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 get_kthread_comm(char *buf, size_t buf_size, struct task_struct *tsk);
37 void set_kthread_struct(struct task_struct *p);
38
39 void kthread_set_per_cpu(struct task_struct *k, int cpu);
40 bool 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 */
72 static inline struct task_struct *
kthread_run_on_cpu(int (* threadfn)(void * data),void * data,unsigned int cpu,const char * namefmt)73 kthread_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(p))
80 wake_up_process(p);
81
82 return p;
83 }
84
85 void free_kthread_struct(struct task_struct *k);
86 void kthread_bind(struct task_struct *k, unsigned int cpu);
87 void kthread_bind_mask(struct task_struct *k, const struct cpumask *mask);
88 int kthread_stop(struct task_struct *k);
89 bool kthread_should_stop(void);
90 bool kthread_should_park(void);
91 bool __kthread_should_park(struct task_struct *k);
92 bool kthread_freezable_should_stop(bool *was_frozen);
93 void *kthread_func(struct task_struct *k);
94 void *kthread_data(struct task_struct *k);
95 void *kthread_probe_data(struct task_struct *k);
96 int kthread_park(struct task_struct *k);
97 void kthread_unpark(struct task_struct *k);
98 void kthread_parkme(void);
99
100 int kthreadd(void *unused);
101 extern struct task_struct *kthreadd_task;
102 extern int tsk_fork_get_node(struct task_struct *tsk);
103
104 /*
105 * Simple work processor based on kthread.
106 *
107 * This provides easier way to make use of kthreads. A kthread_work
108 * can be queued and flushed using queue/kthread_flush_work()
109 * respectively. Queued kthread_works are processed by a kthread
110 * running kthread_worker_fn().
111 */
112 struct kthread_work;
113 typedef void (*kthread_work_func_t)(struct kthread_work *work);
114 void kthread_delayed_work_timer_fn(struct timer_list *t);
115
116 enum {
117 KTW_FREEZABLE = 1 << 0, /* freeze during suspend */
118 };
119
120 struct kthread_worker {
121 unsigned int flags;
122 raw_spinlock_t lock;
123 struct list_head work_list;
124 struct list_head delayed_work_list;
125 struct task_struct *task;
126 struct kthread_work *current_work;
127 };
128
129 struct kthread_work {
130 struct list_head node;
131 kthread_work_func_t func;
132 struct kthread_worker *worker;
133 /* Number of canceling calls that are running at the moment. */
134 int canceling;
135 };
136
137 struct kthread_delayed_work {
138 struct kthread_work work;
139 struct timer_list timer;
140 };
141
142 #define KTHREAD_WORKER_INIT(worker) { \
143 .lock = __RAW_SPIN_LOCK_UNLOCKED((worker).lock), \
144 .work_list = LIST_HEAD_INIT((worker).work_list), \
145 .delayed_work_list = LIST_HEAD_INIT((worker).delayed_work_list),\
146 }
147
148 #define KTHREAD_WORK_INIT(work, fn) { \
149 .node = LIST_HEAD_INIT((work).node), \
150 .func = (fn), \
151 }
152
153 #define KTHREAD_DELAYED_WORK_INIT(dwork, fn) { \
154 .work = KTHREAD_WORK_INIT((dwork).work, (fn)), \
155 .timer = __TIMER_INITIALIZER(kthread_delayed_work_timer_fn,\
156 TIMER_IRQSAFE), \
157 }
158
159 #define DEFINE_KTHREAD_WORKER(worker) \
160 struct kthread_worker worker = KTHREAD_WORKER_INIT(worker)
161
162 #define DEFINE_KTHREAD_WORK(work, fn) \
163 struct kthread_work work = KTHREAD_WORK_INIT(work, fn)
164
165 #define DEFINE_KTHREAD_DELAYED_WORK(dwork, fn) \
166 struct kthread_delayed_work dwork = \
167 KTHREAD_DELAYED_WORK_INIT(dwork, fn)
168
169 /*
170 * kthread_worker.lock needs its own lockdep class key when defined on
171 * stack with lockdep enabled. Use the following macros in such cases.
172 */
173 #ifdef CONFIG_LOCKDEP
174 # define KTHREAD_WORKER_INIT_ONSTACK(worker) \
175 ({ kthread_init_worker(&worker); worker; })
176 # define DEFINE_KTHREAD_WORKER_ONSTACK(worker) \
177 struct kthread_worker worker = KTHREAD_WORKER_INIT_ONSTACK(worker)
178 #else
179 # define DEFINE_KTHREAD_WORKER_ONSTACK(worker) DEFINE_KTHREAD_WORKER(worker)
180 #endif
181
182 extern void __kthread_init_worker(struct kthread_worker *worker,
183 const char *name, struct lock_class_key *key);
184
185 #define kthread_init_worker(worker) \
186 do { \
187 static struct lock_class_key __key; \
188 __kthread_init_worker((worker), "("#worker")->lock", &__key); \
189 } while (0)
190
191 #define kthread_init_work(work, fn) \
192 do { \
193 memset((work), 0, sizeof(struct kthread_work)); \
194 INIT_LIST_HEAD(&(work)->node); \
195 (work)->func = (fn); \
196 } while (0)
197
198 #define kthread_init_delayed_work(dwork, fn) \
199 do { \
200 kthread_init_work(&(dwork)->work, (fn)); \
201 timer_setup(&(dwork)->timer, \
202 kthread_delayed_work_timer_fn, \
203 TIMER_IRQSAFE); \
204 } while (0)
205
206 int kthread_worker_fn(void *worker_ptr);
207
208 __printf(2, 3)
209 struct kthread_worker *
210 kthread_create_worker(unsigned int flags, const char namefmt[], ...);
211
212 __printf(3, 4) struct kthread_worker *
213 kthread_create_worker_on_cpu(int cpu, unsigned int flags,
214 const char namefmt[], ...);
215
216 bool kthread_queue_work(struct kthread_worker *worker,
217 struct kthread_work *work);
218
219 bool kthread_queue_delayed_work(struct kthread_worker *worker,
220 struct kthread_delayed_work *dwork,
221 unsigned long delay);
222
223 bool kthread_mod_delayed_work(struct kthread_worker *worker,
224 struct kthread_delayed_work *dwork,
225 unsigned long delay);
226
227 void kthread_flush_work(struct kthread_work *work);
228 void kthread_flush_worker(struct kthread_worker *worker);
229
230 bool kthread_cancel_work_sync(struct kthread_work *work);
231 bool kthread_cancel_delayed_work_sync(struct kthread_delayed_work *work);
232
233 void kthread_destroy_worker(struct kthread_worker *worker);
234
235 void kthread_use_mm(struct mm_struct *mm);
236 void kthread_unuse_mm(struct mm_struct *mm);
237
238 struct cgroup_subsys_state;
239
240 #ifdef CONFIG_BLK_CGROUP
241 void kthread_associate_blkcg(struct cgroup_subsys_state *css);
242 struct cgroup_subsys_state *kthread_blkcg(void);
243 #else
kthread_associate_blkcg(struct cgroup_subsys_state * css)244 static inline void kthread_associate_blkcg(struct cgroup_subsys_state *css) { }
kthread_blkcg(void)245 static inline struct cgroup_subsys_state *kthread_blkcg(void)
246 {
247 return NULL;
248 }
249 #endif
250 #endif /* _LINUX_KTHREAD_H */
251