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 bool kthread_freezable_should_stop(bool *was_frozen);
  39 void *kthread_data(struct task_struct *k);
  40
  41 int kthreadd(void *unused);
  42 extern struct task_struct *kthreadd_task;
  43 extern int tsk_fork_get_node(struct task_struct *tsk);
  44
  45 /*
  46  * Simple work processor based on kthread.
  47  *
  48  * This provides easier way to make use of kthreads.  A kthread_work
  49  * can be queued and flushed using queue/flush_kthread_work()
  50  * respectively.  Queued kthread_works are processed by a kthread
  51  * running kthread_worker_fn().
  52  */
  53 struct kthread_work;
  54 typedef void (*kthread_work_func_t)(struct kthread_work *work);
  55
  56 struct kthread_worker {
  57         spinlock_t              lock;
  58         struct list_head        work_list;
  59         struct task_struct      *task;
  60         struct kthread_work     *current_work;
  61 };
  62
  63 struct kthread_work {
  64         struct list_head        node;
  65         kthread_work_func_t     func;
  66         wait_queue_head_t       done;
  67         struct kthread_worker   *worker;
  68 };
  69
  70 #define KTHREAD_WORKER_INIT(worker)     {                               \
  71         .lock = __SPIN_LOCK_UNLOCKED((worker).lock),                    \
  72         .work_list = LIST_HEAD_INIT((worker).work_list),                \
  73         }
  74
  75 #define KTHREAD_WORK_INIT(work, fn)     {                               \
  76         .node = LIST_HEAD_INIT((work).node),                            \
  77         .func = (fn),                                                   \
  78         .done = __WAIT_QUEUE_HEAD_INITIALIZER((work).done),             \
  79         }
  80
  81 #define DEFINE_KTHREAD_WORKER(worker)                                   \
  82         struct kthread_worker worker = KTHREAD_WORKER_INIT(worker)
  83
  84 #define DEFINE_KTHREAD_WORK(work, fn)                                   \
  85         struct kthread_work work = KTHREAD_WORK_INIT(work, fn)
  86
  87 /*
  88  * kthread_worker.lock and kthread_work.done need their own lockdep class
  89  * keys if they are defined on stack with lockdep enabled.  Use the
  90  * following macros when defining them on stack.
  91  */
  92 #ifdef CONFIG_LOCKDEP
  93 # define KTHREAD_WORKER_INIT_ONSTACK(worker)                            \
  94         ({ init_kthread_worker(&worker); worker; })
  95 # define DEFINE_KTHREAD_WORKER_ONSTACK(worker)                          \
  96         struct kthread_worker worker = KTHREAD_WORKER_INIT_ONSTACK(worker)
  97 # define KTHREAD_WORK_INIT_ONSTACK(work, fn)                            \
  98         ({ init_kthread_work((&work), fn); work; })
  99 # define DEFINE_KTHREAD_WORK_ONSTACK(work, fn)                          \
 100         struct kthread_work work = KTHREAD_WORK_INIT_ONSTACK(work, fn)
 101 #else
 102 # define DEFINE_KTHREAD_WORKER_ONSTACK(worker) DEFINE_KTHREAD_WORKER(worker)
 103 # define DEFINE_KTHREAD_WORK_ONSTACK(work, fn) DEFINE_KTHREAD_WORK(work, fn)
 104 #endif
 105
 106 extern void __init_kthread_worker(struct kthread_worker *worker,
 107                         const char *name, struct lock_class_key *key);
 108
 109 #define init_kthread_worker(worker)                                     \
 110         do {                                                            \
 111                 static struct lock_class_key __key;                     \
 112                 __init_kthread_worker((worker), "("#worker")->lock", &__key); \
 113         } while (0)
 114
 115 #define init_kthread_work(work, fn)                                     \
 116         do {                                                            \
 117                 memset((work), 0, sizeof(struct kthread_work));         \
 118                 INIT_LIST_HEAD(&(work)->node);                          \
 119                 (work)->func = (fn);                                    \
 120                 init_waitqueue_head(&(work)->done);                     \
 121         } while (0)
 122
 123 int kthread_worker_fn(void *worker_ptr);
 124
 125 bool queue_kthread_work(struct kthread_worker *worker,
 126                         struct kthread_work *work);
 127 void flush_kthread_work(struct kthread_work *work);
 128 void flush_kthread_worker(struct kthread_worker *worker);
 129
 130 #endif /* _LINUX_KTHREAD_H */