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 /**
  18  * kthread_run - create and wake a thread.
  19  * @threadfn: the function to run until signal_pending(current).
  20  * @data: data ptr for @threadfn.
  21  * @namefmt: printf-style name for the thread.
  22  *
  23  * Description: Convenient wrapper for kthread_create() followed by
  24  * wake_up_process().  Returns the kthread or ERR_PTR(-ENOMEM).
  25  */
  26 #define kthread_run(threadfn, data, namefmt, ...)                          \
  27 ({                                                                         \
  28         struct task_struct *__k                                            \
  29                 = kthread_create(threadfn, data, namefmt, ## __VA_ARGS__); \
  30         if (!IS_ERR(__k))                                                  \
  31                 wake_up_process(__k);                                      \
  32         __k;                                                               \
  33 })
  34
  35 void kthread_bind(struct task_struct *k, unsigned int cpu);
  36 int kthread_stop(struct task_struct *k);
  37 int kthread_should_stop(void);
  38 void *kthread_data(struct task_struct *k);
  39
  40 int kthreadd(void *unused);
  41 extern struct task_struct *kthreadd_task;
  42 extern int tsk_fork_get_node(struct task_struct *tsk);
  43
  44 /*
  45  * Simple work processor based on kthread.
  46  *
  47  * This provides easier way to make use of kthreads.  A kthread_work
  48  * can be queued and flushed using queue/flush_kthread_work()
  49  * respectively.  Queued kthread_works are processed by a kthread
  50  * running kthread_worker_fn().
  51  *
  52  * A kthread_work can't be freed while it is executing.
  53  */
  54 struct kthread_work;
  55 typedef void (*kthread_work_func_t)(struct kthread_work *work);
  56
  57 struct kthread_worker {
  58         spinlock_t              lock;
  59         struct list_head        work_list;
  60         struct task_struct      *task;
  61 };
  62
  63 struct kthread_work {
  64         struct list_head        node;
  65         kthread_work_func_t     func;
  66         wait_queue_head_t       done;
  67         atomic_t                flushing;
  68         int                     queue_seq;
  69         int                     done_seq;
  70 };
  71
  72 #define KTHREAD_WORKER_INIT(worker)     {                               \
  73         .lock = __SPIN_LOCK_UNLOCKED((worker).lock),                    \
  74         .work_list = LIST_HEAD_INIT((worker).work_list),                \
  75         }
  76
  77 #define KTHREAD_WORK_INIT(work, fn)     {                               \
  78         .node = LIST_HEAD_INIT((work).node),                            \
  79         .func = (fn),                                                   \
  80         .done = __WAIT_QUEUE_HEAD_INITIALIZER((work).done),             \
  81         .flushing = ATOMIC_INIT(0),                                     \
  82         }
  83
  84 #define DEFINE_KTHREAD_WORKER(worker)                                   \
  85         struct kthread_worker worker = KTHREAD_WORKER_INIT(worker)
  86
  87 #define DEFINE_KTHREAD_WORK(work, fn)                                   \
  88         struct kthread_work work = KTHREAD_WORK_INIT(work, fn)
  89
  90 /*
  91  * kthread_worker.lock and kthread_work.done need their own lockdep class
  92  * keys if they are defined on stack with lockdep enabled.  Use the
  93  * following macros when defining them on stack.
  94  */
  95 #ifdef CONFIG_LOCKDEP
  96 # define KTHREAD_WORKER_INIT_ONSTACK(worker)                            \
  97         ({ init_kthread_worker(&worker); worker; })
  98 # define DEFINE_KTHREAD_WORKER_ONSTACK(worker)                          \
  99         struct kthread_worker worker = KTHREAD_WORKER_INIT_ONSTACK(worker)
 100 # define KTHREAD_WORK_INIT_ONSTACK(work, fn)                            \
 101         ({ init_kthread_work((&work), fn); work; })
 102 # define DEFINE_KTHREAD_WORK_ONSTACK(work, fn)                          \
 103         struct kthread_work work = KTHREAD_WORK_INIT_ONSTACK(work, fn)
 104 #else
 105 # define DEFINE_KTHREAD_WORKER_ONSTACK(worker) DEFINE_KTHREAD_WORKER(worker)
 106 # define DEFINE_KTHREAD_WORK_ONSTACK(work, fn) DEFINE_KTHREAD_WORK(work, fn)
 107 #endif
 108
 109 extern void __init_kthread_worker(struct kthread_worker *worker,
 110                         const char *name, struct lock_class_key *key);
 111
 112 #define init_kthread_worker(worker)                                     \
 113         do {                                                            \
 114                 static struct lock_class_key __key;                     \
 115                 __init_kthread_worker((worker), "("#worker")->lock", &__key); \
 116         } while (0)
 117
 118 #define init_kthread_work(work, fn)                                     \
 119         do {                                                            \
 120                 memset((work), 0, sizeof(struct kthread_work));         \
 121                 INIT_LIST_HEAD(&(work)->node);                          \
 122                 (work)->func = (fn);                                    \
 123                 init_waitqueue_head(&(work)->done);                     \
 124         } while (0)
 125
 126 int kthread_worker_fn(void *worker_ptr);
 127
 128 bool queue_kthread_work(struct kthread_worker *worker,
 129                         struct kthread_work *work);
 130 void flush_kthread_work(struct kthread_work *work);
 131 void flush_kthread_worker(struct kthread_worker *worker);
 132
 133 #endif /* _LINUX_KTHREAD_H */