include/linux/kthread.h

   1 #ifndef _LINUX_KTHREAD_H
   2 #define _LINUX_KTHREAD_H
   3 /* Simple interface for creating and stopping kernel threads without mess. */
   4 #include <linux/err.h>
   5 #include <linux/sched.h>
   6
   7 __printf(4, 5)
   8 struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
   9                                            void *data,
  10                                            int node,
  11                                            const char namefmt[], ...);
  12
  13 #define kthread_create(threadfn, data, namefmt, arg...) \
  14         kthread_create_on_node(threadfn, data, -1, namefmt, ##arg)
  15
  16
  17 struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data),
  18                                           void *data,
  19                                           unsigned int cpu,
  20                                           const char *namefmt);
  21
  22 /**
  23  * kthread_run - create and wake a thread.
  24  * @threadfn: the function to run until signal_pending(current).
  25  * @data: data ptr for @threadfn.
  26  * @namefmt: printf-style name for the thread.
  27  *
  28  * Description: Convenient wrapper for kthread_create() followed by
  29  * wake_up_process().  Returns the kthread or ERR_PTR(-ENOMEM).
  30  */
  31 #define kthread_run(threadfn, data, namefmt, ...)                          \
  32 ({                                                                         \
  33         struct task_struct *__k                                            \
  34                 = kthread_create(threadfn, data, namefmt, ## __VA_ARGS__); \
  35         if (!IS_ERR(__k))                                                  \
  36                 wake_up_process(__k);                                      \
  37         __k;                                                               \
  38 })
  39
  40 void kthread_bind(struct task_struct *k, unsigned int cpu);
  41 int kthread_stop(struct task_struct *k);
  42 bool kthread_should_stop(void);
  43 bool kthread_should_park(void);
  44 bool kthread_freezable_should_stop(bool *was_frozen);
  45 void *kthread_data(struct task_struct *k);
  46 int kthread_park(struct task_struct *k);
  47 void kthread_unpark(struct task_struct *k);
  48 void kthread_parkme(void);
  49
  50 int kthreadd(void *unused);
  51 extern struct task_struct *kthreadd_task;
  52 extern int tsk_fork_get_node(struct task_struct *tsk);
  53
  54 /*
  55  * Simple work processor based on kthread.
  56  *
  57  * This provides easier way to make use of kthreads.  A kthread_work
  58  * can be queued and flushed using queue/flush_kthread_work()
  59  * respectively.  Queued kthread_works are processed by a kthread
  60  * running kthread_worker_fn().
  61  */
  62 struct kthread_work;
  63 typedef void (*kthread_work_func_t)(struct kthread_work *work);
  64
  65 struct kthread_worker {
  66         spinlock_t              lock;
  67         struct list_head        work_list;
  68         struct task_struct      *task;
  69         struct kthread_work     *current_work;
  70 };
  71
  72 struct kthread_work {
  73         struct list_head        node;
  74         kthread_work_func_t     func;
  75         wait_queue_head_t       done;
  76         struct kthread_worker   *worker;
  77 };
  78
  79 #define KTHREAD_WORKER_INIT(worker)     {                               \
  80         .lock = __SPIN_LOCK_UNLOCKED((worker).lock),                    \
  81         .work_list = LIST_HEAD_INIT((worker).work_list),                \
  82         }
  83
  84 #define KTHREAD_WORK_INIT(work, fn)     {                               \
  85         .node = LIST_HEAD_INIT((work).node),                            \
  86         .func = (fn),                                                   \
  87         .done = __WAIT_QUEUE_HEAD_INITIALIZER((work).done),             \
  88         }
  89
  90 #define DEFINE_KTHREAD_WORKER(worker)                                   \
  91         struct kthread_worker worker = KTHREAD_WORKER_INIT(worker)
  92
  93 #define DEFINE_KTHREAD_WORK(work, fn)                                   \
  94         struct kthread_work work = KTHREAD_WORK_INIT(work, fn)
  95
  96 /*
  97  * kthread_worker.lock and kthread_work.done need their own lockdep class
  98  * keys if they are defined on stack with lockdep enabled.  Use the
  99  * following macros when defining them on stack.
 100  */
 101 #ifdef CONFIG_LOCKDEP
 102 # define KTHREAD_WORKER_INIT_ONSTACK(worker)                            \
 103         ({ init_kthread_worker(&worker); worker; })
 104 # define DEFINE_KTHREAD_WORKER_ONSTACK(worker)                          \
 105         struct kthread_worker worker = KTHREAD_WORKER_INIT_ONSTACK(worker)
 106 # define KTHREAD_WORK_INIT_ONSTACK(work, fn)                            \
 107         ({ init_kthread_work((&work), fn); work; })
 108 # define DEFINE_KTHREAD_WORK_ONSTACK(work, fn)                          \
 109         struct kthread_work work = KTHREAD_WORK_INIT_ONSTACK(work, fn)
 110 #else
 111 # define DEFINE_KTHREAD_WORKER_ONSTACK(worker) DEFINE_KTHREAD_WORKER(worker)
 112 # define DEFINE_KTHREAD_WORK_ONSTACK(work, fn) DEFINE_KTHREAD_WORK(work, fn)
 113 #endif
 114
 115 extern void __init_kthread_worker(struct kthread_worker *worker,
 116                         const char *name, struct lock_class_key *key);
 117
 118 #define init_kthread_worker(worker)                                     \
 119         do {                                                            \
 120                 static struct lock_class_key __key;                     \
 121                 __init_kthread_worker((worker), "("#worker")->lock", &__key); \
 122         } while (0)
 123
 124 #define init_kthread_work(work, fn)                                     \
 125         do {                                                            \
 126                 memset((work), 0, sizeof(struct kthread_work));         \
 127                 INIT_LIST_HEAD(&(work)->node);                          \
 128                 (work)->func = (fn);                                    \
 129                 init_waitqueue_head(&(work)->done);                     \
 130         } while (0)
 131
 132 int kthread_worker_fn(void *worker_ptr);
 133
 134 bool queue_kthread_work(struct kthread_worker *worker,
 135                         struct kthread_work *work);
 136 void flush_kthread_work(struct kthread_work *work);
 137 void flush_kthread_worker(struct kthread_worker *worker);
 138
 139 #endif /* _LINUX_KTHREAD_H */