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#include <linux/cgroup.h>
8
9__printf(4, 5)
10struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
11 void *data,
12 int node,
13 const char namefmt[], ...);
14
15/**
16 * kthread_create - create a kthread on the current node
17 * @threadfn: the function to run in the thread
18 * @data: data pointer for @threadfn()
19 * @namefmt: printf-style format string for the thread name
20 * @arg...: arguments for @namefmt.
21 *
22 * This macro will create a kthread on the current node, leaving it in
23 * the stopped state. This is just a helper for kthread_create_on_node();
24 * see the documentation there for more details.
25 */
26#define kthread_create(threadfn, data, namefmt, arg...) \
27 kthread_create_on_node(threadfn, data, NUMA_NO_NODE, namefmt, ##arg)
28
29
30struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data),
31 void *data,
32 unsigned int cpu,
33 const char *namefmt);
34
35/**
36 * kthread_run - create and wake a thread.
37 * @threadfn: the function to run until signal_pending(current).
38 * @data: data ptr for @threadfn.
39 * @namefmt: printf-style name for the thread.
40 *
41 * Description: Convenient wrapper for kthread_create() followed by
42 * wake_up_process(). Returns the kthread or ERR_PTR(-ENOMEM).
43 */
44#define kthread_run(threadfn, data, namefmt, ...) \
45({ \
46 struct task_struct *__k \
47 = kthread_create(threadfn, data, namefmt, ## __VA_ARGS__); \
48 if (!IS_ERR(__k)) \
49 wake_up_process(__k); \
50 __k; \
51})
52
53void free_kthread_struct(struct task_struct *k);
54void kthread_bind(struct task_struct *k, unsigned int cpu);
55void kthread_bind_mask(struct task_struct *k, const struct cpumask *mask);
56int kthread_stop(struct task_struct *k);
57bool kthread_should_stop(void);
58bool kthread_should_park(void);
59bool kthread_freezable_should_stop(bool *was_frozen);
60void *kthread_data(struct task_struct *k);
61void *kthread_probe_data(struct task_struct *k);
62int kthread_park(struct task_struct *k);
63void kthread_unpark(struct task_struct *k);
64void kthread_parkme(void);
65
66int kthreadd(void *unused);
67extern struct task_struct *kthreadd_task;
68extern 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 */
78struct kthread_work;
79typedef void (*kthread_work_func_t)(struct kthread_work *work);
80void kthread_delayed_work_timer_fn(struct timer_list *t);
81
82enum {
83 KTW_FREEZABLE = 1 << 0, /* freeze during suspend */
84};
85
86struct kthread_worker {
87 unsigned int flags;
88 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
95struct 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
103struct kthread_delayed_work {
104 struct kthread_work work;
105 struct timer_list timer;
106};
107
108#define KTHREAD_WORKER_INIT(worker) { \
109 .lock = __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
148extern 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 __init_timer(&(dwork)->timer, \
168 kthread_delayed_work_timer_fn, \
169 TIMER_IRQSAFE); \
170 } while (0)
171
172int kthread_worker_fn(void *worker_ptr);
173
174__printf(2, 3)
175struct kthread_worker *
176kthread_create_worker(unsigned int flags, const char namefmt[], ...);
177
178__printf(3, 4) struct kthread_worker *
179kthread_create_worker_on_cpu(int cpu, unsigned int flags,
180 const char namefmt[], ...);
181
182bool kthread_queue_work(struct kthread_worker *worker,
183 struct kthread_work *work);
184
185bool kthread_queue_delayed_work(struct kthread_worker *worker,
186 struct kthread_delayed_work *dwork,
187 unsigned long delay);
188
189bool kthread_mod_delayed_work(struct kthread_worker *worker,
190 struct kthread_delayed_work *dwork,
191 unsigned long delay);
192
193void kthread_flush_work(struct kthread_work *work);
194void kthread_flush_worker(struct kthread_worker *worker);
195
196bool kthread_cancel_work_sync(struct kthread_work *work);
197bool kthread_cancel_delayed_work_sync(struct kthread_delayed_work *work);
198
199void kthread_destroy_worker(struct kthread_worker *worker);
200
201#ifdef CONFIG_BLK_CGROUP
202void kthread_associate_blkcg(struct cgroup_subsys_state *css);
203struct cgroup_subsys_state *kthread_blkcg(void);
204#else
205static inline void kthread_associate_blkcg(struct cgroup_subsys_state *css) { }
206static inline struct cgroup_subsys_state *kthread_blkcg(void)
207{
208 return NULL;
209}
210#endif
211#endif /* _LINUX_KTHREAD_H */
212