread_create(threadfn, data, namefmt, ## __VA_ARGS__); \
54 if (!IS_ERR(__k)) \
55 wake_up_process(__k); \
56 __k; \
57 })
58
59 /**
60 * kthread_run_on_cpu - create and wake a cpu bound thread.
61 * @threadfn: the function to run until signal_pending(current).
62 * @data: data ptr for @threadfn.
63 * @cpu: The cpu on which the thread should be bound,
64 * @namefmt: printf-style name for the thread. Format is restricted
65 * to "name.*%u". Code fills in cpu number.
66 *
67 * Description: Convenient wrapper for kthread_create_on_cpu()
68 * followed by wake_up_process(). Returns the kthread or
69 * ERR_PTR(-ENOMEM).
70 */
71 static inline struct task_struct *
kthread_run_on_cpu(int (* threadfn)(void * data),void * data,unsigned int cpu,const char * namefmt)72 kthread_run_on_cpu(int (*threadfn)(void *data), void *data,
73 unsigned int cpu, const char *namefmt)
74 {
75 struct task_struct *p;
76
77 p = kthread_create_on_cpu(threadfn, data, cpu, namefmt);
78 if (!IS_ERR(p))
79 wake_up_process(p);
80
81 return p;
82 }
83
84 void free_kthread_struct(struct task_struct *k);
85 void kthread_bind(struct task_struct *k, unsigned int cpu);
86 void kthread_bind_mask(struct task_struct *k, const struct cpumask *mask);
87 int kthread_stop(struct task_struct *k);
88 bool kthread_should_stop(void);
89 bool kthread_should_park(void);
90 bool __kthread_should_park(struct task_struct *k);
91 bool kthread_freezable_should_stop(bool *was_frozen);
92 void *kthread_func(struct task_struct *k);
93 void *kthread_data(struct task_struct *k);
94 void *kthread_probe_data(struct task_struct *k);
95 int kthread_park(struct task_struct *k);
96 void kthread_unpark(struct task_struct *k);
97 void kthread_parkme(void);
98
99 int kthreadd(void *unused);
100 extern struct task_struct *kthreadd_task;
101 extern int tsk_fork_get_node(struct task_struct *tsk);
102
103 /*
104 * Simple work processor based on kthread.
105 *
106 * This provides easier way to make use of kthreads. A kthread_work
107 * can be queued and flushed using queue/kthread_flush_work()
108 * respectively. Queued kthread_works are processed by a kthread
109 * running kthread_worker_fn().
110 */
111 struct kthread_work;
112 typedef void (*kthread_work_func_t)(struct kthread_work *work);
113 void kthread_delayed_work_timer_fn(struct timer_list *t);
114
115 enum {
116 KTW_FREEZABLE = 1 << 0, /* freeze during suspend */
117 };
118
119 struct kthread_worker {
120 unsigned int flags;
121 raw_spinlock_t lock;
122 struct list_head work_list;
123 struct list_head delayed_work_list;
124 struct task_struct *task;
125 struct kthread_work *current_work;
126 };
127
128 struct kthread_work {
129 struct list_head node;
130 kthread_work_func_t func;
131 struct kthread_worker *worker;
132 /* Number of canceling calls that are running at the moment. */
133 int canceling;
134 };
135
136 struct kthread_delayed_work {
137 struct kthread_work work;
138 struct timer_list timer;
139 };
140
141 #define KTHREAD_WORKER_INIT(worker) { \
142 .lock = __RAW_SPIN_LOCK_UNLOCKED((worker).lock), \
143 .work_list = LIST_HEAD_INIT((worker).work_list), \
144 .delayed_work_list = LIST_HEAD_INIT((worker).delayed_work_list),\
145 }
146
147 #define KTHREAD_WORK_INIT(work, fn) { \
148 .node = LIST_HEAD_INIT((work).node), \
149 .func = (fn), \
150 }
151
152 #define KTHREAD_DELAYED_WORK_INIT(dwork, fn) { \
153 .work = KTHREAD_WORK_INIT((dwork).work, (fn)), \
154 .timer = __TIMER_INITIALIZER(kthread_delayed_work_timer_fn,\
155 TIMER_IRQSAFE), \
156 }
157
158 #define DEFINE_KTHREAD_WORKER(worker) \
159 struct kthread_worker worker = KTHREAD_WORKER_INIT(worker)
160
161 #define DEFINE_KTHREAD_WORK(work, fn) \
162 struct kthread_work work = KTHREAD_WORK_INIT(work, fn)
163
164 #define DEFINE_KTHREAD_DELAYED_WORK(dwork, fn) \
165 struct kthread_delayed_work dwork = \
166 KTHREAD_DELAYED_WORK_INIT(dwork, fn)
167
168 /*
169 * kthread_worker.lock needs its own lockdep class key when defined on
170 * stack with lockdep enabled. Use the following macros in such cases.
