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 struct task_struct *kthread_create(int (*threadfn)(void *data),
   8                                    void *data,
   9                                    const char namefmt[], ...)
  10         __attribute__((format(printf, 3, 4)));
  11
  12 /**
  13  * kthread_run - create and wake a thread.
  14  * @threadfn: the function to run until signal_pending(current).
  15  * @data: data ptr for @threadfn.
  16  * @namefmt: printf-style name for the thread.
  17  *
  18  * Description: Convenient wrapper for kthread_create() followed by
  19  * wake_up_process().  Returns the kthread or ERR_PTR(-ENOMEM).
  20  */
  21 #define kthread_run(threadfn, data, namefmt, ...)                          \
  22 ({                                                                         \
  23         struct task_struct *__k                                            \
  24                 = kthread_create(threadfn, data, namefmt, ## __VA_ARGS__); \
  25         if (!IS_ERR(__k))                                                  \
  26                 wake_up_process(__k);                                      \
  27         __k;                                                               \
  28 })
  29
  30 void kthread_bind(struct task_struct *k, unsigned int cpu);
  31 int kthread_stop(struct task_struct *k);
  32 int kthread_should_stop(void);
  33 void *kthread_data(struct task_struct *k);
  34
  35 int kthreadd(void *unused);
  36 extern struct task_struct *kthreadd_task;
  37
  38 /*
  39  * Simple work processor based on kthread.
  40  *
  41  * This provides easier way to make use of kthreads.  A kthread_work
  42  * can be queued and flushed using queue/flush_kthread_work()
  43  * respectively.  Queued kthread_works are processed by a kthread
  44  * running kthread_worker_fn().
  45  *
  46  * A kthread_work can't be freed while it is executing.
  47  */
  48 struct kthread_work;
  49 typedef void (*kthread_work_func_t)(struct kthread_work *work);
  50
  51 struct kthread_worker {
  52         spinlock_t              lock;
  53         struct list_head        work_list;
  54         struct task_struct      *task;
  55 };
  56
  57 struct kthread_work {
  58         struct list_head        node;
  59         kthread_work_func_t     func;
  60         wait_queue_head_t       done;
  61         atomic_t                flushing;
  62         int                     queue_seq;
  63         int                     done_seq;
  64 };
  65
  66 #define KTHREAD_WORKER_INIT(worker)     {                               \
  67         .lock = SPIN_LOCK_UNLOCKED,                                     \
  68         .work_list = LIST_HEAD_INIT((worker).work_list),                \
  69         }
  70
  71 #define KTHREAD_WORK_INIT(work, fn)     {                               \
  72         .node = LIST_HEAD_INIT((work).node),                            \
  73         .func = (fn),                                                   \
  74         .done = __WAIT_QUEUE_HEAD_INITIALIZER((work).done),             \
  75         .flushing = ATOMIC_INIT(0),                                     \
  76         }
  77
  78 #define DEFINE_KTHREAD_WORKER(worker)                                   \
  79         struct kthread_worker worker = KTHREAD_WORKER_INIT(worker)
  80
  81 #define DEFINE_KTHREAD_WORK(work, fn)                                   \
  82         struct kthread_work work = KTHREAD_WORK_INIT(work, fn)
  83
  84 /*
  85  * kthread_worker.lock and kthread_work.done need their own lockdep class
  86  * keys if they are defined on stack with lockdep enabled.  Use the
  87  * following macros when defining them on stack.
  88  */
  89 #ifdef CONFIG_LOCKDEP
  90 # define KTHREAD_WORKER_INIT_ONSTACK(worker)                            \
  91         ({ init_kthread_worker(&worker); worker; })
  92 # define DEFINE_KTHREAD_WORKER_ONSTACK(worker)                          \
  93         struct kthread_worker worker = KTHREAD_WORKER_INIT_ONSTACK(worker)
  94 # define KTHREAD_WORK_INIT_ONSTACK(work, fn)                            \
  95         ({ init_kthread_work((&work), fn); work; })
  96 # define DEFINE_KTHREAD_WORK_ONSTACK(work, fn)                          \
  97         struct kthread_work work = KTHREAD_WORK_INIT_ONSTACK(work, fn)
  98 #else
  99 # define DEFINE_KTHREAD_WORKER_ONSTACK(worker) DEFINE_KTHREAD_WORKER(worker)
 100 # define DEFINE_KTHREAD_WORK_ONSTACK(work, fn) DEFINE_KTHREAD_WORK(work, fn)
 101 #endif
 102
 103 extern void __init_kthread_worker(struct kthread_worker *worker,
 104                         const char *name, struct lock_class_key *key);
 105
 106 #define init_kthread_worker(worker)                                     \
 107         do {                                                            \
 108                 static struct lock_class_key __key;                     \
 109                 __init_kthread_worker((worker), "("#worker")->lock", &__key); \
 110         } while (0)
 111
 112 #define init_kthread_work(work, fn)                                     \
 113         do {                                                            \
 114                 memset((work), 0, sizeof(struct kthread_work));         \
 115                 INIT_LIST_HEAD(&(work)->node);                          \
 116                 (work)->func = (fn);                                    \
 117                 init_waitqueue_head(&(work)->done);                     \
 118         } while (0)
 119
 120 int kthread_worker_fn(void *worker_ptr);
 121
 122 bool queue_kthread_work(struct kthread_worker *worker,
 123                         struct kthread_work *work);
 124 void flush_kthread_work(struct kthread_work *work);
 125 void flush_kthread_worker(struct kthread_worker *worker);
 126
 127 #endif /* _LINUX_KTHREAD_H */