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 __printf(4, 5)
9 struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
10 void *data,
11 int node,
12 const char namefmt[], ...);
13
14 /**
15 * kthread_create - create a kthread on the current node
16 * @threadfn: the function to run in the thread
17 * @data: data pointer for @threadfn()
18 * @namefmt: printf-style format string for the thread name
19 * @arg...: arguments for @namefmt.
20 *
21 * This macro will create a kthread on the current node, leaving it in
22 * the stopped state. This is just a helper for kthread_create_on_node();
23 * see the documentation there for more details.
24 */
25 #define kthread_create(threadfn, data, namefmt, arg...) \
26 kthread_create_on_node(threadfn, data, NUMA_NO_NODE, namefmt, ##arg)
27
28
29 struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data),
30 void *data,
31 unsigned int cpu,
32 const char *namefmt);
33
34 /**
35 * kthread_run - create and wake a thread.
36 * @threadfn: the function to run until signal_pending(current).
37 * @data: data ptr for @threadfn.
38 * @namefmt: printf-style name for the thread.
39 *
40 * Description: Convenient wrapper for kthread_create() followed by
41 * wake_up_process(). Returns the kthread or ERR_PTR(-ENOMEM).
42 */
43 #define kthread_run(threadfn, data, namefmt, ...) \
44 ({ \
45 struct task_struct *__k \
46 = kthread_create(threadfn, data, namefmt, ## __VA_ARGS__); \
47 if (!IS_ERR(__k)) \
48 wake_up_process(__k); \
49 __k; \
50 })
51
52 void free_kthread_struct(struct task_struct *k);
53 void kthread_bind(struct task_struct *k, unsigned int cpu);
54 void kthread_bind_mask(struct task_struct *k, const struct cpumask *mask);
55 int kthread_stop(struct task_struct *k);
56 bool kthread_should_stop(void);
57 bool kthread_should_park(void);
58 bool __kthread_should_park(struct task_struct *k);
59 bool kthread_freezable_should_stop(bool *was_frozen);
60 void *kthread_data(struct task_struct *k);
61 void *kthread_probe_data(struct task_struct *k);
62 int kthread_park(struct task_struct *k);
63 void kthread_unpark(struct task_struct *k);
64 void kthread_parkme(void);
65
66 int kthreadd(void *unused);
67 extern struct task_struct *kthreadd_task;
68 extern int tsk_fork_get_node(struct task_struct *tsk);
69
70 /*
71 * Simple work processor based on kthread.
72 *
73 * This provides easier way to make use of kthreads. A kthread_work
74 * can be queued and flushed using queue/kthread_flush_work()
75 * respectively. Queued kthread_works are processed by a kthread
76 * running kthread_worker_fn().
77 */
78 struct kthread_work;
79 typedef void (*kthread_work_func_t)(struct kthread_work *work);
80 void kthread_delayed_work_timer_fn(struct timer_list *t);
81
82 enum {
83 KTW_FREEZABLE = 1 << 0, /* freeze during suspend */
84 };
85
86 struct kthread_worker {
87 unsigned int flags;
88 raw_spinlock_t lock;
89 struct list_head work_list;
90 struct list_head delayed_work_list;
91 struct task_struct *task;
92 struct kthread_work *current_work;
93 };
94
95 struct kthread_work {
96 struct list_head node;
97 kthread_work_func_t func;
98 struct kthread_worker *worker;
99 /* Number of canceling calls that are running at the moment. */
100 int canceling;
101 };
102
103 struct kthread_delayed_work {
104 struct kthread_work work;
105 struct timer_list timer;
106 };
107
108 #define KTHREAD_WORKER_INIT(worker) { \
109 .lock = __RAW_SPIN_LOCK_UNLOCKED((worker).lock), \
110 .work_list = LIST_HEAD_INIT((worker).work_list), \
111 .delayed_work_list = LIST_HEAD_INIT((worker).delayed_work_list),\
112 }
113
114 #define KTHREAD_WORK_INIT(work, fn) { \
115 .node = LIST_HEAD_INIT((work).node), \
116 .func = (fn), \
117 }
118
119 #define KTHREAD_DELAYED_WORK_INIT(dwork, fn) { \
120 .work = KTHREAD_WORK_INIT((dwork).work, (fn)), \
121 .timer = __TIMER_INITIALIZER(kthread_delayed_work_timer_fn,\
122 TIMER_IRQSAFE), \
123 }
124
125 #define DEFINE_KTHREAD_WORKER(worker) \
126 struct kthread_worker worker = KTHREAD_WORKER_INIT(worker)
127
128 #define DEFINE_KTHREAD_WORK(work, fn) \
129 struct kthread_work work = KTHREAD_WORK_INIT(work, fn)
130
131 #define DEFINE_KTHREAD_DELAYED_WORK(dwork, fn) \
132 struct kthread_delayed_work dwork = \
133 KTHREAD_DELAYED_WORK_INIT(dwork, fn)
134
135 /*
136 * kthread_worker.lock needs its own lockdep class key when defined on
137 * stack with lockdep enabled. Use the following macros in such cases.