171 */
172 #ifdef CONFIG_LOCKDEP
173 # define KTHREAD_WORKER_INIT_ONSTACK(worker) \
174 ({ kthread_init_worker(&worker); worker; })
175 # define DEFINE_KTHREAD_WORKER_ONSTACK(worker) \
176 struct kthread_worker worker = KTHREAD_WORKER_INIT_ONSTACK(worker)
177 #else
178 # define DEFINE_KTHREAD_WORKER_ONSTACK(worker) DEFINE_KTHREAD_WORKER(worker)
179 #endif
180
181 extern void __kthread_init_worker(struct kthread_worker *worker,
182 const char *name, struct lock_class_key *key);
183
184 #define kthread_init_worker(worker) \
185 do { \
186 static struct lock_class_key __key; \
187 __kthread_init_worker((worker), "("#worker")->lock", &__key); \
188 } while (0)
189
190 #define kthread_init_work(work, fn) \
191 do { \
192 memset((work), 0, sizeof(struct kthread_work)); \
193 INIT_LIST_HEAD(&(work)->node); \
194 (work)->func = (fn); \
195 } while (0)
196
197 #define kthread_init_delayed_work(dwork, fn) \
198 do { \
199 kthread_init_work(&(dwork)->work, (fn)); \
200 timer_setup(&(dwork)->timer, \
201 kthread_delayed_work_timer_fn, \
202 TIMER_IRQSAFE); \
203 } while (0)
204
205 int kthread_worker_fn(void *worker_ptr);
206
207 __printf(2, 3)
208 struct kthread_worker *
209 kthread_create_worker(unsigned int flags, const char namefmt[], ...);
210
211 __printf(3, 4) struct kthread_worker *
212 kthread_create_worker_on_cpu(int cpu, unsigned int flags,
213 const char namefmt[], ...);
214
215 bool kthread_queue_work(struct kthread_worker *worker,
216 struct kthread_work *work);
217
218 bool kthread_queue_delayed_work(struct kthread_worker *worker,
219 struct kthread_delayed_work *dwork,
220 unsigned long delay);
221
222 bool kthread_mod_delayed_work(struct kthread_worker *worker,
223 struct kthread_delayed_work *dwork,
224 unsigned long delay);
225
226 void kthread_flush_work(struct kthread_work *work);
227 void kthread_flush_worker(struct kthread_worker *worker);
228
229 bool kthread_cancel_work_sync(struct kthread_work *work);
230 bool kthread_cancel_delayed_work_sync(struct kthread_delayed_work *work);
231
232 void kthread_destroy_worker(struct kthread_worker *worker);
233
234 void kthread_use_mm(struct mm_struct *mm);
235 void kthread_unuse_mm(struct mm_struct *mm);
236
237 struct cgroup_subsys_state;
238
239 #ifdef CONFIG_BLK_CGROUP
240 void kthread_associate_blkcg(struct cgroup_subsys_state *css);
241 struct cgroup_subsys_state *kthread_blkcg(void);
242 #else
kthread_associate_blkcg(struct cgroup_subsys_state * css)243 static inline void kthread_associate_blkcg(struct cgroup_subsys_state *css) { }
kthread_blkcg(void)244 static inline struct cgroup_subsys_state *kthread_blkcg(void)
245 {
246 return NULL;
247 }
248 #endif
249 #endif /* _LINUX_KTHREAD_H */
250