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