LXR linux/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)
   8struct 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
  35void kthread_bind(struct task_struct *k, unsigned int cpu);
  36int kthread_stop(struct task_struct *k);
  37int kthread_should_stop(void);
  38bool kthread_freezable_should_stop(bool *was_frozen);
  39void *kthread_data(struct task_struct *k);
  40
  41int kthreadd(void *unused);
  42extern struct task_struct *kthreadd_task;
  43extern 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 * A kthread_work can't be freed while it is executing.
  54 */
  55struct kthread_work;
  56typedef void (*kthread_work_func_t)(struct kthread_work *work);
  57
  58struct kthread_worker {
  59        spinlock_t              lock;
  60        struct list_head        work_list;
  61        struct task_struct      *task;
  62};
  63
  64struct kthread_work {
  65        struct list_head        node;
  66        kthread_work_func_t     func;
  67        wait_queue_head_t       done;
  68        atomic_t                flushing;
  69        int                     queue_seq;
  70        int                     done_seq;
  71};
  72
  73#define KTHREAD_WORKER_INIT(worker)     {                               \
  74        .lock = __SPIN_LOCK_UNLOCKED((worker).lock),                    \
  75        .work_list = LIST_HEAD_INIT((worker).work_list),                \
  76        }
  77
  78#define KTHREAD_WORK_INIT(work, fn)     {                               \
  79        .node = LIST_HEAD_INIT((work).node),                            \
  80        .func = (fn),                                                   \
  81        .done = __WAIT_QUEUE_HEAD_INITIALIZER((work).done),             \
  82        .flushing = ATOMIC_INIT(0),                                     \
  83        }
  84
  85#define DEFINE_KTHREAD_WORKER(worker)                                   \
  86        struct kthread_worker worker = KTHREAD_WORKER_INIT(worker)
  87
  88#define DEFINE_KTHREAD_WORK(work, fn)                                   \
  89        struct kthread_work work = KTHREAD_WORK_INIT(work, fn)
  90
  91/*
  92 * kthread_worker.lock and kthread_work.done need their own lockdep class
  93 * keys if they are defined on stack with lockdep enabled.  Use the
  94 * following macros when defining them on stack.
  95 */
  96#ifdef CONFIG_LOCKDEP
  97# define KTHREAD_WORKER_INIT_ONSTACK(worker)                            \
  98        ({ init_kthread_worker(&worker); worker; })
  99# define DEFINE_KTHREAD_WORKER_ONSTACK(worker)                          \
 100        struct kthread_worker worker = KTHREAD_WORKER_INIT_ONSTACK(worker)
 101# define KTHREAD_WORK_INIT_ONSTACK(work, fn)                            \
 102        ({ init_kthread_work((&work), fn); work; })
 103# define DEFINE_KTHREAD_WORK_ONSTACK(work, fn)                          \
 104        struct kthread_work work = KTHREAD_WORK_INIT_ONSTACK(work, fn)
 105#else
 106# define DEFINE_KTHREAD_WORKER_ONSTACK(worker) DEFINE_KTHREAD_WORKER(worker)
 107# define DEFINE_KTHREAD_WORK_ONSTACK(work, fn) DEFINE_KTHREAD_WORK(work, fn)
 108#endif
 109
 110extern void __init_kthread_worker(struct kthread_worker *worker,
 111                        const char *name, struct lock_class_key *key);
 112
 113#define init_kthread_worker(worker)                                     \
 114        do {                                                            \
 115                static struct lock_class_key __key;                     \
 116                __init_kthread_worker((worker), "("#worker")->lock", &__key); \
 117        } while (0)
 118
 119#define init_kthread_work(work, fn)                                     \
 120        do {                                                            \
 121                memset((work), 0, sizeof(struct kthread_work));         \
 122                INIT_LIST_HEAD(&(work)->node);                          \
 123                (work)->func = (fn);                                    \
 124                init_waitqueue_head(&(work)->done);                     \
 125        } while (0)
 126
 127int kthread_worker_fn(void *worker_ptr);
 128
 129bool queue_kthread_work(struct kthread_worker *worker,
 130                        struct kthread_work *work);
 131void flush_kthread_work(struct kthread_work *work);
 132void flush_kthread_worker(struct kthread_worker *worker);
 133
 134#endif /* _LINUX_KTHREAD_H */
 135