138 */
139 #ifdef CONFIG_LOCKDEP
140 # define KTHREAD_WORKER_INIT_ONSTACK(worker) \
141 ({ kthread_init_worker(&worker); worker; })
142 # define DEFINE_KTHREAD_WORKER_ONSTACK(worker) \
143 struct kthread_worker worker = KTHREAD_WORKER_INIT_ONSTACK(worker)
144 #else
145 # define DEFINE_KTHREAD_WORKER_ONSTACK(worker) DEFINE_KTHREAD_WORKER(worker)
146 #endif
147
148 extern void __kthread_init_worker(struct kthread_worker *worker,
149 const char *name, struct lock_class_key *key);
150
151 #define kthread_init_worker(worker) \
152 do { \
153 static struct lock_class_key __key; \
154 __kthread_init_worker((worker), "("#worker")->lock", &__key); \
155 } while (0)
156
157 #define kthread_init_work(work, fn) \
158 do { \
159 memset((work), 0, sizeof(struct kthread_work)); \
160 INIT_LIST_HEAD(&(work)->node); \
161 (work)->func = (fn); \
162 } while (0)
163
164 #define kthread_init_delayed_work(dwork, fn) \
165 do { \
166 kthread_init_work(&(dwork)->work, (fn)); \
167 timer_setup(&(dwork)->timer, \
168 kthread_delayed_work_timer_fn, 0); \
169 } while (0)
170
171 int kthread_worker_fn(void *worker_ptr);
172
173 __printf(2, 3)
174 struct kthread_worker *
175 kthread_create_worker(unsigned int flags, const char namefmt[], ...);
176
177 __printf(3, 4) struct kthread_worker *
178 kthread_create_worker_on_cpu(int cpu, unsigned int flags,
179 const char namefmt[], ...);
180
181 bool kthread_queue_work(struct kthread_worker *worker,
182 struct kthread_work *work);
183
184 bool kthread_queue_delayed_work(struct kthread_worker *worker,
185 struct kthread_delayed_work *dwork,
186 unsigned long delay);
187
188 bool kthread_mod_delayed_work(struct kthread_worker *worker,
189 struct kthread_delayed_work *dwork,
190 unsigned long delay);
191
192 void kthread_flush_work(struct kthread_work *work);
193 void kthread_flush_worker(struct kthread_worker *worker);
194
195 bool kthread_cancel_work_sync(struct kthread_work *work);
196 bool kthread_cancel_delayed_work_sync(struct kthread_delayed_work *work);
197
198 void kthread_destroy_worker(struct kthread_worker *worker);
199
200 struct cgroup_subsys_state;
201
202 #ifdef CONFIG_BLK_CGROUP
203 void kthread_associate_blkcg(struct cgroup_subsys_state *css);
204 struct cgroup_subsys_state *kthread_blkcg(void);
205 #else
kthread_associate_blkcg(struct cgroup_subsys_state * css)206 static inline void kthread_associate_blkcg(struct cgroup_subsys_state *css) { }
kthread_blkcg(void)207 static inline struct cgroup_subsys_state *kthread_blkcg(void)
208 {
209 return NULL;
210 }
211 #endif
212 #endif /* _LINUX_KTHREAD_H */
213