include/linux/kthread.h

   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 bool 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 *
  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 void kthread_exit(long result) __noreturn;
 100 void kthread_complete_and_exit(struct completion *, long) __noreturn;
 101
 102 int kthreadd(void *unused);
 103 extern struct task_struct *kthreadd_task;
 104 extern int tsk_fork_get_node(struct task_struct *tsk);
 105
 106 /*
 107  * Simple work processor based on kthread.
 108  *
 109  * This provides easier way to make use of kthreads.  A kthread_work
 110  * can be queued and flushed using queue/kthread_flush_work()
 111  * respectively.  Queued kthread_works are processed by a kthread
 112  * running kthread_worker_fn().
 113  */
 114 struct kthread_work;
 115 typedef void (*kthread_work_func_t)(struct kthread_work *work);
 116 void kthread_delayed_work_timer_fn(struct timer_list *t);
 117
 118 enum {
 119         KTW_FREEZABLE           = 1 << 0,       /* freeze during suspend */
 120 };
 121
 122 struct kthread_worker {
 123         unsigned int            flags;
 124         raw_spinlock_t          lock;
 125         struct list_head        work_list;
 126         struct list_head        delayed_work_list;
 127         struct task_struct      *task;
 128         struct kthread_work     *current_work;
 129 };
 130
 131 struct kthread_work {
 132         struct list_head        node;
 133         kthread_work_func_t     func;
 134         struct kthread_worker   *worker;
 135         /* Number of canceling calls that are running at the moment. */
 136         int                     canceling;
 137 };
 138
 139 struct kthread_delayed_work {
 140         struct kthread_work work;
 141         struct timer_list timer;
 142 };
 143
 144 #define KTHREAD_WORK_INIT(work, fn)     {                               \
 145         .node = LIST_HEAD_INIT((work).node),                            \
 146         .func = (fn),                                                   \
 147         }
 148
 149 #define KTHREAD_DELAYED_WORK_INIT(dwork, fn) {                          \
 150         .work = KTHREAD_WORK_INIT((dwork).work, (fn)),                  \
 151         .timer = __TIMER_INITIALIZER(kthread_delayed_work_timer_fn,\
 152                                      TIMER_IRQSAFE),                    \
 153         }
 154
 155 #define DEFINE_KTHREAD_WORK(work, fn)                                   \
 156         struct kthread_work work = KTHREAD_WORK_INIT(work, fn)
 157
 158 #define DEFINE_KTHREAD_DELAYED_WORK(dwork, fn)                          \
 159         struct kthread_delayed_work dwork =                             \
 160                 KTHREAD_DELAYED_WORK_INIT(dwork, fn)
 161
 162 extern void __kthread_init_worker(struct kthread_worker *worker,
 163                         const char *name, struct lock_class_key *key);
 164
 165 #define kthread_init_worker(worker)                                     \
 166         do {                                                            \
 167                 static struct lock_class_key __key;                     \
 168                 __kthread_init_worker((worker), "("#worker")->lock", &__key); \
 169         } while (0)
 170
 171 #define kthread_init_work(work, fn)                                     \
 172         do {                                                            \
 173                 memset((work), 0, sizeof(struct kthread_work));         \
 174                 INIT_LIST_HEAD(&(work)->node);                          \
 175                 (work)->func = (fn);                                    \
 176         } while (0)
 177
 178 #define kthread_init_delayed_work(dwork, fn)                            \
 179         do {                                                            \
 180                 kthread_init_work(&(dwork)->work, (fn));                \
 181                 timer_setup(&(dwork)->timer,                            \
 182                              kthread_delayed_work_timer_fn,             \
 183                              TIMER_IRQSAFE);                            \
 184         } while (0)
 185
 186 int kthread_worker_fn(void *worker_ptr);
 187
 188 __printf(2, 3)
 189 struct kthread_worker *
 190 kthread_create_worker(unsigned int flags, const char namefmt[], ...);
 191
 192 __printf(3, 4) struct kthread_worker *
 193 kthread_create_worker_on_cpu(int cpu, unsigned int flags,
 194                              const char namefmt[], ...);
 195
 196 bool kthread_queue_work(struct kthread_worker *worker,
 197                         struct kthread_work *work);
 198
 199 bool kthread_queue_delayed_work(struct kthread_worker *worker,
 200                                 struct kthread_delayed_work *dwork,
 201                                 unsigned long delay);
 202
 203 bool kthread_mod_delayed_work(struct kthread_worker *worker,
 204                               struct kthread_delayed_work *dwork,
 205                               unsigned long delay);
 206
 207 void kthread_flush_work(struct kthread_work *work);
 208 void kthread_flush_worker(struct kthread_worker *worker);
 209
 210 bool kthread_cancel_work_sync(struct kthread_work *work);
 211 bool kthread_cancel_delayed_work_sync(struct kthread_delayed_work *work);
 212
 213 void kthread_destroy_worker(struct kthread_worker *worker);
 214
 215 void kthread_use_mm(struct mm_struct *mm);
 216 void kthread_unuse_mm(struct mm_struct *mm);
 217
 218 struct cgroup_subsys_state;
 219
 220 #ifdef CONFIG_BLK_CGROUP
 221 void kthread_associate_blkcg(struct cgroup_subsys_state *css);
 222 struct cgroup_subsys_state *kthread_blkcg(void);
 223 #else
 224 static inline void kthread_associate_blkcg(struct cgroup_subsys_state *css) { }
 225 #endif
 226 #endif /* _LINUX_KTHREAD_H */